// Copyright 2015-2023 The Khronos Group Inc. // // SPDX-License-Identifier: CC-BY-4.0 [[queries]] = Queries _Queries_ provide a mechanism to return information about the processing of a sequence of Vulkan commands. Query operations are asynchronous, and as such, their results are not returned immediately. Instead, their results, and their availability status are stored in a <>. The state of these queries can: be read back on the host, or copied to a buffer object on the device. The supported query types are <>, <>, ifdef::VK_KHR_video_queue[] <>, endif::VK_KHR_video_queue[] ifdef::VK_KHR_video_encode_queue[] <> endif::VK_KHR_video_encode_queue[] and <>. ifdef::VK_KHR_performance_query[] <> are supported if the associated extension is available. endif::VK_KHR_performance_query[] ifdef::VK_EXT_transform_feedback[] <> are supported if the associated extension is available. endif::VK_EXT_transform_feedback[] ifdef::VK_INTEL_performance_query[] <> are supported if the associated extension is available. endif::VK_INTEL_performance_query[] ifdef::VK_EXT_mesh_shader[] <> are supported if the associated extension is available. endif::VK_EXT_mesh_shader[] ifdef::VK_KHR_acceleration_structure,VK_NV_ray_tracing[] Several additional queries with specific purposes associated with ray tracing are available if the corresponding extensions are supported, as described for elink:VkQueryType. endif::VK_KHR_acceleration_structure,VK_NV_ray_tracing[] [[queries-pools]] == Query Pools [open,refpage='VkQueryPool',desc='Opaque handle to a query pool object',type='handles'] -- Queries are managed using _query pool_ objects. Each query pool is a collection of a specific number of queries of a particular type. Query pools are represented by sname:VkQueryPool handles: include::{generated}/api/handles/VkQueryPool.adoc[] -- [open,refpage='vkCreateQueryPool',desc='Create a new query pool object',type='protos'] -- :refpage: vkCreateQueryPool :objectnameplural: query pools :objectnamecamelcase: queryPool :objectcount: 1 To create a query pool, call: include::{generated}/api/protos/vkCreateQueryPool.adoc[] * pname:device is the logical device that creates the query pool. * pname:pCreateInfo is a pointer to a slink:VkQueryPoolCreateInfo structure containing the number and type of queries to be managed by the pool. * pname:pAllocator controls host memory allocation as described in the <> chapter. * pname:pQueryPool is a pointer to a slink:VkQueryPool handle in which the resulting query pool object is returned. include::{chapters}/commonvalidity/no_dynamic_allocations_common.adoc[] ifdef::VKSC_VERSION_1_0[] .Valid Usage **** include::{chapters}/commonvalidity/memory_reservation_request_count_common.adoc[] **** endif::VKSC_VERSION_1_0[] include::{generated}/validity/protos/vkCreateQueryPool.adoc[] -- [open,refpage='VkQueryPoolCreateInfo',desc='Structure specifying parameters of a newly created query pool',type='structs'] -- The sname:VkQueryPoolCreateInfo structure is defined as: include::{generated}/api/structs/VkQueryPoolCreateInfo.adoc[] * pname:sType is a elink:VkStructureType value identifying this structure. * pname:pNext is `NULL` or a pointer to a structure extending this structure. * pname:flags is reserved for future use. * pname:queryType is a elink:VkQueryType value specifying the type of queries managed by the pool. * pname:queryCount is the number of queries managed by the pool. * pname:pipelineStatistics is a bitmask of elink:VkQueryPipelineStatisticFlagBits specifying which counters will be returned in queries on the new pool, as described below in <>. pname:pipelineStatistics is ignored if pname:queryType is not ename:VK_QUERY_TYPE_PIPELINE_STATISTICS. .Valid Usage **** * [[VUID-VkQueryPoolCreateInfo-queryType-00791]] If the <> feature is not enabled, pname:queryType must: not be ename:VK_QUERY_TYPE_PIPELINE_STATISTICS ifdef::VK_EXT_mesh_shader[] * [[VUID-VkQueryPoolCreateInfo-meshShaderQueries-07068]] If the <> feature is not enabled, pname:queryType must: not be ename:VK_QUERY_TYPE_MESH_PRIMITIVES_GENERATED_EXT * [[VUID-VkQueryPoolCreateInfo-meshShaderQueries-07069]] If the <> feature is not enabled, and pname:queryType is ename:VK_QUERY_TYPE_PIPELINE_STATISTICS, pname:pipelineStatistics must: not contain ename:VK_QUERY_PIPELINE_STATISTIC_TASK_SHADER_INVOCATIONS_BIT_EXT or ename:VK_QUERY_PIPELINE_STATISTIC_MESH_SHADER_INVOCATIONS_BIT_EXT endif::VK_EXT_mesh_shader[] * [[VUID-VkQueryPoolCreateInfo-queryType-00792]] If pname:queryType is ename:VK_QUERY_TYPE_PIPELINE_STATISTICS, pname:pipelineStatistics must: be a valid combination of elink:VkQueryPipelineStatisticFlagBits values ifdef::VK_KHR_performance_query[] * [[VUID-VkQueryPoolCreateInfo-queryType-03222]] If pname:queryType is ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, the pname:pNext chain must: include a slink:VkQueryPoolPerformanceCreateInfoKHR structure endif::VK_KHR_performance_query[] * [[VUID-VkQueryPoolCreateInfo-queryCount-02763]] pname:queryCount must: be greater than 0 ifdef::VKSC_VERSION_1_0[] * [[VUID-VkQueryPoolCreateInfo-queryType-05046]] If pname:queryType is ename:VK_QUERY_TYPE_OCCLUSION then pname:queryCount