Vulkan® 1.2.148 - A Specification (with all registered extensions)

4. Devices and Queues

Once Vulkan is initialized, devices and queues are the primary objects used to interact with a Vulkan implementation.

Vulkan separates the concept of physical and logical devices. A physical device usually represents a single complete implementation of Vulkan (excluding instance-level functionality) available to the host, of which there are a finite number. A logical device represents an instance of that implementation with its own state and resources independent of other logical devices.

Physical devices are represented by VkPhysicalDevice handles:

// Provided by VK_VERSION_1_0
VK_DEFINE_HANDLE(VkPhysicalDevice)

4.1. Physical Devices

To retrieve a list of physical device objects representing the physical devices installed in the system, call:

// Provided by VK_VERSION_1_0
VkResult vkEnumeratePhysicalDevices(
    VkInstance                                  instance,
    uint32_t*                                   pPhysicalDeviceCount,
    VkPhysicalDevice*                           pPhysicalDevices);

instance is a handle to a Vulkan instance previously created with vkCreateInstance.
pPhysicalDeviceCount is a pointer to an integer related to the number of physical devices available or queried, as described below.
pPhysicalDevices is either NULL or a pointer to an array of VkPhysicalDevice handles.

If pPhysicalDevices is NULL, then the number of physical devices available is returned in pPhysicalDeviceCount. Otherwise, pPhysicalDeviceCount must point to a variable set by the user to the number of elements in the pPhysicalDevices array, and on return the variable is overwritten with the number of handles actually written to pPhysicalDevices. If pPhysicalDeviceCount is less than the number of physical devices available, at most pPhysicalDeviceCount structures will be written. If pPhysicalDeviceCount is smaller than the number of physical devices available, VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available physical devices were returned.

Valid Usage (Implicit)

instance must be a valid VkInstance handle
pPhysicalDeviceCount must be a valid pointer to a uint32_t value
If the value referenced by pPhysicalDeviceCount is not 0, and pPhysicalDevices is not NULL, pPhysicalDevices must be a valid pointer to an array of pPhysicalDeviceCount VkPhysicalDevice handles

Return Codes

Success

VK_SUCCESS
VK_INCOMPLETE

Failure

VK_ERROR_OUT_OF_HOST_MEMORY
VK_ERROR_OUT_OF_DEVICE_MEMORY
VK_ERROR_INITIALIZATION_FAILED

To query general properties of physical devices once enumerated, call:

// Provided by VK_VERSION_1_0
void vkGetPhysicalDeviceProperties(
    VkPhysicalDevice                            physicalDevice,
    VkPhysicalDeviceProperties*                 pProperties);

physicalDevice is the handle to the physical device whose properties will be queried.
pProperties is a pointer to a VkPhysicalDeviceProperties structure in which properties are returned.

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pProperties must be a valid pointer to a VkPhysicalDeviceProperties structure

The VkPhysicalDeviceProperties structure is defined as:

// Provided by VK_VERSION_1_0
typedef struct VkPhysicalDeviceProperties {
    uint32_t                            apiVersion;
    uint32_t                            driverVersion;
    uint32_t                            vendorID;
    uint32_t                            deviceID;
    VkPhysicalDeviceType                deviceType;
    char                                deviceName[VK_MAX_PHYSICAL_DEVICE_NAME_SIZE];
    uint8_t                             pipelineCacheUUID[VK_UUID_SIZE];
    VkPhysicalDeviceLimits              limits;
    VkPhysicalDeviceSparseProperties    sparseProperties;
} VkPhysicalDeviceProperties;

apiVersion is the version of Vulkan supported by the device, encoded as described in Version Numbers.
driverVersion is the vendor-specified version of the driver.
vendorID is a unique identifier for the vendor (see below) of the physical device.
deviceID is a unique identifier for the physical device among devices available from the vendor.
deviceType is a VkPhysicalDeviceType specifying the type of device.
deviceName is an array of VK_MAX_PHYSICAL_DEVICE_NAME_SIZE char containing a null-terminated UTF-8 string which is the name of the device.
pipelineCacheUUID is an array of VK_UUID_SIZE uint8_t values representing a universally unique identifier for the device.
limits is the VkPhysicalDeviceLimits structure specifying device-specific limits of the physical device. See Limits for details.
sparseProperties is the VkPhysicalDeviceSparseProperties structure specifying various sparse related properties of the physical device. See Sparse Properties for details.

Note

The value of apiVersion may be different than the version returned by vkEnumerateInstanceVersion; either higher or lower. In such cases, the application must not use functionality that exceeds the version of Vulkan associated with a given object. The pApiVersion parameter returned by vkEnumerateInstanceVersion is the version associated with a VkInstance and its children, except for a VkPhysicalDevice and its children. VkPhysicalDeviceProperties::apiVersion is the version associated with a VkPhysicalDevice and its children.

The vendorID and deviceID fields are provided to allow applications to adapt to device characteristics that are not adequately exposed by other Vulkan queries.

Note

These may include performance profiles, hardware errata, or other characteristics.

The vendor identified by vendorID is the entity responsible for the most salient characteristics of the underlying implementation of the VkPhysicalDevice being queried.

Note

For example, in the case of a discrete GPU implementation, this should be the GPU chipset vendor. In the case of a hardware accelerator integrated into a system-on-chip (SoC), this should be the supplier of the silicon IP used to create the accelerator.

If the vendor has a PCI vendor ID, the low 16 bits of vendorID must contain that PCI vendor ID, and the remaining bits must be set to zero. Otherwise, the value returned must be a valid Khronos vendor ID, obtained as described in the Vulkan Documentation and Extensions: Procedures and Conventions document in the section “Registering a Vendor ID with Khronos”. Khronos vendor IDs are allocated starting at 0x10000, to distinguish them from the PCI vendor ID namespace. Khronos vendor IDs are symbolically defined in the VkVendorId type.

The vendor is also responsible for the value returned in deviceID. If the implementation is driven primarily by a PCI device with a PCI device ID, the low 16 bits of deviceID must contain that PCI device ID, and the remaining bits must be set to zero. Otherwise, the choice of what values to return may be dictated by operating system or platform policies - but should uniquely identify both the device version and any major configuration options (for example, core count in the case of multicore devices).

Note

The same device ID should be used for all physical implementations of that device version and configuration. For example, all uses of a specific silicon IP GPU version and configuration should use the same device ID, even if those uses occur in different SoCs.

Khronos vendor IDs which may be returned in VkPhysicalDeviceProperties::vendorID are:

// Provided by VK_VERSION_1_0
typedef enum VkVendorId {
    VK_VENDOR_ID_VIV = 0x10001,
    VK_VENDOR_ID_VSI = 0x10002,
    VK_VENDOR_ID_KAZAN = 0x10003,
    VK_VENDOR_ID_CODEPLAY = 0x10004,
    VK_VENDOR_ID_MESA = 0x10005,
} VkVendorId;

Note

Khronos vendor IDs may be allocated by vendors at any time. Only the latest canonical versions of this Specification, of the corresponding vk.xml API Registry, and of the corresponding vulkan_core.h header file must contain all reserved Khronos vendor IDs.

Only Khronos vendor IDs are given symbolic names at present. PCI vendor IDs returned by the implementation can be looked up in the PCI-SIG database.

The physical device types which may be returned in VkPhysicalDeviceProperties::deviceType are:

// Provided by VK_VERSION_1_0
typedef enum VkPhysicalDeviceType {
    VK_PHYSICAL_DEVICE_TYPE_OTHER = 0,
    VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU = 1,
    VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU = 2,
    VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU = 3,
    VK_PHYSICAL_DEVICE_TYPE_CPU = 4,
} VkPhysicalDeviceType;

VK_PHYSICAL_DEVICE_TYPE_OTHER - the device does not match any other available types.
VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU - the device is typically one embedded in or tightly coupled with the host.
VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU - the device is typically a separate processor connected to the host via an interlink.
VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU - the device is typically a virtual node in a virtualization environment.
VK_PHYSICAL_DEVICE_TYPE_CPU - the device is typically running on the same processors as the host.

The physical device type is advertised for informational purposes only, and does not directly affect the operation of the system. However, the device type may correlate with other advertised properties or capabilities of the system, such as how many memory heaps there are.

To query general properties of physical devices once enumerated, call:

// Provided by VK_VERSION_1_1
void vkGetPhysicalDeviceProperties2(
    VkPhysicalDevice                            physicalDevice,
    VkPhysicalDeviceProperties2*                pProperties);

or the equivalent command

// Provided by VK_KHR_get_physical_device_properties2
void vkGetPhysicalDeviceProperties2KHR(
    VkPhysicalDevice                            physicalDevice,
    VkPhysicalDeviceProperties2*                pProperties);

physicalDevice is the handle to the physical device whose properties will be queried.
pProperties is a pointer to a VkPhysicalDeviceProperties2 structure in which properties are returned.

Each structure in pProperties and its pNext chain contain members corresponding to properties or implementation-dependent limits. vkGetPhysicalDeviceProperties2 writes each member to a value indicating the value of that property or limit.

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pProperties must be a valid pointer to a VkPhysicalDeviceProperties2 structure

The VkPhysicalDeviceProperties2 structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkPhysicalDeviceProperties2 {
    VkStructureType               sType;
    void*                         pNext;
    VkPhysicalDeviceProperties    properties;
} VkPhysicalDeviceProperties2;

or the equivalent

// Provided by VK_KHR_get_physical_device_properties2
typedef VkPhysicalDeviceProperties2 VkPhysicalDeviceProperties2KHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
properties is a VkPhysicalDeviceProperties structure describing properties of the physical device. This structure is written with the same values as if it were written by vkGetPhysicalDeviceProperties.

The pNext chain of this structure is used to extend the structure with properties defined by extensions.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2
Each pNext member of any structure (including this one) in the pNext chain must be either NULL or a pointer to a valid instance of VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT, VkPhysicalDeviceConservativeRasterizationPropertiesEXT, VkPhysicalDeviceCooperativeMatrixPropertiesNV, VkPhysicalDeviceCustomBorderColorPropertiesEXT, VkPhysicalDeviceDepthStencilResolveProperties, VkPhysicalDeviceDescriptorIndexingProperties, VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV, VkPhysicalDeviceDiscardRectanglePropertiesEXT, VkPhysicalDeviceDriverProperties, VkPhysicalDeviceExternalMemoryHostPropertiesEXT, VkPhysicalDeviceFloatControlsProperties, VkPhysicalDeviceFragmentDensityMap2PropertiesEXT, VkPhysicalDeviceFragmentDensityMapPropertiesEXT, VkPhysicalDeviceIDProperties, VkPhysicalDeviceInlineUniformBlockPropertiesEXT, VkPhysicalDeviceLineRasterizationPropertiesEXT, VkPhysicalDeviceMaintenance3Properties, VkPhysicalDeviceMeshShaderPropertiesNV, VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX, VkPhysicalDeviceMultiviewProperties, VkPhysicalDevicePCIBusInfoPropertiesEXT, VkPhysicalDevicePerformanceQueryPropertiesKHR, VkPhysicalDevicePointClippingProperties, VkPhysicalDeviceProtectedMemoryProperties, VkPhysicalDevicePushDescriptorPropertiesKHR, VkPhysicalDeviceRayTracingPropertiesKHR, VkPhysicalDeviceRayTracingPropertiesNV, VkPhysicalDeviceRobustness2PropertiesEXT, VkPhysicalDeviceSampleLocationsPropertiesEXT, VkPhysicalDeviceSamplerFilterMinmaxProperties, VkPhysicalDeviceShaderCoreProperties2AMD, VkPhysicalDeviceShaderCorePropertiesAMD, VkPhysicalDeviceShaderSMBuiltinsPropertiesNV, VkPhysicalDeviceShadingRateImagePropertiesNV, VkPhysicalDeviceSubgroupProperties, VkPhysicalDeviceSubgroupSizeControlPropertiesEXT, VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT, VkPhysicalDeviceTimelineSemaphoreProperties, VkPhysicalDeviceTransformFeedbackPropertiesEXT, VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT, VkPhysicalDeviceVulkan11Properties, or VkPhysicalDeviceVulkan12Properties
The sType value of each struct in the pNext chain must be unique

To query the properties of the driver corresponding to Vulkan 1.1 functionality, add VkPhysicalDeviceVulkan11Properties to the pNext chain of the VkPhysicalDeviceProperties2 structure.

The VkPhysicalDeviceVulkan11Properties structure is defined as:

// Provided by VK_VERSION_1_2
typedef struct VkPhysicalDeviceVulkan11Properties {
    VkStructureType            sType;
    void*                      pNext;
    uint8_t                    deviceUUID[VK_UUID_SIZE];
    uint8_t                    driverUUID[VK_UUID_SIZE];
    uint8_t                    deviceLUID[VK_LUID_SIZE];
    uint32_t                   deviceNodeMask;
    VkBool32                   deviceLUIDValid;
    uint32_t                   subgroupSize;
    VkShaderStageFlags         subgroupSupportedStages;
    VkSubgroupFeatureFlags     subgroupSupportedOperations;
    VkBool32                   subgroupQuadOperationsInAllStages;
    VkPointClippingBehavior    pointClippingBehavior;
    uint32_t                   maxMultiviewViewCount;
    uint32_t                   maxMultiviewInstanceIndex;
    VkBool32                   protectedNoFault;
    uint32_t                   maxPerSetDescriptors;
    VkDeviceSize               maxMemoryAllocationSize;
} VkPhysicalDeviceVulkan11Properties;

deviceUUID is an array of VK_UUID_SIZE uint8_t values representing a universally unique identifier for the device.
driverUUID is an array of VK_UUID_SIZE uint8_t values representing a universally unique identifier for the driver build in use by the device.
deviceLUID is an array of VK_LUID_SIZE uint8_t values representing a locally unique identifier for the device.
deviceNodeMask is a uint32_t bitfield identifying the node within a linked device adapter corresponding to the device.
deviceLUIDValid is a boolean value that will be VK_TRUE if deviceLUID contains a valid LUID and deviceNodeMask contains a valid node mask, and VK_FALSE if they do not.
subgroupSize is the default number of invocations in each subgroup. subgroupSize is at least 1 if any of the physical device’s queues support VK_QUEUE_GRAPHICS_BIT or VK_QUEUE_COMPUTE_BIT. subgroupSize is a power-of-two.
subgroupSupportedStages is a bitfield of VkShaderStageFlagBits describing the shader stages that subgroup operations are supported in. subgroupSupportedStages will have the VK_SHADER_STAGE_COMPUTE_BIT bit set if any of the physical device’s queues support VK_QUEUE_COMPUTE_BIT.
subgroupSupportedOperations is a bitmask of VkSubgroupFeatureFlagBits specifying the sets of subgroup operations supported on this device. subgroupSupportedOperations will have the VK_SUBGROUP_FEATURE_BASIC_BIT bit set if any of the physical device’s queues support VK_QUEUE_GRAPHICS_BIT or VK_QUEUE_COMPUTE_BIT.
subgroupQuadOperationsInAllStages is a boolean specifying whether quad subgroup operations are available in all stages, or are restricted to fragment and compute stages.
pointClippingBehavior is a VkPointClippingBehavior value specifying the point clipping behavior supported by the implementation.
maxMultiviewViewCount is one greater than the maximum view index that can be used in a subpass.
maxMultiviewInstanceIndex is the maximum valid value of instance index allowed to be generated by a drawing command recorded within a subpass of a multiview render pass instance.
protectedNoFault specifies the behavior of the implementation when protected memory access rules are broken. If protectedNoFault is VK_TRUE, breaking those rules will not result in process termination or device loss.
maxPerSetDescriptors is a maximum number of descriptors (summed over all descriptor types) in a single descriptor set that is guaranteed to satisfy any implementation-dependent constraints on the size of a descriptor set itself. Applications can query whether a descriptor set that goes beyond this limit is supported using vkGetDescriptorSetLayoutSupport.
maxMemoryAllocationSize is the maximum size of a memory allocation that can be created, even if there is more space available in the heap.

The members of VkPhysicalDeviceVulkan11Properties must have the same values as the corresponding members of VkPhysicalDeviceIDProperties, VkPhysicalDeviceSubgroupProperties, VkPhysicalDevicePointClippingProperties, VkPhysicalDeviceMultiviewProperties, VkPhysicalDeviceProtectedMemoryProperties, and VkPhysicalDeviceMaintenance3Properties.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_1_PROPERTIES

To query the properties of the driver corresponding to Vulkan 1.2 functionality, add VkPhysicalDeviceVulkan12Properties to the pNext chain of the VkPhysicalDeviceProperties2 structure.

The VkPhysicalDeviceVulkan12Properties structure is defined as:

// Provided by VK_VERSION_1_2
typedef struct VkPhysicalDeviceVulkan12Properties {
    VkStructureType                      sType;
    void*                                pNext;
    VkDriverId                           driverID;
    char                                 driverName[VK_MAX_DRIVER_NAME_SIZE];
    char                                 driverInfo[VK_MAX_DRIVER_INFO_SIZE];
    VkConformanceVersion                 conformanceVersion;
    VkShaderFloatControlsIndependence    denormBehaviorIndependence;
    VkShaderFloatControlsIndependence    roundingModeIndependence;
    VkBool32                             shaderSignedZeroInfNanPreserveFloat16;
    VkBool32                             shaderSignedZeroInfNanPreserveFloat32;
    VkBool32                             shaderSignedZeroInfNanPreserveFloat64;
    VkBool32                             shaderDenormPreserveFloat16;
    VkBool32                             shaderDenormPreserveFloat32;
    VkBool32                             shaderDenormPreserveFloat64;
    VkBool32                             shaderDenormFlushToZeroFloat16;
    VkBool32                             shaderDenormFlushToZeroFloat32;
    VkBool32                             shaderDenormFlushToZeroFloat64;
    VkBool32                             shaderRoundingModeRTEFloat16;
    VkBool32                             shaderRoundingModeRTEFloat32;
    VkBool32                             shaderRoundingModeRTEFloat64;
    VkBool32                             shaderRoundingModeRTZFloat16;
    VkBool32                             shaderRoundingModeRTZFloat32;
    VkBool32                             shaderRoundingModeRTZFloat64;
    uint32_t                             maxUpdateAfterBindDescriptorsInAllPools;
    VkBool32                             shaderUniformBufferArrayNonUniformIndexingNative;
    VkBool32                             shaderSampledImageArrayNonUniformIndexingNative;
    VkBool32                             shaderStorageBufferArrayNonUniformIndexingNative;
    VkBool32                             shaderStorageImageArrayNonUniformIndexingNative;
    VkBool32                             shaderInputAttachmentArrayNonUniformIndexingNative;
    VkBool32                             robustBufferAccessUpdateAfterBind;
    VkBool32                             quadDivergentImplicitLod;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindSamplers;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindUniformBuffers;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindStorageBuffers;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindSampledImages;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindStorageImages;
    uint32_t                             maxPerStageDescriptorUpdateAfterBindInputAttachments;
    uint32_t                             maxPerStageUpdateAfterBindResources;
    uint32_t                             maxDescriptorSetUpdateAfterBindSamplers;
    uint32_t                             maxDescriptorSetUpdateAfterBindUniformBuffers;
    uint32_t                             maxDescriptorSetUpdateAfterBindUniformBuffersDynamic;
    uint32_t                             maxDescriptorSetUpdateAfterBindStorageBuffers;
    uint32_t                             maxDescriptorSetUpdateAfterBindStorageBuffersDynamic;
    uint32_t                             maxDescriptorSetUpdateAfterBindSampledImages;
    uint32_t                             maxDescriptorSetUpdateAfterBindStorageImages;
    uint32_t                             maxDescriptorSetUpdateAfterBindInputAttachments;
    VkResolveModeFlags                   supportedDepthResolveModes;
    VkResolveModeFlags                   supportedStencilResolveModes;
    VkBool32                             independentResolveNone;
    VkBool32                             independentResolve;
    VkBool32                             filterMinmaxSingleComponentFormats;
    VkBool32                             filterMinmaxImageComponentMapping;
    uint64_t                             maxTimelineSemaphoreValueDifference;
    VkSampleCountFlags                   framebufferIntegerColorSampleCounts;
} VkPhysicalDeviceVulkan12Properties;

driverID is a unique identifier for the driver of the physical device.
driverName is an array of VK_MAX_DRIVER_NAME_SIZE char containing a null-terminated UTF-8 string which is the name of the driver.
driverInfo is an array of VK_MAX_DRIVER_INFO_SIZE char containing a null-terminated UTF-8 string with additional information about the driver.
conformanceVersion is the version of the Vulkan conformance test this driver is conformant against (see VkConformanceVersion).
denormBehaviorIndependence is a VkShaderFloatControlsIndependence value indicating whether, and how, denorm behavior can be set independently for different bit widths.
roundingModeIndependence is a VkShaderFloatControlsIndependence value indicating whether, and how, rounding modes can be set independently for different bit widths.
shaderSignedZeroInfNanPreserveFloat16 is a boolean value indicating whether sign of a zero, Nans and $\pm \infty$ can be preserved in 16-bit floating-point computations. It also indicates whether the SignedZeroInfNanPreserve execution mode can be used for 16-bit floating-point types.
shaderSignedZeroInfNanPreserveFloat32 is a boolean value indicating whether sign of a zero, Nans and $\pm \infty$ can be preserved in 32-bit floating-point computations. It also indicates whether the SignedZeroInfNanPreserve execution mode can be used for 32-bit floating-point types.
shaderSignedZeroInfNanPreserveFloat64 is a boolean value indicating whether sign of a zero, Nans and $\pm \infty$ can be preserved in 64-bit floating-point computations. It also indicates whether the SignedZeroInfNanPreserve execution mode can be used for 64-bit floating-point types.
shaderDenormPreserveFloat16 is a boolean value indicating whether denormals can be preserved in 16-bit floating-point computations. It also indicates whether the DenormPreserve execution mode can be used for 16-bit floating-point types.
shaderDenormPreserveFloat32 is a boolean value indicating whether denormals can be preserved in 32-bit floating-point computations. It also indicates whether the DenormPreserve execution mode can be used for 32-bit floating-point types.
shaderDenormPreserveFloat64 is a boolean value indicating whether denormals can be preserved in 64-bit floating-point computations. It also indicates whether the DenormPreserve execution mode can be used for 64-bit floating-point types.
shaderDenormFlushToZeroFloat16 is a boolean value indicating whether denormals can be flushed to zero in 16-bit floating-point computations. It also indicates whether the DenormFlushToZero execution mode can be used for 16-bit floating-point types.
shaderDenormFlushToZeroFloat32 is a boolean value indicating whether denormals can be flushed to zero in 32-bit floating-point computations. It also indicates whether the DenormFlushToZero execution mode can be used for 32-bit floating-point types.
shaderDenormFlushToZeroFloat64 is a boolean value indicating whether denormals can be flushed to zero in 64-bit floating-point computations. It also indicates whether the DenormFlushToZero execution mode can be used for 64-bit floating-point types.
shaderRoundingModeRTEFloat16 is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTE execution mode can be used for 16-bit floating-point types.
shaderRoundingModeRTEFloat32 is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTE execution mode can be used for 32-bit floating-point types.
shaderRoundingModeRTEFloat64 is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTE execution mode can be used for 64-bit floating-point types.
shaderRoundingModeRTZFloat16 is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTZ execution mode can be used for 16-bit floating-point types.
shaderRoundingModeRTZFloat32 is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTZ execution mode can be used for 32-bit floating-point types.
shaderRoundingModeRTZFloat64 is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the RoundingModeRTZ execution mode can be used for 64-bit floating-point types.
maxUpdateAfterBindDescriptorsInAllPools is the maximum number of descriptors (summed over all descriptor types) that can be created across all pools that are created with the VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT bit set. Pool creation may fail when this limit is exceeded, or when the space this limit represents is unable to satisfy a pool creation due to fragmentation.
shaderUniformBufferArrayNonUniformIndexingNative is a boolean value indicating whether uniform buffer descriptors natively support nonuniform indexing. If this is VK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of uniform buffers may execute multiple times in order to access all the descriptors.
shaderSampledImageArrayNonUniformIndexingNative is a boolean value indicating whether sampler and image descriptors natively support nonuniform indexing. If this is VK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of samplers or images may execute multiple times in order to access all the descriptors.
shaderStorageBufferArrayNonUniformIndexingNative is a boolean value indicating whether storage buffer descriptors natively support nonuniform indexing. If this is VK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage buffers may execute multiple times in order to access all the descriptors.
shaderStorageImageArrayNonUniformIndexingNative is a boolean value indicating whether storage image descriptors natively support nonuniform indexing. If this is VK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage images may execute multiple times in order to access all the descriptors.
shaderInputAttachmentArrayNonUniformIndexingNative is a boolean value indicating whether input attachment descriptors natively support nonuniform indexing. If this is VK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of input attachments may execute multiple times in order to access all the descriptors.
robustBufferAccessUpdateAfterBind is a boolean value indicating whether robustBufferAccess can be enabled in a device simultaneously with descriptorBindingUniformBufferUpdateAfterBind, descriptorBindingStorageBufferUpdateAfterBind, descriptorBindingUniformTexelBufferUpdateAfterBind, and/or descriptorBindingStorageTexelBufferUpdateAfterBind. If this is VK_FALSE, then either robustBufferAccess must be disabled or all of these update-after-bind features must be disabled.
quadDivergentImplicitLod is a boolean value indicating whether implicit level of detail calculations for image operations have well-defined results when the image and/or sampler objects used for the instruction are not uniform within a quad. See Derivative Image Operations.
maxPerStageDescriptorUpdateAfterBindSamplers is similar to maxPerStageDescriptorSamplers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageDescriptorUpdateAfterBindUniformBuffers is similar to maxPerStageDescriptorUniformBuffers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageDescriptorUpdateAfterBindStorageBuffers is similar to maxPerStageDescriptorStorageBuffers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageDescriptorUpdateAfterBindSampledImages is similar to maxPerStageDescriptorSampledImages but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageDescriptorUpdateAfterBindStorageImages is similar to maxPerStageDescriptorStorageImages but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageDescriptorUpdateAfterBindInputAttachments is similar to maxPerStageDescriptorInputAttachments but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxPerStageUpdateAfterBindResources is similar to maxPerStageResources but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindSamplers is similar to maxDescriptorSetSamplers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindUniformBuffers is similar to maxDescriptorSetUniformBuffers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindUniformBuffersDynamic is similar to maxDescriptorSetUniformBuffersDynamic but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindStorageBuffers is similar to maxDescriptorSetStorageBuffers but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindStorageBuffersDynamic is similar to maxDescriptorSetStorageBuffersDynamic but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindSampledImages is similar to maxDescriptorSetSampledImages but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindStorageImages is similar to maxDescriptorSetStorageImages but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
maxDescriptorSetUpdateAfterBindInputAttachments is similar to maxDescriptorSetInputAttachments but counts descriptors from descriptor sets created with or without the VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT bit set.
supportedDepthResolveModes is a bitmask of VkResolveModeFlagBits indicating the set of supported depth resolve modes. VK_RESOLVE_MODE_SAMPLE_ZERO_BIT must be included in the set but implementations may support additional modes.
supportedStencilResolveModes is a bitmask of VkResolveModeFlagBits indicating the set of supported stencil resolve modes. VK_RESOLVE_MODE_SAMPLE_ZERO_BIT must be included in the set but implementations may support additional modes. VK_RESOLVE_MODE_AVERAGE_BIT must not be included in the set.
independentResolveNone is VK_TRUE if the implementation supports setting the depth and stencil resolve modes to different values when one of those modes is VK_RESOLVE_MODE_NONE. Otherwise the implementation only supports setting both modes to the same value.
independentResolve is VK_TRUE if the implementation supports all combinations of the supported depth and stencil resolve modes, including setting either depth or stencil resolve mode to VK_RESOLVE_MODE_NONE. An implementation that supports independentResolve must also support independentResolveNone.
filterMinmaxSingleComponentFormats is a boolean value indicating whether a minimum set of required formats support min/max filtering.
filterMinmaxImageComponentMapping is a boolean value indicating whether the implementation supports non-identity component mapping of the image when doing min/max filtering.
maxTimelineSemaphoreValueDifference indicates the maximum difference allowed by the implementation between the current value of a timeline semaphore and any pending signal or wait operations.
framebufferIntegerColorSampleCounts is a bitmask of VkSampleCountFlagBits indicating the color sample counts that are supported for all framebuffer color attachments with integer formats.