must: be less than or equal to the maximum of all slink:VkDeviceObjectReservationCreateInfo::pname:maxOcclusionQueriesPerPool values specified when pname:device was created * [[VUID-VkQueryPoolCreateInfo-queryType-05047]] If pname:queryType is ename:VK_QUERY_TYPE_PIPELINE_STATISTICS then pname:queryCount must: be less than or equal to the maximum of all slink:VkDeviceObjectReservationCreateInfo::pname:maxPipelineStatisticsQueriesPerPool values specified when pname:device was created * [[VUID-VkQueryPoolCreateInfo-queryType-05048]] If pname:queryType is ename:VK_QUERY_TYPE_TIMESTAMP then pname:queryCount must: be less than or equal to the maximum of all slink:VkDeviceObjectReservationCreateInfo::pname:maxTimestampQueriesPerPool values specified when pname:device was created ifdef::VK_KHR_performance_query[] * [[VUID-VkQueryPoolCreateInfo-queryType-05049]] If pname:queryType is ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR then pname:queryCount must: be less than or equal to the maximum of all slink:VkPerformanceQueryReservationInfoKHR::pname:maxPerformanceQueriesPerPool values specified when pname:device was created endif::VK_KHR_performance_query[] endif::VKSC_VERSION_1_0[] ifdef::VK_KHR_video_encode_queue[] * [[VUID-VkQueryPoolCreateInfo-queryType-07133]] If pname:queryType is ename:VK_QUERY_TYPE_VIDEO_ENCODE_FEEDBACK_KHR, then the pname:pNext chain must: include a slink:VkVideoProfileInfoKHR structure with pname:videoCodecOperation specifying an encode operation * [[VUID-VkQueryPoolCreateInfo-queryType-07906]] If pname:queryType is ename:VK_QUERY_TYPE_VIDEO_ENCODE_FEEDBACK_KHR, then the pname:pNext chain must: include a slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR structure * [[VUID-VkQueryPoolCreateInfo-queryType-07907]] If pname:queryType is ename:VK_QUERY_TYPE_VIDEO_ENCODE_FEEDBACK_KHR, and the pname:pNext chain includes a slink:VkVideoProfileInfoKHR structure and a slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR structure, then slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR::pname:encodeFeedbackFlags must: not contain any bits that are not set in slink:VkVideoEncodeCapabilitiesKHR::pname:supportedEncodeFeedbackFlags, as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the <> described by slink:VkVideoProfileInfoKHR and its pname:pNext chain endif::VK_KHR_video_encode_queue[] **** include::{generated}/validity/structs/VkQueryPoolCreateInfo.adoc[] -- [open,refpage='VkQueryPoolCreateFlags',desc='Reserved for future use',type='flags'] -- include::{generated}/api/flags/VkQueryPoolCreateFlags.adoc[] tname:VkQueryPoolCreateFlags is a bitmask type for setting a mask, but is currently reserved for future use. -- ifdef::VK_KHR_performance_query[] include::{chapters}/VK_KHR_performance_query/querycreateinfo.adoc[] endif::VK_KHR_performance_query[] ifdef::VKSC_VERSION_1_0[] ifdef::hidden[] // tag::scremoved[] * fname:vkDestroyQueryPool <> // end::scremoved[] endif::hidden[] Query pools cannot: be destroyed <>. If slink:VkPhysicalDeviceVulkanSC10Properties::<> is ename:VK_TRUE, the memory is returned to the system when the device is destroyed. endif::VKSC_VERSION_1_0[] ifndef::VKSC_VERSION_1_0[] [open,refpage='vkDestroyQueryPool',desc='Destroy a query pool object',type='protos'] -- To destroy a query pool, call: include::{generated}/api/protos/vkDestroyQueryPool.adoc[] * pname:device is the logical device that destroys the query pool. * pname:queryPool is the query pool to destroy. * pname:pAllocator controls host memory allocation as described in the <> chapter. .Valid Usage **** * [[VUID-vkDestroyQueryPool-queryPool-00793]] All submitted commands that refer to pname:queryPool must: have completed execution * [[VUID-vkDestroyQueryPool-queryPool-00794]] If sname:VkAllocationCallbacks were provided when pname:queryPool was created, a compatible set of callbacks must: be provided here * [[VUID-vkDestroyQueryPool-queryPool-00795]] If no sname:VkAllocationCallbacks were provided when pname:queryPool was created, pname:pAllocator must: be `NULL` **** [NOTE] .Note ==== Applications can: verify that pname:queryPool can: be destroyed by checking that fname:vkGetQueryPoolResults() without the ename:VK_QUERY_RESULT_PARTIAL_BIT flag returns ename:VK_SUCCESS for all queries that are used in command buffers submitted for execution. ==== include::{generated}/validity/protos/vkDestroyQueryPool.adoc[] -- endif::VKSC_VERSION_1_0[] [open,refpage='VkQueryType',desc='Specify the type of queries managed by a query pool',type='enums'] -- Possible values of slink:VkQueryPoolCreateInfo::pname:queryType, specifying the type of queries managed by the pool, are: include::{generated}/api/enums/VkQueryType.adoc[] * ename:VK_QUERY_TYPE_OCCLUSION specifies an <>. * ename:VK_QUERY_TYPE_PIPELINE_STATISTICS specifies a <>. * ename:VK_QUERY_TYPE_TIMESTAMP specifies a <>. ifdef::VK_KHR_performance_query[] * ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR specifies a <>. endif::VK_KHR_performance_query[] ifdef::VK_EXT_transform_feedback[] * ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT specifies a <>. endif::VK_EXT_transform_feedback[] ifdef::VK_EXT_primitives_generated_query[] * ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT specifies a <>. endif::VK_EXT_primitives_generated_query[] ifdef::VK_KHR_acceleration_structure[] * ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR specifies a <> for use with flink:vkCmdWriteAccelerationStructuresPropertiesKHR or flink:vkWriteAccelerationStructuresPropertiesKHR. * ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR specifies a <>. endif::VK_KHR_acceleration_structure[] ifdef::VK_KHR_ray_tracing_maintenance1[] * ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SIZE_KHR specifies an <> for use with flink:vkCmdWriteAccelerationStructuresPropertiesKHR or flink:vkWriteAccelerationStructuresPropertiesKHR. * ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_BOTTOM_LEVEL_POINTERS_KHR specifies a <>. endif::VK_KHR_ray_tracing_maintenance1[] ifdef::VK_NV_ray_tracing[] * ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV specifies an <> for use with flink:vkCmdWriteAccelerationStructuresPropertiesNV. endif::VK_NV_ray_tracing[] ifdef::VK_INTEL_performance_query[] * ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL specifies a <>. endif::VK_INTEL_performance_query[] ifdef::VK_KHR_video_queue[] * ename:VK_QUERY_TYPE_RESULT_STATUS_ONLY_KHR specifies a <>. endif::VK_KHR_video_queue[] ifdef::VK_KHR_video_encode_queue[] * ename:VK_QUERY_TYPE_VIDEO_ENCODE_FEEDBACK_KHR specifies a <>. endif::VK_KHR_video_encode_queue[] ifdef::VK_EXT_mesh_shader[] * ename:VK_QUERY_TYPE_MESH_PRIMITIVES_GENERATED_EXT specifies a <>. endif::VK_EXT_mesh_shader[] -- [[queries-operation]] == Query Operation The operation of queries is controlled by the commands flink:vkCmdBeginQuery, flink:vkCmdEndQuery, ifdef::VK_EXT_transform_feedback[] flink:vkCmdBeginQueryIndexedEXT, flink:vkCmdEndQueryIndexedEXT, endif::VK_EXT_transform_feedback[] flink:vkCmdResetQueryPool, flink:vkCmdCopyQueryPoolResults, ifdef::VK_VERSION_1_3,VK_KHR_synchronization2[] flink:vkCmdWriteTimestamp2, endif::VK_VERSION_1_3,VK_KHR_synchronization2[] and flink:vkCmdWriteTimestamp. In order for a sname:VkCommandBuffer to record query management commands, the queue family for which its sname:VkCommandPool was created must: support the appropriate type of operations (graphics, compute) suitable for the query type of a given query pool. Each query in a query pool has a status that is either _unavailable_ or _available_, and also has state to store the numerical results of a query operation of the type requested when the query pool was created. Resetting a query via flink:vkCmdResetQueryPool ifdef::VK_VERSION_1_2,VK_EXT_host_query_reset[] or flink:vkResetQueryPool endif::VK_VERSION_1_2,VK_EXT_host_query_reset[] sets the status to unavailable and makes the numerical results undefined:. A query is made available by the operation of flink:vkCmdEndQuery, ifdef::VK_EXT_transform_feedback[] flink:vkCmdEndQueryIndexedEXT, endif::VK_EXT_transform_feedback[] ifdef::VK_VERSION_1_3,VK_KHR_synchronization2[] flink:vkCmdWriteTimestamp2, endif::VK_VERSION_1_3,VK_KHR_synchronization2[] or flink:vkCmdWriteTimestamp. Both the availability status and numerical results can: be retrieved by calling either flink:vkGetQueryPoolResults or flink:vkCmdCopyQueryPoolResults. After query pool creation, each query is in an uninitialized state and must: be reset before it is used. Queries must: also be reset between uses. ifdef::VK_VERSION_1_1,VK_KHR_device_group[] If a logical device includes multiple physical devices, then each command that writes a query must: execute on a single physical device, and any call to flink:vkCmdBeginQuery must: execute the corresponding flink:vkCmdEndQuery command on the same physical device. endif::VK_VERSION_1_1,VK_KHR_device_group[] [open,refpage='vkCmdResetQueryPool',desc='Reset queries in a query pool',type='protos'] -- To reset a range of queries in a query pool on a queue, call: include::{generated}/api/protos/vkCmdResetQueryPool.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the handle of the query pool managing the queries being reset. * pname:firstQuery is the initial query index to reset. * pname:queryCount is the number of queries to reset. When executed on a queue, this command sets the status of query indices [eq]#[pname:firstQuery, pname:firstQuery {plus} pname:queryCount - 1]# to unavailable. This command defines an execution dependency between other query commands that reference the same query. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:firstQuery and pname:queryCount that occur earlier in <>. The second <> includes all commands which reference the queries in pname:queryPool indicated by pname:firstQuery and pname:queryCount that occur later in <>. The operation of this command happens after the first scope and happens before the second scope. ifdef::VK_KHR_performance_query[] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, this command sets the status of query indices [eq]#[pname:firstQuery, pname:firstQuery {plus} pname:queryCount - 1]# to unavailable for each pass of pname:queryPool, as indicated by a call to flink:vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR. [NOTE] .Note ==== Because fname:vkCmdResetQueryPool resets all the passes of the indicated queries, applications must not record a fname:vkCmdResetQueryPool command for a pname:queryPool created with ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR in a command buffer that needs to be submitted multiple times as indicated by a call to flink:vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR. Otherwise applications will never be able to complete the recorded queries. ==== endif::VK_KHR_performance_query[] .Valid Usage **** * [[VUID-vkCmdResetQueryPool-firstQuery-00796]] pname:firstQuery must: be less than the number of queries in pname:queryPool * [[VUID-vkCmdResetQueryPool-firstQuery-00797]] The sum of pname:firstQuery and pname:queryCount must: be less than or equal to the number of queries in pname:queryPool * [[VUID-vkCmdResetQueryPool-None-02841]] All queries used by the command must: not be active ifdef::VK_KHR_performance_query[] * [[VUID-vkCmdResetQueryPool-firstQuery-02862]] If pname:queryPool was created with ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, this command must: not be recorded in a command buffer that, either directly or through secondary command buffers, also contains begin commands for a query from the set of queries [eq]#[pname:firstQuery, pname:firstQuery {plus} pname:queryCount - 1]# endif::VK_KHR_performance_query[] **** include::{generated}/validity/protos/vkCmdResetQueryPool.adoc[] -- ifdef::VK_VERSION_1_2,VK_EXT_host_query_reset[] [open,refpage='vkResetQueryPool',desc='Reset queries in a query pool',type='protos',alias='vkResetQueryPoolEXT'] -- To reset a range of queries in a query pool on the host, call: ifdef::VK_VERSION_1_2[] include::{generated}/api/protos/vkResetQueryPool.adoc[] endif::VK_VERSION_1_2[] ifdef::VK_VERSION_1_2+VK_EXT_host_query_reset[or the equivalent command] ifdef::VK_EXT_host_query_reset[] include::{generated}/api/protos/vkResetQueryPoolEXT.adoc[] endif::VK_EXT_host_query_reset[] * pname:device is the logical device that owns the query pool. * pname:queryPool is the handle of the query pool managing the queries being reset. * pname:firstQuery is the initial query index to reset. * pname:queryCount is the number of queries to reset. This command sets the status of query indices [eq]#[pname:firstQuery, pname:firstQuery {plus} pname:queryCount - 1]# to unavailable. ifdef::VK_KHR_performance_query[] If pname:queryPool is ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR this command sets the status of query indices [eq]#[pname:firstQuery, pname:firstQuery {plus} pname:queryCount - 1]# to unavailable for each pass. endif::VK_KHR_performance_query[] .Valid Usage **** * [[VUID-vkResetQueryPool-None-02665]] The <> feature must: be enabled * [[VUID-vkResetQueryPool-firstQuery-02666]] pname:firstQuery must: be less than the number of queries in pname:queryPool * [[VUID-vkResetQueryPool-firstQuery-02667]] The sum of pname:firstQuery and pname:queryCount must: be less than or equal to the number of queries in pname:queryPool * [[VUID-vkResetQueryPool-firstQuery-02741]] Submitted commands that refer to the range specified by pname:firstQuery and pname:queryCount in pname:queryPool must: have completed execution * [[VUID-vkResetQueryPool-firstQuery-02742]] The range of queries specified by pname:firstQuery and pname:queryCount in pname:queryPool must: not be in use by calls to flink:vkGetQueryPoolResults or fname:vkResetQueryPool in other threads **** include::{generated}/validity/protos/vkResetQueryPool.adoc[] -- endif::VK_VERSION_1_2,VK_EXT_host_query_reset[] Once queries are reset and ready for use, query commands can: be issued to a command buffer. Occlusion queries and pipeline statistics queries count events - drawn samples and pipeline stage invocations, respectively - resulting from commands that are recorded between a flink:vkCmdBeginQuery command and a flink:vkCmdEndQuery command within a specified command buffer, effectively scoping a set of drawing and/or dispatching commands. Timestamp queries write timestamps to a query pool. ifdef::VK_KHR_performance_query[] Performance queries record performance counters to a query pool. endif::VK_KHR_performance_query[] A query must: begin and end in the same command buffer, although if it is a primary command buffer, and the <> feature is enabled, it can: execute secondary command buffers during the query operation. For a secondary command buffer to be executed while a query is active, it must: set the pname:occlusionQueryEnable, pname:queryFlags, and/or pname:pipelineStatistics members of slink:VkCommandBufferInheritanceInfo to conservative values, as described in the <> section. A query must: either begin and end inside the same subpass of a render pass instance, or must: both begin and end outside of a render pass instance (i.e. contain entire render pass instances). ifdef::VK_VERSION_1_1,VK_KHR_multiview[] If queries are used while executing a render pass instance that has multiview enabled, the query uses [eq]#N# consecutive query indices in the query pool (starting at pname:query) where [eq]#N# is the number of bits set in the view mask in the