The members of VkPhysicalDeviceVulkan12Properties must have the same values as the corresponding members of VkPhysicalDeviceDriverProperties, VkPhysicalDeviceFloatControlsProperties, VkPhysicalDeviceDescriptorIndexingProperties, VkPhysicalDeviceDepthStencilResolveProperties, VkPhysicalDeviceSamplerFilterMinmaxProperties, and VkPhysicalDeviceTimelineSemaphoreProperties.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_PROPERTIES

To query the UUID and LUID of a device, add a VkPhysicalDeviceIDProperties structure to the pNext chain of the VkPhysicalDeviceProperties2 structure. The VkPhysicalDeviceIDProperties structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkPhysicalDeviceIDProperties {
    VkStructureType    sType;
    void*              pNext;
    uint8_t            deviceUUID[VK_UUID_SIZE];
    uint8_t            driverUUID[VK_UUID_SIZE];
    uint8_t            deviceLUID[VK_LUID_SIZE];
    uint32_t           deviceNodeMask;
    VkBool32           deviceLUIDValid;
} VkPhysicalDeviceIDProperties;

or the equivalent

// Provided by VK_KHR_external_memory_capabilities, VK_KHR_external_semaphore_capabilities, VK_KHR_external_fence_capabilities
typedef VkPhysicalDeviceIDProperties VkPhysicalDeviceIDPropertiesKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.

deviceUUID is an array of VK_UUID_SIZE uint8_t values representing a universally unique identifier for the device.
driverUUID is an array of VK_UUID_SIZE uint8_t values representing a universally unique identifier for the driver build in use by the device.
deviceLUID is an array of VK_LUID_SIZE uint8_t values representing a locally unique identifier for the device.
deviceNodeMask is a uint32_t bitfield identifying the node within a linked device adapter corresponding to the device.
deviceLUIDValid is a boolean value that will be VK_TRUE if deviceLUID contains a valid LUID and deviceNodeMask contains a valid node mask, and VK_FALSE if they do not.

deviceUUID must be immutable for a given device across instances, processes, driver APIs, driver versions, and system reboots.

Applications can compare the driverUUID value across instance and process boundaries, and can make similar queries in external APIs to determine whether they are capable of sharing memory objects and resources using them with the device.

deviceUUID and/or driverUUID must be used to determine whether a particular external object can be shared between driver components, where such a restriction exists as defined in the compatibility table for the particular object type:

If deviceLUIDValid is VK_FALSE, the values of deviceLUID and deviceNodeMask are undefined. If deviceLUIDValid is VK_TRUE and Vulkan is running on the Windows operating system, the contents of deviceLUID can be cast to an LUID object and must be equal to the locally unique identifier of a IDXGIAdapter1 object that corresponds to physicalDevice. If deviceLUIDValid is VK_TRUE, deviceNodeMask must contain exactly one bit. If Vulkan is running on an operating system that supports the Direct3D 12 API and physicalDevice corresponds to an individual device in a linked device adapter, deviceNodeMask identifies the Direct3D 12 node corresponding to physicalDevice. Otherwise, deviceNodeMask must be 1.

Note

Although they have identical descriptions, VkPhysicalDeviceIDProperties::deviceUUID may differ from VkPhysicalDeviceProperties2::pipelineCacheUUID. The former is intended to identify and correlate devices across API and driver boundaries, while the latter is used to identify a compatible device and driver combination to use when serializing and de-serializing pipeline state.

Implementations should return deviceUUID values which are likely to be unique even in the presence of multiple Vulkan implementations (such as a GPU driver and a software renderer; two drivers for different GPUs; or the same Vulkan driver running on two logically different devices).

Khronos' conformance testing can not guarantee that deviceUUID values are actually unique, so implementers should make their own best efforts to ensure this. In particular, hard-coded deviceUUID values, especially all-0 bits, should never be used.

A combination of values unique to the vendor, the driver, and the hardware environment can be used to provide a deviceUUID which is unique to a high degree of certainty. Some possible inputs to such a computation are:

Information reported by vkGetPhysicalDeviceProperties
PCI device ID (if defined)
PCI bus ID, or similar system configuration information.
Driver binary checksums.

Note

While VkPhysicalDeviceIDProperties::deviceUUID is specified to remain consistent across driver versions and system reboots, it is not intended to be usable as a serializable persistent identifier for a device. It may change when a device is physically added to, removed from, or moved to a different connector in a system while that system is powered down. Further, there is no reasonable way to verify with conformance testing that a given device retains the same UUID in a given system across all driver versions supported in that system. While implementations should make every effort to report consistent device UUIDs across driver versions, applications should avoid relying on the persistence of this value for uses other than identifying compatible devices for external object sharing purposes.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES

To query the properties of the driver corresponding to a physical device, add a VkPhysicalDeviceDriverProperties structure to the pNext chain of the VkPhysicalDeviceProperties2 structure. The VkPhysicalDeviceDriverProperties structure is defined as:

// Provided by VK_VERSION_1_2
typedef struct VkPhysicalDeviceDriverProperties {
    VkStructureType         sType;
    void*                   pNext;
    VkDriverId              driverID;
    char                    driverName[VK_MAX_DRIVER_NAME_SIZE];
    char                    driverInfo[VK_MAX_DRIVER_INFO_SIZE];
    VkConformanceVersion    conformanceVersion;
} VkPhysicalDeviceDriverProperties;

or the equivalent

// Provided by VK_KHR_driver_properties
typedef VkPhysicalDeviceDriverProperties VkPhysicalDeviceDriverPropertiesKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.

driverID is a unique identifier for the driver of the physical device.
driverName is an array of VK_MAX_DRIVER_NAME_SIZE char containing a null-terminated UTF-8 string which is the name of the driver.
driverInfo is an array of VK_MAX_DRIVER_INFO_SIZE char containing a null-terminated UTF-8 string with additional information about the driver.
conformanceVersion is the version of the Vulkan conformance test this driver is conformant against (see VkConformanceVersion).

driverID must be immutable for a given driver across instances, processes, driver versions, and system reboots.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES

Khronos driver IDs which may be returned in VkPhysicalDeviceDriverProperties::driverID are:

// Provided by VK_VERSION_1_2
typedef enum VkDriverId {
    VK_DRIVER_ID_AMD_PROPRIETARY = 1,
    VK_DRIVER_ID_AMD_OPEN_SOURCE = 2,
    VK_DRIVER_ID_MESA_RADV = 3,
    VK_DRIVER_ID_NVIDIA_PROPRIETARY = 4,
    VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS = 5,
    VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA = 6,
    VK_DRIVER_ID_IMAGINATION_PROPRIETARY = 7,
    VK_DRIVER_ID_QUALCOMM_PROPRIETARY = 8,
    VK_DRIVER_ID_ARM_PROPRIETARY = 9,
    VK_DRIVER_ID_GOOGLE_SWIFTSHADER = 10,
    VK_DRIVER_ID_GGP_PROPRIETARY = 11,
    VK_DRIVER_ID_BROADCOM_PROPRIETARY = 12,
    VK_DRIVER_ID_MESA_LLVMPIPE = 13,
    VK_DRIVER_ID_MOLTENVK = 14,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_AMD_PROPRIETARY_KHR = VK_DRIVER_ID_AMD_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_AMD_OPEN_SOURCE_KHR = VK_DRIVER_ID_AMD_OPEN_SOURCE,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_MESA_RADV_KHR = VK_DRIVER_ID_MESA_RADV,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_NVIDIA_PROPRIETARY_KHR = VK_DRIVER_ID_NVIDIA_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS_KHR = VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA_KHR = VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_IMAGINATION_PROPRIETARY_KHR = VK_DRIVER_ID_IMAGINATION_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_QUALCOMM_PROPRIETARY_KHR = VK_DRIVER_ID_QUALCOMM_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_ARM_PROPRIETARY_KHR = VK_DRIVER_ID_ARM_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_GOOGLE_SWIFTSHADER_KHR = VK_DRIVER_ID_GOOGLE_SWIFTSHADER,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_GGP_PROPRIETARY_KHR = VK_DRIVER_ID_GGP_PROPRIETARY,
  // Provided by VK_KHR_driver_properties
    VK_DRIVER_ID_BROADCOM_PROPRIETARY_KHR = VK_DRIVER_ID_BROADCOM_PROPRIETARY,
} VkDriverId;

or the equivalent

// Provided by VK_KHR_driver_properties
typedef VkDriverId VkDriverIdKHR;

Note

Khronos driver IDs may be allocated by vendors at any time. There may be multiple driver IDs for the same vendor, representing different drivers (for e.g. different platforms, proprietary or open source, etc.). Only the latest canonical versions of this Specification, of the corresponding vk.xml API Registry, and of the corresponding vulkan_core.h header file must contain all reserved Khronos driver IDs.

Only driver IDs registered with Khronos are given symbolic names. There may be unregistered driver IDs returned.

The conformance test suite version an implementation is compliant with is described with the VkConformanceVersion structure:

// Provided by VK_VERSION_1_2
typedef struct VkConformanceVersion {
    uint8_t    major;
    uint8_t    minor;
    uint8_t    subminor;
    uint8_t    patch;
} VkConformanceVersion;

or the equivalent

// Provided by VK_KHR_driver_properties
typedef VkConformanceVersion VkConformanceVersionKHR;

major is the major version number of the conformance test suite.
minor is the minor version number of the conformance test suite.
subminor is the subminor version number of the conformance test suite.
patch is the patch version number of the conformance test suite.

To query the PCI bus information of a physical device, add a VkPhysicalDevicePCIBusInfoPropertiesEXT structure to the pNext chain of the VkPhysicalDeviceProperties2 structure. The VkPhysicalDevicePCIBusInfoPropertiesEXT structure is defined as:

// Provided by VK_EXT_pci_bus_info
typedef struct VkPhysicalDevicePCIBusInfoPropertiesEXT {
    VkStructureType    sType;
    void*              pNext;
    uint32_t           pciDomain;
    uint32_t           pciBus;
    uint32_t           pciDevice;
    uint32_t           pciFunction;
} VkPhysicalDevicePCIBusInfoPropertiesEXT;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
pciDomain is the PCI bus domain.
pciBus is the PCI bus identifier.
pciDevice is the PCI device identifier.
pciFunction is the PCI device function identifier.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PCI_BUS_INFO_PROPERTIES_EXT

To query properties of queues available on a physical device, call:

// Provided by VK_VERSION_1_0
void vkGetPhysicalDeviceQueueFamilyProperties(
    VkPhysicalDevice                            physicalDevice,
    uint32_t*                                   pQueueFamilyPropertyCount,
    VkQueueFamilyProperties*                    pQueueFamilyProperties);

physicalDevice is the handle to the physical device whose properties will be queried.
pQueueFamilyPropertyCount is a pointer to an integer related to the number of queue families available or queried, as described below.
pQueueFamilyProperties is either NULL or a pointer to an array of VkQueueFamilyProperties structures.

If pQueueFamilyProperties is NULL, then the number of queue families available is returned in pQueueFamilyPropertyCount. Implementations must support at least one queue family. Otherwise, pQueueFamilyPropertyCount must point to a variable set by the user to the number of elements in the pQueueFamilyProperties array, and on return the variable is overwritten with the number of structures actually written to pQueueFamilyProperties. If pQueueFamilyPropertyCount is less than the number of queue families available, at most pQueueFamilyPropertyCount structures will be written.

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pQueueFamilyPropertyCount must be a valid pointer to a uint32_t value
If the value referenced by pQueueFamilyPropertyCount is not 0, and pQueueFamilyProperties is not NULL, pQueueFamilyProperties must be a valid pointer to an array of pQueueFamilyPropertyCount VkQueueFamilyProperties structures

The VkQueueFamilyProperties structure is defined as:

// Provided by VK_VERSION_1_0
typedef struct VkQueueFamilyProperties {
    VkQueueFlags    queueFlags;
    uint32_t        queueCount;
    uint32_t        timestampValidBits;
    VkExtent3D      minImageTransferGranularity;
} VkQueueFamilyProperties;

queueFlags is a bitmask of VkQueueFlagBits indicating capabilities of the queues in this queue family.
queueCount is the unsigned integer count of queues in this queue family. Each queue family must support at least one queue.
timestampValidBits is the unsigned integer count of meaningful bits in the timestamps written via vkCmdWriteTimestamp. The valid range for the count is 36..64 bits, or a value of 0, indicating no support for timestamps. Bits outside the valid range are guaranteed to be zeros.
minImageTransferGranularity is the minimum granularity supported for image transfer operations on the queues in this queue family.

The value returned in minImageTransferGranularity has a unit of compressed texel blocks for images having a block-compressed format, and a unit of texels otherwise.

Possible values of minImageTransferGranularity are:

(0,0,0) which indicates that only whole mip levels must be transferred using the image transfer operations on the corresponding queues. In this case, the following restrictions apply to all offset and extent parameters of image transfer operations:
- The x, y, and z members of a VkOffset3D parameter must always be zero.
- The width, height, and depth members of a VkExtent3D parameter must always match the width, height, and depth of the image subresource corresponding to the parameter, respectively.
(A_x, A_y, A_z) where A_x, A_y, and A_z are all integer powers of two. In this case the following restrictions apply to all image transfer operations:
- x, y, and z of a VkOffset3D parameter must be integer multiples of A_x, A_y, and A_z, respectively.
- width of a VkExtent3D parameter must be an integer multiple of A_x, or else x + width must equal the width of the image subresource corresponding to the parameter.
- height of a VkExtent3D parameter must be an integer multiple of A_y, or else y + height must equal the height of the image subresource corresponding to the parameter.
- depth of a VkExtent3D parameter must be an integer multiple of A_z, or else z + depth must equal the depth of the image subresource corresponding to the parameter.
- If the format of the image corresponding to the parameters is one of the block-compressed formats then for the purposes of the above calculations the granularity must be scaled up by the compressed texel block dimensions.

Queues supporting graphics and/or compute operations must report (1,1,1) in minImageTransferGranularity, meaning that there are no additional restrictions on the granularity of image transfer operations for these queues. Other queues supporting image transfer operations are only required to support whole mip level transfers, thus minImageTransferGranularity for queues belonging to such queue families may be (0,0,0).

The Device Memory section describes memory properties queried from the physical device.

For physical device feature queries see the Features chapter.

Bits which may be set in VkQueueFamilyProperties::queueFlags indicating capabilities of queues in a queue family are:

// Provided by VK_VERSION_1_0
typedef enum VkQueueFlagBits {
    VK_QUEUE_GRAPHICS_BIT = 0x00000001,
    VK_QUEUE_COMPUTE_BIT = 0x00000002,
    VK_QUEUE_TRANSFER_BIT = 0x00000004,
    VK_QUEUE_SPARSE_BINDING_BIT = 0x00000008,
  // Provided by VK_VERSION_1_1
    VK_QUEUE_PROTECTED_BIT = 0x00000010,
} VkQueueFlagBits;

VK_QUEUE_GRAPHICS_BIT specifies that queues in this queue family support graphics operations.
VK_QUEUE_COMPUTE_BIT specifies that queues in this queue family support compute operations.
VK_QUEUE_TRANSFER_BIT specifies that queues in this queue family support transfer operations.
VK_QUEUE_SPARSE_BINDING_BIT specifies that queues in this queue family support sparse memory management operations (see Sparse Resources). If any of the sparse resource features are enabled, then at least one queue family must support this bit.
if VK_QUEUE_PROTECTED_BIT is set, then the queues in this queue family support the VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT bit. (see Protected Memory). If the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support this bit.

If an implementation exposes any queue family that supports graphics operations, at least one queue family of at least one physical device exposed by the implementation must support both graphics and compute operations.

Furthermore, if the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support graphics operations, compute operations, and protected memory operations.

Note

All commands that are allowed on a queue that supports transfer operations are also allowed on a queue that supports either graphics or compute operations. Thus, if the capabilities of a queue family include VK_QUEUE_GRAPHICS_BIT or VK_QUEUE_COMPUTE_BIT, then reporting the VK_QUEUE_TRANSFER_BIT capability separately for that queue family is optional.

For further details see Queues.

// Provided by VK_VERSION_1_0
typedef VkFlags VkQueueFlags;

VkQueueFlags is a bitmask type for setting a mask of zero or more VkQueueFlagBits.

To query properties of queues available on a physical device, call:

// Provided by VK_VERSION_1_1
void vkGetPhysicalDeviceQueueFamilyProperties2(
    VkPhysicalDevice                            physicalDevice,
    uint32_t*                                   pQueueFamilyPropertyCount,
    VkQueueFamilyProperties2*                   pQueueFamilyProperties);

or the equivalent command

// Provided by VK_KHR_get_physical_device_properties2
void vkGetPhysicalDeviceQueueFamilyProperties2KHR(
    VkPhysicalDevice                            physicalDevice,
    uint32_t*                                   pQueueFamilyPropertyCount,
    VkQueueFamilyProperties2*                   pQueueFamilyProperties);

physicalDevice is the handle to the physical device whose properties will be queried.
pQueueFamilyPropertyCount is a pointer to an integer related to the number of queue families available or queried, as described in vkGetPhysicalDeviceQueueFamilyProperties.
pQueueFamilyProperties is either NULL or a pointer to an array of VkQueueFamilyProperties2 structures.

vkGetPhysicalDeviceQueueFamilyProperties2 behaves similarly to vkGetPhysicalDeviceQueueFamilyProperties, with the ability to return extended information in a pNext chain of output structures.

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pQueueFamilyPropertyCount must be a valid pointer to a uint32_t value
If the value referenced by pQueueFamilyPropertyCount is not 0, and pQueueFamilyProperties is not NULL, pQueueFamilyProperties must be a valid pointer to an array of pQueueFamilyPropertyCount VkQueueFamilyProperties2 structures

The VkQueueFamilyProperties2 structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkQueueFamilyProperties2 {
    VkStructureType            sType;
    void*                      pNext;
    VkQueueFamilyProperties    queueFamilyProperties;
} VkQueueFamilyProperties2;

or the equivalent

// Provided by VK_KHR_get_physical_device_properties2
typedef VkQueueFamilyProperties2 VkQueueFamilyProperties2KHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
queueFamilyProperties is a VkQueueFamilyProperties structure which is populated with the same values as in vkGetPhysicalDeviceQueueFamilyProperties.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2
pNext must be NULL or a pointer to a valid instance of VkQueueFamilyCheckpointPropertiesNV
The sType value of each struct in the pNext chain must be unique

Additional queue family information can be queried by setting VkQueueFamilyProperties2::pNext to point to a VkQueueFamilyCheckpointPropertiesNV structure.

The VkQueueFamilyCheckpointPropertiesNV structure is defined as:

// Provided by VK_NV_device_diagnostic_checkpoints
typedef struct VkQueueFamilyCheckpointPropertiesNV {
    VkStructureType         sType;
    void*                   pNext;
    VkPipelineStageFlags    checkpointExecutionStageMask;
} VkQueueFamilyCheckpointPropertiesNV;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
checkpointExecutionStageMask is a mask indicating which pipeline stages the implementation can execute checkpoint markers in.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_QUEUE_FAMILY_CHECKPOINT_PROPERTIES_NV

To enumerate the performance query counters available on a queue family of a physical device, call:

// Provided by VK_KHR_performance_query
VkResult vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR(
    VkPhysicalDevice                            physicalDevice,
    uint32_t                                    queueFamilyIndex,
    uint32_t*                                   pCounterCount,
    VkPerformanceCounterKHR*                    pCounters,
    VkPerformanceCounterDescriptionKHR*         pCounterDescriptions);

physicalDevice is the handle to the physical device whose queue family performance query counter properties will be queried.
queueFamilyIndex is the index into the queue family of the physical device we want to get properties for.
pCounterCount is a pointer to an integer related to the number of counters available or queried, as described below.
pCounters is either NULL or a pointer to an array of VkPerformanceCounterKHR structures.
pCounterDescriptions is either NULL or a pointer to an array of VkPerformanceCounterDescriptionKHR structures.

If pCounters is NULL and pCounterDescriptions is NULL, then the number of counters available is returned in pCounterCount. Otherwise, pCounterCount must point to a variable set by the user to the number of elements in the pCounters, pCounterDescriptions, or both arrays and on return the variable is overwritten with the number of structures actually written out. If pCounterCount is less than the number of counters available, at most pCounterCount structures will be written and VK_INCOMPLETE will be returned instead of VK_SUCCESS.