subpass the query is used in. How the numerical results of the query are distributed among the queries is implementation-dependent. For example, some implementations may: write each view's results to a distinct query, while other implementations may: write the total result to the first query and write zero to the other queries. However, the sum of the results in all the queries must: accurately reflect the total result of the query summed over all views. Applications can: sum the results from all the queries to compute the total result. Queries used with multiview rendering must: not span subpasses, i.e. they must: begin and end in the same subpass. endif::VK_VERSION_1_1,VK_KHR_multiview[] ifdef::VK_KHR_video_queue[] A query must: either begin and end inside the same video coding scope, or must: both begin and end outside of a video coding scope and must: not contain entire video coding scopes. endif::VK_KHR_video_queue[] [open,refpage='vkCmdBeginQuery',desc='Begin a query',type='protos',xrefs='vkCmdEndQuery vkCmdBeginQueryIndexedEXT vkCmdEndQueryIndexedEXT'] -- :refpage: vkCmdBeginQuery To begin a query, call: include::{generated}/api/protos/vkCmdBeginQuery.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the query pool that will manage the results of the query. * pname:query is the query index within the query pool that will contain the results. * pname:flags is a bitmask of elink:VkQueryControlFlagBits specifying constraints on the types of queries that can: be performed. If the pname:queryType of the pool is ename:VK_QUERY_TYPE_OCCLUSION and pname:flags contains ename:VK_QUERY_CONTROL_PRECISE_BIT, an implementation must: return a result that matches the actual number of samples passed. This is described in more detail in <>. ifdef::VK_EXT_transform_feedback[] Calling fname:vkCmdBeginQuery is equivalent to calling flink:vkCmdBeginQueryIndexedEXT with the pname:index parameter set to zero. endif::VK_EXT_transform_feedback[] [[queries-operation-active]] After beginning a query, that query is considered _active_ within the command buffer it was called in until that same query is ended. Queries active in a primary command buffer when secondary command buffers are executed are considered active for those secondary command buffers. ifdef::VK_KHR_video_queue[] Furthermore, if the query is started within a video coding scope, the following command buffer states are initialized for the query type: * [[queries-operation-active-query-index]] The _active_query_index_ is set to the value specified by pname:query. * [[queries-operation-last-activatable-query-index]] The _last activatable query index_ is also set to the value specified by pname:query. Each <> stores a result to the query corresponding to the current active query index, followed by incrementing the active query index. If the active query index gets incremented past the last activatable query index, issuing any further video coding operations results in undefined: behavior. [NOTE] .Note ==== In practice, this means that currently no more than a single video coding operation must: be issued between a begin and end query pair. ==== endif::VK_KHR_video_queue[] This command defines an execution dependency between other query commands that reference the same query. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur earlier in <>. The second <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur later in <>. The operation of this command happens after the first scope and happens before the second scope. .Valid Usage **** include::{chapters}/commonvalidity/query_begin_common.adoc[] * [[VUID-vkCmdBeginQuery-queryPool-01922]] pname:queryPool must: have been created with a pname:queryType that differs from that of any queries that are <> within pname:commandBuffer ifdef::VK_EXT_mesh_shader[] * [[VUID-vkCmdBeginQuery-queryType-07070]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_MESH_PRIMITIVES_GENERATED_EXT the sname:VkCommandPool that pname:commandBuffer was allocated from must: support graphics operations endif::VK_EXT_mesh_shader[] ifdef::VK_EXT_transform_feedback[] * [[VUID-vkCmdBeginQuery-queryType-02327]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT the sname:VkCommandPool that pname:commandBuffer was allocated from must: support graphics operations * [[VUID-vkCmdBeginQuery-queryType-02328]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT then sname:VkPhysicalDeviceTransformFeedbackPropertiesEXT::pname:transformFeedbackQueries must: be supported endif::VK_EXT_transform_feedback[] ifdef::VK_EXT_primitives_generated_query[] * [[VUID-vkCmdBeginQuery-queryType-06687]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT the sname:VkCommandPool that pname:commandBuffer was allocated from must: support graphics operations * [[VUID-vkCmdBeginQuery-queryType-06688]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT then <> must: be enabled endif::VK_EXT_primitives_generated_query[] include::{chapters}/commonvalidity/performance_query_begin_common.adoc[] **** include::{generated}/validity/protos/vkCmdBeginQuery.adoc[] -- ifdef::VK_EXT_transform_feedback[] [open,refpage='vkCmdBeginQueryIndexedEXT',desc='Begin an indexed query',type='protos',xrefs='vkCmdBeginQuery vkCmdEndQuery vkCmdEndQueryIndexedEXT'] -- :refpage: vkCmdBeginQueryIndexedEXT To begin an indexed query, call: include::{generated}/api/protos/vkCmdBeginQueryIndexedEXT.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the query pool that will manage the results of the query. * pname:query is the query index within the query pool that will contain the results. * pname:flags is a bitmask of elink:VkQueryControlFlagBits specifying constraints on the types of queries that can: be performed. * pname:index is the query type specific index. When the query type is ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT ifdef::VK_EXT_primitives_generated_query[] or ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT, endif::VK_EXT_primitives_generated_query[] the index represents the vertex stream. The fname:vkCmdBeginQueryIndexedEXT command operates the same as the flink:vkCmdBeginQuery command, except that it also accepts a query type specific pname:index parameter. This command defines an execution dependency between other query commands that reference the same query index. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:query and pname:index that occur earlier in <>. The second <> includes all commands which reference the queries in pname:queryPool indicated by pname:query and pname:index that occur later in <>. The operation of this command happens after the first scope and happens before the second scope. .Valid Usage **** include::{chapters}/commonvalidity/query_begin_common.adoc[] * [[VUID-vkCmdBeginQueryIndexedEXT-queryPool-04753]] If the pname:queryPool was created with the same pname:queryType as that of another <> query within pname:commandBuffer, then pname:index must: not match the index used for the active query * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-02338]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT the sname:VkCommandPool that pname:commandBuffer was allocated from must: support graphics operations * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-02339]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT the pname:index parameter must: be less than sname:VkPhysicalDeviceTransformFeedbackPropertiesEXT::pname:maxTransformFeedbackStreams * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-06692]] If the pname:queryType used to create pname:queryPool was not ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT ifdef::VK_EXT_primitives_generated_query[] and not ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT, endif::VK_EXT_primitives_generated_query[] the pname:index must: be zero ifdef::VK_EXT_primitives_generated_query[] * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-06689]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT the sname:VkCommandPool that pname:commandBuffer was allocated from must: support graphics operations * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-06690]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT the pname:index parameter must: be less than sname:VkPhysicalDeviceTransformFeedbackPropertiesEXT::pname:maxTransformFeedbackStreams * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-06691]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT and the <> feature is not enabled, the pname:index parameter must: be zero * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-06693]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT then <> must: be enabled endif::VK_EXT_primitives_generated_query[] * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-02341]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT then sname:VkPhysicalDeviceTransformFeedbackPropertiesEXT::pname:transformFeedbackQueries must: be supported ifdef::VK_EXT_mesh_shader[] * [[VUID-vkCmdBeginQueryIndexedEXT-queryType-07071]] The pname:queryType used to create pname:queryPool must: not be ename:VK_QUERY_TYPE_MESH_PRIMITIVES_GENERATED_EXT endif::VK_EXT_mesh_shader[] include::{chapters}/commonvalidity/performance_query_begin_common.adoc[] **** include::{generated}/validity/protos/vkCmdBeginQueryIndexedEXT.adoc[] -- endif::VK_EXT_transform_feedback[] [open,refpage='VkQueryControlFlagBits',desc='Bitmask specifying constraints on a query',type='enums'] -- Bits which can: be set in flink:vkCmdBeginQuery::pname:flags, specifying constraints on the types of queries that can: be performed, are: include::{generated}/api/enums/VkQueryControlFlagBits.adoc[] * ename:VK_QUERY_CONTROL_PRECISE_BIT specifies the precision of <>. -- [open,refpage='VkQueryControlFlags',desc='Bitmask of VkQueryControlFlagBits',type='flags'] -- include::{generated}/api/flags/VkQueryControlFlags.adoc[] tname:VkQueryControlFlags is a bitmask type for setting a mask of zero or more elink:VkQueryControlFlagBits. -- [open,refpage='vkCmdEndQuery',desc='Ends a query',type='protos',xrefs='vkCmdBeginQuery vkCmdBeginQueryIndexedEXT vkCmdEndQueryIndexedEXT'] -- :refpage: vkCmdEndQuery To end a query after the set of desired drawing or dispatching commands is executed, call: include::{generated}/api/protos/vkCmdEndQuery.