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pCounterCount must be a valid pointer to a uint32_t value
If the value referenced by pCounterCount is not 0, and pCounters is not NULL, pCounters must be a valid pointer to an array of pCounterCount VkPerformanceCounterKHR structures
If the value referenced by pCounterCount is not 0, and pCounterDescriptions is not NULL, pCounterDescriptions must be a valid pointer to an array of pCounterCount VkPerformanceCounterDescriptionKHR structures

Return Codes

Success

VK_SUCCESS
VK_INCOMPLETE

Failure

VK_ERROR_OUT_OF_HOST_MEMORY
VK_ERROR_OUT_OF_DEVICE_MEMORY
VK_ERROR_INITIALIZATION_FAILED

The VkPerformanceCounterKHR structure is defined as:

// Provided by VK_KHR_performance_query
typedef struct VkPerformanceCounterKHR {
    VkStructureType                   sType;
    const void*                       pNext;
    VkPerformanceCounterUnitKHR       unit;
    VkPerformanceCounterScopeKHR      scope;
    VkPerformanceCounterStorageKHR    storage;
    uint8_t                           uuid[VK_UUID_SIZE];
} VkPerformanceCounterKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
unit is a VkPerformanceCounterUnitKHR specifying the unit that the counter data will record.
scope is a VkPerformanceCounterScopeKHR specifying the scope that the counter belongs to.
storage is a VkPerformanceCounterStorageKHR specifying the storage type that the counter’s data uses.
uuid is an array of size VK_UUID_SIZE, containing 8-bit values that represent a universally unique identifier for the counter of the physical device.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_KHR
pNext must be NULL

Performance counters have an associated unit. This unit describes how to interpret the performance counter result.

The performance counter unit types which may be returned in VkPerformanceCounterKHR::unit are:

// Provided by VK_KHR_performance_query
typedef enum VkPerformanceCounterUnitKHR {
    VK_PERFORMANCE_COUNTER_UNIT_GENERIC_KHR = 0,
    VK_PERFORMANCE_COUNTER_UNIT_PERCENTAGE_KHR = 1,
    VK_PERFORMANCE_COUNTER_UNIT_NANOSECONDS_KHR = 2,
    VK_PERFORMANCE_COUNTER_UNIT_BYTES_KHR = 3,
    VK_PERFORMANCE_COUNTER_UNIT_BYTES_PER_SECOND_KHR = 4,
    VK_PERFORMANCE_COUNTER_UNIT_KELVIN_KHR = 5,
    VK_PERFORMANCE_COUNTER_UNIT_WATTS_KHR = 6,
    VK_PERFORMANCE_COUNTER_UNIT_VOLTS_KHR = 7,
    VK_PERFORMANCE_COUNTER_UNIT_AMPS_KHR = 8,
    VK_PERFORMANCE_COUNTER_UNIT_HERTZ_KHR = 9,
    VK_PERFORMANCE_COUNTER_UNIT_CYCLES_KHR = 10,
} VkPerformanceCounterUnitKHR;

VK_PERFORMANCE_COUNTER_UNIT_GENERIC_KHR - the performance counter unit is a generic data point.
VK_PERFORMANCE_COUNTER_UNIT_PERCENTAGE_KHR - the performance counter unit is a percentage (%).
VK_PERFORMANCE_COUNTER_UNIT_NANOSECONDS_KHR - the performance counter unit is a value of nanoseconds (ns).
VK_PERFORMANCE_COUNTER_UNIT_BYTES_KHR - the performance counter unit is a value of bytes.
VK_PERFORMANCE_COUNTER_UNIT_BYTES_PER_SECOND_KHR - the performance counter unit is a value of bytes/s.
VK_PERFORMANCE_COUNTER_UNIT_KELVIN_KHR - the performance counter unit is a temperature reported in Kelvin.
VK_PERFORMANCE_COUNTER_UNIT_WATTS_KHR - the performance counter unit is a value of watts (W).
VK_PERFORMANCE_COUNTER_UNIT_VOLTS_KHR - the performance counter unit is a value of volts (V).
VK_PERFORMANCE_COUNTER_UNIT_AMPS_KHR - the performance counter unit is a value of amps (A).
VK_PERFORMANCE_COUNTER_UNIT_HERTZ_KHR - the performance counter unit is a value of hertz (Hz).
VK_PERFORMANCE_COUNTER_UNIT_CYCLES_KHR - the performance counter unit is a value of cycles.

Performance counters have an associated scope. This scope describes the granularity of a performance counter.

The performance counter scope types which may be returned in VkPerformanceCounterKHR::scope are:

// Provided by VK_KHR_performance_query
typedef enum VkPerformanceCounterScopeKHR {
    VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR = 0,
    VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR = 1,
    VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR = 2,
    VK_QUERY_SCOPE_COMMAND_BUFFER_KHR = VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR,
    VK_QUERY_SCOPE_RENDER_PASS_KHR = VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR,
    VK_QUERY_SCOPE_COMMAND_KHR = VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR,
} VkPerformanceCounterScopeKHR;

VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR - the performance counter scope is a single complete command buffer.
VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR - the performance counter scope is zero or more complete render passes. The performance query containing the performance counter must begin and end outside a render pass instance.
VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR - the performance counter scope is zero or more commands.

Performance counters have an associated storage. This storage describes the payload of a counter result.

The performance counter storage types which may be returned in VkPerformanceCounterKHR::storage are:

// Provided by VK_KHR_performance_query
typedef enum VkPerformanceCounterStorageKHR {
    VK_PERFORMANCE_COUNTER_STORAGE_INT32_KHR = 0,
    VK_PERFORMANCE_COUNTER_STORAGE_INT64_KHR = 1,
    VK_PERFORMANCE_COUNTER_STORAGE_UINT32_KHR = 2,
    VK_PERFORMANCE_COUNTER_STORAGE_UINT64_KHR = 3,
    VK_PERFORMANCE_COUNTER_STORAGE_FLOAT32_KHR = 4,
    VK_PERFORMANCE_COUNTER_STORAGE_FLOAT64_KHR = 5,
} VkPerformanceCounterStorageKHR;

VK_PERFORMANCE_COUNTER_STORAGE_INT32_KHR - the performance counter storage is a 32-bit signed integer.
VK_PERFORMANCE_COUNTER_STORAGE_INT64_KHR - the performance counter storage is a 64-bit signed integer.
VK_PERFORMANCE_COUNTER_STORAGE_UINT32_KHR - the performance counter storage is a 32-bit unsigned integer.
VK_PERFORMANCE_COUNTER_STORAGE_UINT64_KHR - the performance counter storage is a 64-bit unsigned integer.
VK_PERFORMANCE_COUNTER_STORAGE_FLOAT32_KHR - the performance counter storage is a 32-bit floating-point.
VK_PERFORMANCE_COUNTER_STORAGE_FLOAT64_KHR - the performance counter storage is a 64-bit floating-point.

The VkPerformanceCounterDescriptionKHR structure is defined as:

// Provided by VK_KHR_performance_query
typedef struct VkPerformanceCounterDescriptionKHR {
    VkStructureType                            sType;
    const void*                                pNext;
    VkPerformanceCounterDescriptionFlagsKHR    flags;
    char                                       name[VK_MAX_DESCRIPTION_SIZE];
    char                                       category[VK_MAX_DESCRIPTION_SIZE];
    char                                       description[VK_MAX_DESCRIPTION_SIZE];
} VkPerformanceCounterDescriptionKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
flags is a bitmask of VkPerformanceCounterDescriptionFlagBitsKHR indicating the usage behavior for the counter.
name is an array of size VK_MAX_DESCRIPTION_SIZE, containing a null-terminated UTF-8 string specifying the name of the counter.
category is an array of size VK_MAX_DESCRIPTION_SIZE, containing a null-terminated UTF-8 string specifying the category of the counter.
description is an array of size VK_MAX_DESCRIPTION_SIZE, containing a null-terminated UTF-8 string specifying the description of the counter.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_DESCRIPTION_KHR
pNext must be NULL

Bits which can be set in VkPerformanceCounterDescriptionKHR::flags to specify usage behavior for a command pool are:

// Provided by VK_KHR_performance_query
typedef enum VkPerformanceCounterDescriptionFlagBitsKHR {
    VK_PERFORMANCE_COUNTER_DESCRIPTION_PERFORMANCE_IMPACTING_KHR = 0x00000001,
    VK_PERFORMANCE_COUNTER_DESCRIPTION_CONCURRENTLY_IMPACTED_KHR = 0x00000002,
} VkPerformanceCounterDescriptionFlagBitsKHR;

VK_PERFORMANCE_COUNTER_DESCRIPTION_PERFORMANCE_IMPACTING_KHR specifies that recording the counter may have a noticeable performance impact.
VK_PERFORMANCE_COUNTER_DESCRIPTION_CONCURRENTLY_IMPACTED_KHR specifies that concurrently recording the counter while other submitted command buffers are running may impact the accuracy of the recording.

// Provided by VK_KHR_performance_query
typedef VkFlags VkPerformanceCounterDescriptionFlagsKHR;

VkPerformanceCounterDescriptionFlagsKHR is a bitmask type for setting a mask of zero or more VkPerformanceCounterDescriptionFlagBitsKHR.

4.2. Devices

Device objects represent logical connections to physical devices. Each device exposes a number of queue families each having one or more queues. All queues in a queue family support the same operations.

As described in Physical Devices, a Vulkan application will first query for all physical devices in a system. Each physical device can then be queried for its capabilities, including its queue and queue family properties. Once an acceptable physical device is identified, an application will create a corresponding logical device. An application must create a separate logical device for each physical device it will use. The created logical device is then the primary interface to the physical device.

How to enumerate the physical devices in a system and query those physical devices for their queue family properties is described in the Physical Device Enumeration section above.

A single logical device can also be created from multiple physical devices, if those physical devices belong to the same device group. A device group is a set of physical devices that support accessing each other’s memory and recording a single command buffer that can be executed on all the physical devices. Device groups are enumerated by calling vkEnumeratePhysicalDeviceGroups, and a logical device is created from a subset of the physical devices in a device group by passing the physical devices through VkDeviceGroupDeviceCreateInfo. For two physical devices to be in the same device group, they must support identical extensions, features, and properties.

Note

Physical devices in the same device group must be so similar because there are no rules for how different features/properties would interact. They must return the same values for nearly every invariant vkGetPhysicalDevice* feature, property, capability, etc., but could potentially differ for certain queries based on things like having a different display connected, or different compositor, etc.. The specification does not attempt to enumerate which state is in each category, because such a list would quickly become out of date.

To retrieve a list of the device groups present in the system, call:

// Provided by VK_VERSION_1_1
VkResult vkEnumeratePhysicalDeviceGroups(
    VkInstance                                  instance,
    uint32_t*                                   pPhysicalDeviceGroupCount,
    VkPhysicalDeviceGroupProperties*            pPhysicalDeviceGroupProperties);

or the equivalent command

// Provided by VK_KHR_device_group_creation
VkResult vkEnumeratePhysicalDeviceGroupsKHR(
    VkInstance                                  instance,
    uint32_t*                                   pPhysicalDeviceGroupCount,
    VkPhysicalDeviceGroupProperties*            pPhysicalDeviceGroupProperties);

instance is a handle to a Vulkan instance previously created with vkCreateInstance.
pPhysicalDeviceGroupCount is a pointer to an integer related to the number of device groups available or queried, as described below.
pPhysicalDeviceGroupProperties is either NULL or a pointer to an array of VkPhysicalDeviceGroupProperties structures.

If pPhysicalDeviceGroupProperties is NULL, then the number of device groups available is returned in pPhysicalDeviceGroupCount. Otherwise, pPhysicalDeviceGroupCount must point to a variable set by the user to the number of elements in the pPhysicalDeviceGroupProperties array, and on return the variable is overwritten with the number of structures actually written to pPhysicalDeviceGroupProperties. If pPhysicalDeviceGroupCount is less than the number of device groups available, at most pPhysicalDeviceGroupCount structures will be written. If pPhysicalDeviceGroupCount is smaller than the number of device groups available, VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available device groups were returned.

Every physical device must be in exactly one device group.