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the query pool that is managing the results of the query. * pname:query is the query index within the query pool where the result is stored. The command completes the query in pname:queryPool identified by pname:query, and marks it as available. This command defines an execution dependency between other query commands that reference the same query. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur earlier in <>. The second <> includes only the operation of this command. ifdef::VK_EXT_transform_feedback[] Calling fname:vkCmdEndQuery is equivalent to calling flink:vkCmdEndQueryIndexedEXT with the pname:index parameter set to zero. endif::VK_EXT_transform_feedback[] .Valid Usage **** * [[VUID-vkCmdEndQuery-None-01923]] All queries used by the command must: be <> * [[VUID-vkCmdEndQuery-query-00810]] pname:query must: be less than the number of queries in pname:queryPool ifdef::VK_VERSION_1_1[] * [[VUID-vkCmdEndQuery-commandBuffer-01886]] pname:commandBuffer must: not be a protected command buffer endif::VK_VERSION_1_1[] ifdef::VK_VERSION_1_1,VK_KHR_multiview[] * [[VUID-vkCmdEndQuery-query-00812]] If fname:vkCmdEndQuery is called within a render pass instance, the sum of pname:query and the number of bits set in the current subpass's view mask must: be less than or equal to the number of queries in pname:queryPool endif::VK_VERSION_1_1,VK_KHR_multiview[] ifdef::VK_KHR_performance_query[] * [[VUID-vkCmdEndQuery-queryPool-03227]] If pname:queryPool was created with a pname:queryType of ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR and one or more of the counters used to create pname:queryPool was ename:VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR, the flink:vkCmdEndQuery must: be the last recorded command in pname:commandBuffer * [[VUID-vkCmdEndQuery-queryPool-03228]] If pname:queryPool was created with a pname:queryType of ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR and one or more of the counters used to create pname:queryPool was ename:VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR, the flink:vkCmdEndQuery must: not be recorded within a render pass instance endif::VK_KHR_performance_query[] include::{chapters}/commonvalidity/query_end_common.adoc[] **** include::{generated}/validity/protos/vkCmdEndQuery.adoc[] -- ifdef::VK_EXT_transform_feedback[] [open,refpage='vkCmdEndQueryIndexedEXT',desc='Ends a query',type='protos',xrefs='vkCmdBeginQuery vkCmdEndQuery vkCmdBeginQueryIndexedEXT'] -- :refpage: vkCmdEndQueryIndexedEXT To end an indexed query after the set of desired drawing or dispatching commands is recorded, call: include::{generated}/api/protos/vkCmdEndQueryIndexedEXT.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the query pool that is managing the results of the query. * pname:query is the query index within the query pool where the result is stored. * pname:index is the query type specific index. The command completes the query in pname:queryPool identified by pname:query and pname:index, and marks it as available. The fname:vkCmdEndQueryIndexedEXT command operates the same as the flink:vkCmdEndQuery command, except that it also accepts a query type specific pname:index parameter. This command defines an execution dependency between other query commands that reference the same query index. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur earlier in <>. The second <> includes only the operation of this command. .Valid Usage **** * [[VUID-vkCmdEndQueryIndexedEXT-None-02342]] All queries used by the command must: be <> * [[VUID-vkCmdEndQueryIndexedEXT-query-02343]] pname:query must: be less than the number of queries in pname:queryPool ifdef::VK_VERSION_1_1[] * [[VUID-vkCmdEndQueryIndexedEXT-commandBuffer-02344]] pname:commandBuffer must: not be a protected command buffer endif::VK_VERSION_1_1[] ifdef::VK_VERSION_1_1,VK_KHR_multiview[] * [[VUID-vkCmdEndQueryIndexedEXT-query-02345]] If fname:vkCmdEndQueryIndexedEXT is called within a render pass instance, the sum of pname:query and the number of bits set in the current subpass's view mask must: be less than or equal to the number of queries in pname:queryPool endif::VK_VERSION_1_1,VK_KHR_multiview[] * [[VUID-vkCmdEndQueryIndexedEXT-queryType-06694]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT ifdef::VK_EXT_primitives_generated_query[] or ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT, endif::VK_EXT_primitives_generated_query[] the pname:index parameter must: be less than sname:VkPhysicalDeviceTransformFeedbackPropertiesEXT::pname:maxTransformFeedbackStreams * [[VUID-vkCmdEndQueryIndexedEXT-queryType-06695]] If the pname:queryType used to create pname:queryPool was not ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT ifdef::VK_EXT_primitives_generated_query[] and not ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT, endif::VK_EXT_primitives_generated_query[] the pname:index must: be zero * [[VUID-vkCmdEndQueryIndexedEXT-queryType-06696]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT ifdef::VK_EXT_primitives_generated_query[] or ename:VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT, endif::VK_EXT_primitives_generated_query[] pname:index