Valid Usage (Implicit)

instance must be a valid VkInstance handle
pPhysicalDeviceGroupCount must be a valid pointer to a uint32_t value
If the value referenced by pPhysicalDeviceGroupCount is not 0, and pPhysicalDeviceGroupProperties is not NULL, pPhysicalDeviceGroupProperties must be a valid pointer to an array of pPhysicalDeviceGroupCount VkPhysicalDeviceGroupProperties structures

Return Codes

Success

VK_SUCCESS
VK_INCOMPLETE

Failure

VK_ERROR_OUT_OF_HOST_MEMORY
VK_ERROR_OUT_OF_DEVICE_MEMORY
VK_ERROR_INITIALIZATION_FAILED

The VkPhysicalDeviceGroupProperties structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkPhysicalDeviceGroupProperties {
    VkStructureType     sType;
    void*               pNext;
    uint32_t            physicalDeviceCount;
    VkPhysicalDevice    physicalDevices[VK_MAX_DEVICE_GROUP_SIZE];
    VkBool32            subsetAllocation;
} VkPhysicalDeviceGroupProperties;

or the equivalent

// Provided by VK_KHR_device_group_creation
typedef VkPhysicalDeviceGroupProperties VkPhysicalDeviceGroupPropertiesKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
physicalDeviceCount is the number of physical devices in the group.
physicalDevices is an array of VK_MAX_DEVICE_GROUP_SIZE VkPhysicalDevice handles representing all physical devices in the group. The first physicalDeviceCount elements of the array will be valid.
subsetAllocation specifies whether logical devices created from the group support allocating device memory on a subset of devices, via the deviceMask member of the VkMemoryAllocateFlagsInfo. If this is VK_FALSE, then all device memory allocations are made across all physical devices in the group. If physicalDeviceCount is 1, then subsetAllocation must be VK_FALSE.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES
pNext must be NULL

4.2.1. Device Creation

Logical devices are represented by VkDevice handles:

// Provided by VK_VERSION_1_0
VK_DEFINE_HANDLE(VkDevice)

A logical device is created as a connection to a physical device. To create a logical device, call:

// Provided by VK_VERSION_1_0
VkResult vkCreateDevice(
    VkPhysicalDevice                            physicalDevice,
    const VkDeviceCreateInfo*                   pCreateInfo,
    const VkAllocationCallbacks*                pAllocator,
    VkDevice*                                   pDevice);

physicalDevice must be one of the device handles returned from a call to vkEnumeratePhysicalDevices (see Physical Device Enumeration).
pCreateInfo is a pointer to a VkDeviceCreateInfo structure containing information about how to create the device.
pAllocator controls host memory allocation as described in the Memory Allocation chapter.
pDevice is a pointer to a handle in which the created VkDevice is returned.

vkCreateDevice verifies that extensions and features requested in the ppEnabledExtensionNames and pEnabledFeatures members of pCreateInfo, respectively, are supported by the implementation. If any requested extension is not supported, vkCreateDevice must return VK_ERROR_EXTENSION_NOT_PRESENT. If any requested feature is not supported, vkCreateDevice must return VK_ERROR_FEATURE_NOT_PRESENT. Support for extensions can be checked before creating a device by querying vkEnumerateDeviceExtensionProperties. Support for features can similarly be checked by querying vkGetPhysicalDeviceFeatures.

After verifying and enabling the extensions the VkDevice object is created and returned to the application. If a requested extension is only supported by a layer, both the layer and the extension need to be specified at vkCreateInstance time for the creation to succeed.

Multiple logical devices can be created from the same physical device. Logical device creation may fail due to lack of device-specific resources (in addition to the other errors). If that occurs, vkCreateDevice will return VK_ERROR_TOO_MANY_OBJECTS.

Valid Usage

All required extensions for each extension in the VkDeviceCreateInfo::ppEnabledExtensionNames list must also be present in that list

Valid Usage (Implicit)

physicalDevice must be a valid VkPhysicalDevice handle
pCreateInfo must be a valid pointer to a valid VkDeviceCreateInfo structure
If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure
pDevice must be a valid pointer to a VkDevice handle

Return Codes

Success

VK_SUCCESS

Failure

VK_ERROR_OUT_OF_HOST_MEMORY
VK_ERROR_OUT_OF_DEVICE_MEMORY
VK_ERROR_INITIALIZATION_FAILED
VK_ERROR_EXTENSION_NOT_PRESENT
VK_ERROR_FEATURE_NOT_PRESENT
VK_ERROR_TOO_MANY_OBJECTS
VK_ERROR_DEVICE_LOST

The VkDeviceCreateInfo structure is defined as:

// Provided by VK_VERSION_1_0
typedef struct VkDeviceCreateInfo {
    VkStructureType                    sType;
    const void*                        pNext;
    VkDeviceCreateFlags                flags;
    uint32_t                           queueCreateInfoCount;
    const VkDeviceQueueCreateInfo*     pQueueCreateInfos;
    uint32_t                           enabledLayerCount;
    const char* const*                 ppEnabledLayerNames;
    uint32_t                           enabledExtensionCount;
    const char* const*                 ppEnabledExtensionNames;
    const VkPhysicalDeviceFeatures*    pEnabledFeatures;
} VkDeviceCreateInfo;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
flags is reserved for future use.
queueCreateInfoCount is the unsigned integer size of the pQueueCreateInfos array. Refer to the Queue Creation section below for further details.
pQueueCreateInfos is a pointer to an array of VkDeviceQueueCreateInfo structures describing the queues that are requested to be created along with the logical device. Refer to the Queue Creation section below for further details.
enabledLayerCount is deprecated and ignored.
ppEnabledLayerNames is deprecated and ignored. See Device Layer Deprecation.
enabledExtensionCount is the number of device extensions to enable.
ppEnabledExtensionNames is a pointer to an array of enabledExtensionCount null-terminated UTF-8 strings containing the names of extensions to enable for the created device. See the Extensions section for further details.
pEnabledFeatures is NULL or a pointer to a VkPhysicalDeviceFeatures structure containing boolean indicators of all the features to be enabled. Refer to the Features section for further details.

Valid Usage

The queueFamilyIndex member of each element of pQueueCreateInfos must be unique within pQueueCreateInfos, except that two members can share the same queueFamilyIndex if one is a protected-capable queue and one is not a protected-capable queue
If the pNext chain includes a VkPhysicalDeviceFeatures2 structure, then pEnabledFeatures must be NULL
ppEnabledExtensionNames must not contain VK_AMD_negative_viewport_height
ppEnabledExtensionNames must not contain both VK_KHR_buffer_device_address and VK_EXT_buffer_device_address
If the pNext chain includes a VkPhysicalDeviceVulkan11Features structure, then it must not include a VkPhysicalDevice16BitStorageFeatures, VkPhysicalDeviceMultiviewFeatures, VkPhysicalDeviceVariablePointersFeatures, VkPhysicalDeviceProtectedMemoryFeatures, VkPhysicalDeviceSamplerYcbcrConversionFeatures, or VkPhysicalDeviceShaderDrawParametersFeatures structure
If the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then it must not include a VkPhysicalDevice8BitStorageFeatures, VkPhysicalDeviceShaderAtomicInt64Features, VkPhysicalDeviceShaderFloat16Int8Features, VkPhysicalDeviceDescriptorIndexingFeatures, VkPhysicalDeviceScalarBlockLayoutFeatures, VkPhysicalDeviceImagelessFramebufferFeatures, VkPhysicalDeviceUniformBufferStandardLayoutFeatures, VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures, VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures, VkPhysicalDeviceHostQueryResetFeatures, VkPhysicalDeviceTimelineSemaphoreFeatures, VkPhysicalDeviceBufferDeviceAddressFeatures, or VkPhysicalDeviceVulkanMemoryModelFeatures structure
If ppEnabledExtensions contains "VK_KHR_draw_indirect_count" and the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then VkPhysicalDeviceVulkan12Features::drawIndirectCount must be VK_TRUE
If ppEnabledExtensions contains "VK_KHR_sampler_mirror_clamp_to_edge" and the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then VkPhysicalDeviceVulkan12Features::samplerMirrorClampToEdge must be VK_TRUE
If ppEnabledExtensions contains "VK_EXT_descriptor_indexing" and the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then VkPhysicalDeviceVulkan12Features::descriptorIndexing must be VK_TRUE
If ppEnabledExtensions contains "VK_EXT_sampler_filter_minmax" and the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then VkPhysicalDeviceVulkan12Features::samplerFilterMinmax must be VK_TRUE
If ppEnabledExtensions contains "VK_EXT_shader_viewport_index_layer" and the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then VkPhysicalDeviceVulkan12Features::shaderOutputViewportIndex and VkPhysicalDeviceVulkan12Features::shaderOutputLayer must both be VK_TRUE

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO
Each pNext member of any structure (including this one) in the pNext chain must be either NULL or a pointer to a valid instance of VkDeviceDiagnosticsConfigCreateInfoNV, VkDeviceGroupDeviceCreateInfo, VkDeviceMemoryOverallocationCreateInfoAMD, VkDevicePrivateDataCreateInfoEXT, VkPhysicalDevice16BitStorageFeatures, VkPhysicalDevice8BitStorageFeatures, VkPhysicalDeviceASTCDecodeFeaturesEXT, VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT, VkPhysicalDeviceBufferDeviceAddressFeatures, VkPhysicalDeviceBufferDeviceAddressFeaturesEXT, VkPhysicalDeviceCoherentMemoryFeaturesAMD, VkPhysicalDeviceComputeShaderDerivativesFeaturesNV, VkPhysicalDeviceConditionalRenderingFeaturesEXT, VkPhysicalDeviceCooperativeMatrixFeaturesNV, VkPhysicalDeviceCornerSampledImageFeaturesNV, VkPhysicalDeviceCoverageReductionModeFeaturesNV, VkPhysicalDeviceCustomBorderColorFeaturesEXT, VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV, VkPhysicalDeviceDepthClipEnableFeaturesEXT, VkPhysicalDeviceDescriptorIndexingFeatures, VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV, VkPhysicalDeviceDiagnosticsConfigFeaturesNV, VkPhysicalDeviceExclusiveScissorFeaturesNV, VkPhysicalDeviceExtendedDynamicStateFeaturesEXT, VkPhysicalDeviceFeatures2, VkPhysicalDeviceFragmentDensityMap2FeaturesEXT, VkPhysicalDeviceFragmentDensityMapFeaturesEXT, VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV, VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT, VkPhysicalDeviceHostQueryResetFeatures, VkPhysicalDeviceImageRobustnessFeaturesEXT, VkPhysicalDeviceImagelessFramebufferFeatures, VkPhysicalDeviceIndexTypeUint8FeaturesEXT, VkPhysicalDeviceInlineUniformBlockFeaturesEXT, VkPhysicalDeviceLineRasterizationFeaturesEXT, VkPhysicalDeviceMemoryPriorityFeaturesEXT, VkPhysicalDeviceMeshShaderFeaturesNV, VkPhysicalDeviceMultiviewFeatures, VkPhysicalDevicePerformanceQueryFeaturesKHR, VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT, VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR, VkPhysicalDevicePrivateDataFeaturesEXT, VkPhysicalDeviceProtectedMemoryFeatures, VkPhysicalDeviceRayTracingFeaturesKHR, VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV, VkPhysicalDeviceRobustness2FeaturesEXT, VkPhysicalDeviceSamplerYcbcrConversionFeatures, VkPhysicalDeviceScalarBlockLayoutFeatures, VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures, VkPhysicalDeviceShaderAtomicFloatFeaturesEXT, VkPhysicalDeviceShaderAtomicInt64Features, VkPhysicalDeviceShaderClockFeaturesKHR, VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT, VkPhysicalDeviceShaderDrawParametersFeatures, VkPhysicalDeviceShaderFloat16Int8Features, VkPhysicalDeviceShaderImageFootprintFeaturesNV, VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL, VkPhysicalDeviceShaderSMBuiltinsFeaturesNV, VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures, VkPhysicalDeviceShadingRateImageFeaturesNV, VkPhysicalDeviceSubgroupSizeControlFeaturesEXT, VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT, VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT, VkPhysicalDeviceTimelineSemaphoreFeatures, VkPhysicalDeviceTransformFeedbackFeaturesEXT, VkPhysicalDeviceUniformBufferStandardLayoutFeatures, VkPhysicalDeviceVariablePointersFeatures, VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT, VkPhysicalDeviceVulkan11Features, VkPhysicalDeviceVulkan12Features, VkPhysicalDeviceVulkanMemoryModelFeatures, or VkPhysicalDeviceYcbcrImageArraysFeaturesEXT
The sType value of each struct in the pNext chain must be unique, with the exception of structures of type VkDevicePrivateDataCreateInfoEXT
flags must be 0
pQueueCreateInfos must be a valid pointer to an array of queueCreateInfoCount valid VkDeviceQueueCreateInfo structures
If enabledLayerCount is not 0, ppEnabledLayerNames must be a valid pointer to an array of enabledLayerCount null-terminated UTF-8 strings
If enabledExtensionCount is not 0, ppEnabledExtensionNames must be a valid pointer to an array of enabledExtensionCount null-terminated UTF-8 strings
If pEnabledFeatures is not NULL, pEnabledFeatures must be a valid pointer to a valid VkPhysicalDeviceFeatures structure
queueCreateInfoCount must be greater than 0

// Provided by VK_VERSION_1_0
typedef VkFlags VkDeviceCreateFlags;

VkDeviceCreateFlags is a bitmask type for setting a mask, but is currently reserved for future use.

A logical device can be created that connects to one or more physical devices by adding a VkDeviceGroupDeviceCreateInfo structure to the pNext chain of VkDeviceCreateInfo. The VkDeviceGroupDeviceCreateInfo structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkDeviceGroupDeviceCreateInfo {
    VkStructureType            sType;
    const void*                pNext;
    uint32_t                   physicalDeviceCount;
    const VkPhysicalDevice*    pPhysicalDevices;
} VkDeviceGroupDeviceCreateInfo;

or the equivalent

// Provided by VK_KHR_device_group_creation
typedef VkDeviceGroupDeviceCreateInfo VkDeviceGroupDeviceCreateInfoKHR;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
physicalDeviceCount is the number of elements in the pPhysicalDevices array.
pPhysicalDevices is a pointer to an array of physical device handles belonging to the same device group.

The elements of the pPhysicalDevices array are an ordered list of the physical devices that the logical device represents. These must be a subset of a single device group, and need not be in the same order as they were enumerated. The order of the physical devices in the pPhysicalDevices array determines the device index of each physical device, with element i being assigned a device index of i. Certain commands and structures refer to one or more physical devices by using device indices or device masks formed using device indices.

A logical device created without using VkDeviceGroupDeviceCreateInfo, or with physicalDeviceCount equal to zero, is equivalent to a physicalDeviceCount of one and pPhysicalDevices pointing to the physicalDevice parameter to vkCreateDevice. In particular, the device index of that physical device is zero.

Valid Usage

Each element of pPhysicalDevices must be unique
All elements of pPhysicalDevices must be in the same device group as enumerated by vkEnumeratePhysicalDeviceGroups
If physicalDeviceCount is not 0, the physicalDevice parameter of vkCreateDevice must be an element of pPhysicalDevices

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO
If physicalDeviceCount is not 0, pPhysicalDevices must be a valid pointer to an array of physicalDeviceCount valid VkPhysicalDevice handles

To specify whether device memory allocation is allowed beyond the size reported by VkPhysicalDeviceMemoryProperties, add a VkDeviceMemoryOverallocationCreateInfoAMD structure to the pNext chain of the VkDeviceCreateInfo structure. If this structure is not specified, it is as if the VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD value is used.

// Provided by VK_AMD_memory_overallocation_behavior
typedef struct VkDeviceMemoryOverallocationCreateInfoAMD {
    VkStructureType                      sType;
    const void*                          pNext;
    VkMemoryOverallocationBehaviorAMD    overallocationBehavior;
} VkDeviceMemoryOverallocationCreateInfoAMD;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
overallocationBehavior is the desired overallocation behavior.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_MEMORY_OVERALLOCATION_CREATE_INFO_AMD
overallocationBehavior must be a valid VkMemoryOverallocationBehaviorAMD value

Possible values for VkDeviceMemoryOverallocationCreateInfoAMD::overallocationBehavior include:

// Provided by VK_AMD_memory_overallocation_behavior
typedef enum VkMemoryOverallocationBehaviorAMD {
    VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD = 0,
    VK_MEMORY_OVERALLOCATION_BEHAVIOR_ALLOWED_AMD = 1,
    VK_MEMORY_OVERALLOCATION_BEHAVIOR_DISALLOWED_AMD = 2,
} VkMemoryOverallocationBehaviorAMD;

VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD lets the implementation decide if overallocation is allowed.
VK_MEMORY_OVERALLOCATION_BEHAVIOR_ALLOWED_AMD specifies overallocation is allowed if platform permits.
VK_MEMORY_OVERALLOCATION_BEHAVIOR_DISALLOWED_AMD specifies the application is not allowed to allocate device memory beyond the heap sizes reported by VkPhysicalDeviceMemoryProperties. Allocations that are not explicitly made by the application within the scope of the Vulkan instance are not accounted for.

When using the Nsight^™ Aftermath SDK, to configure how device crash dumps are created, add a VkDeviceDiagnosticsConfigCreateInfoNV structure to the pNext chain of the VkDeviceCreateInfo structure.

// Provided by VK_NV_device_diagnostics_config
typedef struct VkDeviceDiagnosticsConfigCreateInfoNV {
    VkStructureType                     sType;
    const void*                         pNext;
    VkDeviceDiagnosticsConfigFlagsNV    flags;
} VkDeviceDiagnosticsConfigCreateInfoNV;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
flags is a bitmask of VkDeviceDiagnosticsConfigFlagBitsNV specifying addtional parameters for configuring diagnostic tools.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_DIAGNOSTICS_CONFIG_CREATE_INFO_NV
flags must be a valid combination of VkDeviceDiagnosticsConfigFlagBitsNV values

Bits which can be set in VkDeviceDiagnosticsConfigCreateInfoNV::flags include:

// Provided by VK_NV_device_diagnostics_config
typedef enum VkDeviceDiagnosticsConfigFlagBitsNV {
    VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_SHADER_DEBUG_INFO_BIT_NV = 0x00000001,
    VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_RESOURCE_TRACKING_BIT_NV = 0x00000002,
    VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_AUTOMATIC_CHECKPOINTS_BIT_NV = 0x00000004,
} VkDeviceDiagnosticsConfigFlagBitsNV;

VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_SHADER_DEBUG_INFO_BIT_NV enables the generation of debug information for shaders.
VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_RESOURCE_TRACKING_BIT_NV enables driver side tracking of resources (images, buffers, etc.) used to augment the device fault information.
VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_AUTOMATIC_CHECKPOINTS_BIT_NV enables automatic insertion of diagnostic checkpoints for draw calls, dispatches, trace rays, and copies. The CPU call stack at the time of the command will be associated as the marker data for the automatically inserted checkpoints.

// Provided by VK_NV_device_diagnostics_config
typedef VkFlags VkDeviceDiagnosticsConfigFlagsNV;

VkDeviceDiagnosticsConfigFlagsNV is a bitmask type for setting a mask of zero or more VkDeviceDiagnosticsConfigFlagBitsNV.

To reserve private data storage slots, add a VkDevicePrivateDataCreateInfoEXT structure to the pNext chain of the VkDeviceCreateInfo structure. Reserving slots in this manner is not strictly necessary, but doing so may improve performance.

// Provided by VK_EXT_private_data
typedef struct VkDevicePrivateDataCreateInfoEXT {
    VkStructureType    sType;
    const void*        pNext;
    uint32_t           privateDataSlotRequestCount;
} VkDevicePrivateDataCreateInfoEXT;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
privateDataSlotRequestCount is the amount of slots to reserve.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_PRIVATE_DATA_CREATE_INFO_EXT

4.2.2. Device Use

The following is a high-level list of VkDevice uses along with references on where to find more information:

Creation of queues. See the Queues section below for further details.
Creation and tracking of various synchronization constructs. See Synchronization and Cache Control for further details.
Allocating, freeing, and managing memory. See Memory Allocation and Resource Creation for further details.
Creation and destruction of command buffers and command buffer pools. See Command Buffers for further details.
Creation, destruction, and management of graphics state. See Pipelines and Resource Descriptors, among others, for further details.

4.2.3. Lost Device

A logical device may become lost for a number of implementation-specific reasons, indicating that pending and future command execution may fail and cause resources and backing memory to become undefined.

Note

Typical reasons for device loss will include things like execution timing out (to prevent denial of service), power management events, platform resource management, implementation errors.

Applications not adhering to valid usage may also result in device loss being reported, however this is not guaranteed. Even if device loss is reported, the system may be in an unrecoverable state, and further usage of the API is still considered invalid.

When this happens, certain commands will return VK_ERROR_DEVICE_LOST. After any such event, the logical device is considered lost. It is not possible to reset the logical device to a non-lost state, however the lost state is specific to a logical device (VkDevice), and the corresponding physical device (VkPhysicalDevice) may be otherwise unaffected.

In some cases, the physical device may also be lost, and attempting to create a new logical device will fail, returning VK_ERROR_DEVICE_LOST. This is usually indicative of a problem with the underlying implementation, or its connection to the host. If the physical device has not been lost, and a new logical device is successfully created from that physical device, it must be in the non-lost state.

Note

Whilst logical device loss may be recoverable, in the case of physical device loss, it is unlikely that an application will be able to recover unless additional, unaffected physical devices exist on the system. The error is largely informational and intended only to inform the user that a platform issue has occurred, and should be investigated further. For example, underlying hardware may have developed a fault or become physically disconnected from the rest of the system. In many cases, physical device loss may cause other more serious issues such as the operating system crashing; in which case it may not be reported via the Vulkan API.

When a device is lost, its child objects are not implicitly destroyed and their handles are still valid. Those objects must still be destroyed before their parents or the device can be destroyed (see the Object Lifetime section). The host address space corresponding to device memory mapped using vkMapMemory is still valid, and host memory accesses to these mapped regions are still valid, but the contents are undefined. It is still legal to call any API command on the device and child objects.

Once a device is lost, command execution may fail, and commands that return a VkResult may return VK_ERROR_DEVICE_LOST. Commands that do not allow runtime errors must still operate correctly for valid usage and, if applicable, return valid data.

Commands that wait indefinitely for device execution (namely vkDeviceWaitIdle, vkQueueWaitIdle, vkWaitForFences or vkAcquireNextImageKHR with a maximum timeout, and vkGetQueryPoolResults with the VK_QUERY_RESULT_WAIT_BIT bit set in flags) must return in finite time even in the case of a lost device, and return either VK_SUCCESS or VK_ERROR_DEVICE_LOST. For any command that may return VK_ERROR_DEVICE_LOST, for the purpose of determining whether a command buffer is in the pending state, or whether resources are considered in-use by the device, a return value of VK_ERROR_DEVICE_LOST is equivalent to VK_SUCCESS.

The content of any external memory objects that have been exported from or imported to a lost device become undefined. Objects on other logical devices or in other APIs which are associated with the same underlying memory resource as the external memory objects on the lost device are unaffected other than their content becoming undefined. The layout of subresources of images on other logical devices that are bound to VkDeviceMemory objects associated with the same underlying memory resources as external memory objects on the lost device becomes VK_IMAGE_LAYOUT_UNDEFINED.

The state of VkSemaphore objects on other logical devices created by importing a semaphore payload with temporary permanence which was exported from the lost device is undefined. The state of VkSemaphore objects on other logical devices that permanently share a semaphore payload with a VkSemaphore object on the lost device is undefined, and remains undefined following any subsequent signal operations. Implementations must ensure pending and subsequently submitted wait operations on such semaphores behave as defined in Semaphore State Requirements For Wait Operations for external semaphores not in a valid state for a wait operation.

editing-note

TODO (piman) - I do not think we are very clear about what “in-use by the device” means.

4.2.4. Device Destruction

To destroy a device, call:

// Provided by VK_VERSION_1_0
void vkDestroyDevice(
    VkDevice                                    device,
    const VkAllocationCallbacks*                pAllocator);

device is the logical device to destroy.
pAllocator controls host memory allocation as described in the Memory Allocation chapter.

To ensure that no work is active on the device, vkDeviceWaitIdle can be used to gate the destruction of the device. Prior to destroying a device, an application is responsible for destroying/freeing any Vulkan objects that were created using that device as the first parameter of the corresponding vkCreate* or vkAllocate* command.

Note

The lifetime of each of these objects is bound by the lifetime of the VkDevice object. Therefore, to avoid resource leaks, it is critical that an application explicitly free all of these resources prior to calling vkDestroyDevice.

Valid Usage

All child objects created on device must have been destroyed prior to destroying device
If VkAllocationCallbacks were provided when device was created, a compatible set of callbacks must be provided here
If no VkAllocationCallbacks were provided when device was created, pAllocator must be NULL

Valid Usage (Implicit)

If device is not NULL, device must be a valid VkDevice handle
If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

Host Synchronization

Host access to device must be externally synchronized
Host access to all VkQueue objects received from device must be externally synchronized

4.3. Queues

4.3.1. Queue Family Properties

As discussed in the Physical Device Enumeration section above, the vkGetPhysicalDeviceQueueFamilyProperties command is used to retrieve details about the queue families and queues supported by a device.

Each index in the pQueueFamilyProperties array returned by vkGetPhysicalDeviceQueueFamilyProperties describes a unique queue family on that physical device. These indices are used when creating queues, and they correspond directly with the queueFamilyIndex that is passed to the vkCreateDevice command via the VkDeviceQueueCreateInfo structure as described in the Queue Creation section below.

Grouping of queue families within a physical device is implementation-dependent.

Note

The general expectation is that a physical device groups all queues of matching capabilities into a single family. However, while implementations should do this, it is possible that a physical device may return two separate queue families with the same capabilities.

Once an application has identified a physical device with the queue(s) that it desires to use, it will create those queues in conjunction with a logical device. This is described in the following section.

4.3.2. Queue Creation

Creating a logical device also creates the queues associated with that device. The queues to create are described by a set of VkDeviceQueueCreateInfo structures that are passed to vkCreateDevice in pQueueCreateInfos.

Queues are represented by VkQueue handles:

// Provided by VK_VERSION_1_0
VK_DEFINE_HANDLE(VkQueue)

The VkDeviceQueueCreateInfo structure is defined as:

// Provided by VK_VERSION_1_0
typedef struct VkDeviceQueueCreateInfo {
    VkStructureType             sType;
    const void*                 pNext;
    VkDeviceQueueCreateFlags    flags;
    uint32_t                    queueFamilyIndex;
    uint32_t                    queueCount;
    const float*                pQueuePriorities;
} VkDeviceQueueCreateInfo;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
flags is a bitmask indicating behavior of the queue.
queueFamilyIndex is an unsigned integer indicating the index of the queue family to create on this device. This index corresponds to the index of an element of the pQueueFamilyProperties array that was returned by vkGetPhysicalDeviceQueueFamilyProperties.
queueCount is an unsigned integer specifying the number of queues to create in the queue family indicated by queueFamilyIndex.
pQueuePriorities is a pointer to an array of queueCount normalized floating point values, specifying priorities of work that will be submitted to each created queue. See Queue Priority for more information.

Valid Usage

queueFamilyIndex must be less than pQueueFamilyPropertyCount returned by vkGetPhysicalDeviceQueueFamilyProperties
queueCount must be less than or equal to the queueCount member of the VkQueueFamilyProperties structure, as returned by vkGetPhysicalDeviceQueueFamilyProperties in the pQueueFamilyProperties[queueFamilyIndex]
Each element of pQueuePriorities must be between 0.0 and 1.0 inclusive
If the protected memory feature is not enabled, the VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT bit of flags must not be set

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO
pNext must be NULL or a pointer to a valid instance of VkDeviceQueueGlobalPriorityCreateInfoEXT
The sType value of each struct in the pNext chain must be unique
flags must be a valid combination of VkDeviceQueueCreateFlagBits values
pQueuePriorities must be a valid pointer to an array of queueCount float values
queueCount must be greater than 0

Bits which can be set in VkDeviceQueueCreateInfo::flags to specify usage behavior of the queue are:

// Provided by VK_VERSION_1_0
typedef enum VkDeviceQueueCreateFlagBits {
  // Provided by VK_VERSION_1_1
    VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT = 0x00000001,
} VkDeviceQueueCreateFlagBits;

VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT specifies that the device queue is a protected-capable queue.

// Provided by VK_VERSION_1_0
typedef VkFlags VkDeviceQueueCreateFlags;

VkDeviceQueueCreateFlags is a bitmask type for setting a mask of zero or more VkDeviceQueueCreateFlagBits.

A queue can be created with a system-wide priority by adding a VkDeviceQueueGlobalPriorityCreateInfoEXT structure to the pNext chain of VkDeviceQueueCreateInfo.

The VkDeviceQueueGlobalPriorityCreateInfoEXT structure is defined as:

// Provided by VK_EXT_global_priority
typedef struct VkDeviceQueueGlobalPriorityCreateInfoEXT {
    VkStructureType             sType;
    const void*                 pNext;
    VkQueueGlobalPriorityEXT    globalPriority;
} VkDeviceQueueGlobalPriorityCreateInfoEXT;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure.
globalPriority is the system-wide priority associated to this queue as specified by VkQueueGlobalPriorityEXT

A queue created without specifying VkDeviceQueueGlobalPriorityCreateInfoEXT will default to VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT.

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT
globalPriority must be a valid VkQueueGlobalPriorityEXT value

Possible values of VkDeviceQueueGlobalPriorityCreateInfoEXT::globalPriority, specifying a system-wide priority level are:

// Provided by VK_EXT_global_priority
typedef enum VkQueueGlobalPriorityEXT {
    VK_QUEUE_GLOBAL_PRIORITY_LOW_EXT = 128,
    VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT = 256,
    VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXT = 512,
    VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXT = 1024,
} VkQueueGlobalPriorityEXT;

Priority values are sorted in ascending order. A comparison operation on the enum values can be used to determine the priority order.

VK_QUEUE_GLOBAL_PRIORITY_LOW_EXT is below the system default. Useful for non-interactive tasks.
VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT is the system default priority.
VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXT is above the system default.
VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXT is the highest priority. Useful for critical tasks.

Queues with higher system priority may be allotted more processing time than queues with lower priority. An implementation may allow a higher-priority queue to starve a lower-priority queue until the higher-priority queue has no further commands to execute.

Priorities imply no ordering or scheduling constraints.

No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.

The global priority level of a queue takes precedence over the per-process queue priority (VkDeviceQueueCreateInfo::pQueuePriorities).

Abuse of this feature may result in starving the rest of the system of implementation resources. Therefore, the driver implementation may deny requests to acquire a priority above the default priority (VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT) if the caller does not have sufficient privileges. In this scenario VK_ERROR_NOT_PERMITTED_EXT is returned.

The driver implementation may fail the queue allocation request if resources required to complete the operation have been exhausted (either by the same process or a different process). In this scenario VK_ERROR_INITIALIZATION_FAILED is returned.

To retrieve a handle to a VkQueue object, call:

// Provided by VK_VERSION_1_0
void vkGetDeviceQueue(
    VkDevice                                    device,
    uint32_t                                    queueFamilyIndex,
    uint32_t                                    queueIndex,
    VkQueue*                                    pQueue);

device is the logical device that owns the queue.
queueFamilyIndex is the index of the queue family to which the queue belongs.
queueIndex is the index within this queue family of the queue to retrieve.
pQueue is a pointer to a VkQueue object that will be filled with the handle for the requested queue.

vkGetDeviceQueue must only be used to get queues that were created with the flags parameter of VkDeviceQueueCreateInfo set to zero. To get queues that were created with a non-zero flags parameter use vkGetDeviceQueue2.

Valid Usage

queueFamilyIndex must be one of the queue family indices specified when device was created, via the VkDeviceQueueCreateInfo structure
queueIndex must be less than the number of queues created for the specified queue family index when device was created, via the queueCount member of the VkDeviceQueueCreateInfo structure
VkDeviceQueueCreateInfo::flags must have been set to zero when device was created

Valid Usage (Implicit)

device must be a valid VkDevice handle
pQueue must be a valid pointer to a VkQueue handle

To retrieve a handle to a VkQueue object with specific VkDeviceQueueCreateFlags creation flags, call:

// Provided by VK_VERSION_1_1
void vkGetDeviceQueue2(
    VkDevice                                    device,
    const VkDeviceQueueInfo2*                   pQueueInfo,
    VkQueue*                                    pQueue);

device is the logical device that owns the queue.
pQueueInfo is a pointer to a VkDeviceQueueInfo2 structure, describing the parameters used to create the device queue.
pQueue is a pointer to a VkQueue object that will be filled with the handle for the requested queue.

Valid Usage (Implicit)

device must be a valid VkDevice handle
pQueueInfo must be a valid pointer to a valid VkDeviceQueueInfo2 structure
pQueue must be a valid pointer to a VkQueue handle

The VkDeviceQueueInfo2 structure is defined as:

// Provided by VK_VERSION_1_1
typedef struct VkDeviceQueueInfo2 {
    VkStructureType             sType;
    const void*                 pNext;
    VkDeviceQueueCreateFlags    flags;
    uint32_t                    queueFamilyIndex;
    uint32_t                    queueIndex;
} VkDeviceQueueInfo2;

sType is the type of this structure.
pNext is NULL or a pointer to a structure extending this structure. The pNext chain of VkDeviceQueueInfo2 is used to provide additional image parameters to vkGetDeviceQueue2.
flags is a VkDeviceQueueCreateFlags value indicating the flags used to create the device queue.
queueFamilyIndex is the index of the queue family to which the queue belongs.
queueIndex is the index within this queue family of the queue to retrieve.

The queue returned by vkGetDeviceQueue2 must have the same flags value from this structure as that used at device creation time in a VkDeviceQueueCreateInfo instance. If no matching flags were specified at device creation time then pQueue will return VK_NULL_HANDLE.

Valid Usage

queueFamilyIndex must be one of the queue family indices specified when device was created, via the VkDeviceQueueCreateInfo structure
queueIndex must be less than the number of queues created for the specified queue family index and VkDeviceQueueCreateFlags member flags equal to this flags value when device was created, via the queueCount member of the VkDeviceQueueCreateInfo structure

Valid Usage (Implicit)

sType must be VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2
pNext must be NULL
flags must be a valid combination of VkDeviceQueueCreateFlagBits values

4.3.3. Queue Family Index

The queue family index is used in multiple places in Vulkan in order to tie operations to a specific family of queues.

When retrieving a handle to the queue via vkGetDeviceQueue, the queue family index is used to select which queue family to retrieve the VkQueue handle from as described in the previous section.

When creating a VkCommandPool object (see Command Pools), a queue family index is specified in the VkCommandPoolCreateInfo structure. Command buffers from this pool can only be submitted on queues corresponding to this queue family.

When creating VkImage (see Images) and VkBuffer (see Buffers) resources, a set of queue families is included in the VkImageCreateInfo and VkBufferCreateInfo structures to specify the queue families that can access the resource.

When inserting a VkBufferMemoryBarrier or VkImageMemoryBarrier (see Pipeline Barriers), a source and destination queue family index is specified to allow the ownership of a buffer or image to be transferred from one queue family to another. See the Resource Sharing section for details.

4.3.4. Queue Priority

Each queue is assigned a priority, as set in the VkDeviceQueueCreateInfo structures when creating the device. The priority of each queue is a normalized floating point value between 0.0 and 1.0, which is then translated to a discrete priority level by the implementation. Higher values indicate a higher priority, with 0.0 being the lowest priority and 1.0 being the highest.

Within the same device, queues with higher priority may be allotted more processing time than queues with lower priority. The implementation makes no guarantees with regards to ordering or scheduling among queues with the same priority, other than the constraints defined by any explicit synchronization primitives. The implementation make no guarantees with regards to queues across different devices.

An implementation may allow a higher-priority queue to starve a lower-priority queue on the same VkDevice until the higher-priority queue has no further commands to execute. The relationship of queue priorities must not cause queues on one VkDevice to starve queues on another VkDevice.

No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.

4.3.5. Queue Submission

Work is submitted to a queue via queue submission commands such as vkQueueSubmit. Queue submission commands define a set of queue operations to be executed by the underlying physical device, including synchronization with semaphores and fences.

Submission commands take as parameters a target queue, zero or more batches of work, and an optional fence to signal upon completion. Each batch consists of three distinct parts:

Zero or more semaphores to wait on before execution of the rest of the batch.
- If present, these describe a semaphore wait operation.
Zero or more work items to execute.
- If present, these describe a queue operation matching the work described.
Zero or more semaphores to signal upon completion of the work items.
- If present, these describe a semaphore signal operation.

If a fence is present in a queue submission, it describes a fence signal operation.

All work described by a queue submission command must be submitted to the queue before the command returns.

Sparse Memory Binding

In Vulkan it is possible to sparsely bind memory to buffers and images as described in the Sparse Resource chapter. Sparse memory binding is a queue operation. A queue whose flags include the VK_QUEUE_SPARSE_BINDING_BIT must be able to support the mapping of a virtual address to a physical address on the device. This causes an update to the page table mappings on the device. This update must be synchronized on a queue to avoid corrupting page table mappings during execution of graphics commands. By binding the sparse memory resources on queues, all commands that are dependent on the updated bindings are synchronized to only execute after the binding is updated. See the Synchronization and Cache Control chapter for how this synchronization is accomplished.

4.3.6. Queue Destruction

Queues are created along with a logical device during vkCreateDevice. All queues associated with a logical device are destroyed when vkDestroyDevice is called on that device.