must: equal the pname:index used to begin the query include::{chapters}/commonvalidity/query_end_common.adoc[] **** include::{generated}/validity/protos/vkCmdEndQueryIndexedEXT.adoc[] -- endif::VK_EXT_transform_feedback[] [[queries-operation-memorylayout]] An application can: retrieve results either by requesting they be written into application-provided memory, or by requesting they be copied into a sname:VkBuffer. In either case, the layout in memory is defined as follows: * The first query's result is written starting at the first byte requested by the command, and each subsequent query's result begins pname:stride bytes later. * Occlusion queries, pipeline statistics queries, ifdef::VK_EXT_transform_feedback[] transform feedback queries, endif::VK_EXT_transform_feedback[] ifdef::VK_EXT_primitives_generated_query[] primitives generated queries, endif::VK_EXT_primitives_generated_query[] ifdef::VK_EXT_mesh_shader[] mesh shader queries, endif::VK_EXT_mesh_shader[] ifdef::VK_KHR_video_encode_queue[] video encode feedback queries, endif::VK_KHR_video_encode_queue[] and timestamp queries store results in a tightly packed array of unsigned integers, either 32- or 64-bits as requested by the command, storing the numerical results and, if requested, the availability status. ifdef::VK_KHR_performance_query[] * Performance queries store results in a tightly packed array whose type is determined by the pname:unit member of the corresponding slink:VkPerformanceCounterKHR. endif::VK_KHR_performance_query[] * If ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is used, the final element of each query's result is an integer indicating whether the query's result is available, with any non-zero value indicating that it is available. ifdef::VK_KHR_video_queue[] * If ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR is used, the final element of each query's result is an integer value indicating that status of the query result. Positive values indicate success, negative values indicate failure, and 0 indicates that the result is not yet available. Specific error codes are encoded in the elink:VkQueryResultStatusKHR enumeration. endif::VK_KHR_video_queue[] * Occlusion queries write one integer value - the number of samples passed. Pipeline statistics queries write one integer value for each bit that is enabled in the pname:pipelineStatistics when the pool is created, and the statistics values are written in bit order starting from the least significant bit. Timestamp queries write one integer value. ifdef::VK_KHR_performance_query[] Performance queries write one slink:VkPerformanceCounterResultKHR value for each slink:VkPerformanceCounterKHR in the query. endif::VK_KHR_performance_query[] ifdef::VK_EXT_transform_feedback[] Transform feedback queries write two integers; the first integer is the number of primitives successfully written to the corresponding transform feedback buffer and the second is the number of primitives output to the vertex stream, regardless of whether they were successfully captured or not. In other words, if the transform feedback buffer was sized too small for the number of primitives output by the vertex stream, the first integer represents the number of primitives actually written and the second is the number that would have been written if all the transform feedback buffers associated with that vertex stream were large enough. endif::VK_EXT_transform_feedback[] ifdef::VK_EXT_primitives_generated_query[] Primitives generated queries write the number of primitives output to the vertex stream, regardless of whether transform feedback is active or not, or whether they were successfully captured by transform feedback or not. This is identical to the second integer of the transform feedback queries if transform feedback is active. endif::VK_EXT_primitives_generated_query[] ifdef::VK_EXT_mesh_shader[] Mesh shader queries write a single integer. endif::VK_EXT_mesh_shader[] ifdef::VK_KHR_video_encode_queue[] Video encode feedback queries write one or more integer values for each bit that is enabled in slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR::pname:encodeFeedbackFlags when the pool is created, and the feedback values are written in bit order starting from the least significant bit, as described <>. endif::VK_KHR_video_encode_queue[] * If more than one query is retrieved and pname:stride is not at least as large as the size of the array of values corresponding to a single query, the values written to memory are undefined:. [open,refpage='vkGetQueryPoolResults',desc='Copy results of queries in a query pool to a host memory region',type='protos'] -- :refpage: vkGetQueryPoolResults To retrieve status and results for a set of queries, call: include::{generated}/api/protos/vkGetQueryPoolResults.adoc[] * pname:device is the logical device that owns the query pool. * pname:queryPool is the query pool managing the queries containing the desired results. * pname:firstQuery is the initial query index. * pname:queryCount is the number of queries to read. * pname:dataSize is the size in bytes of the buffer pointed to by pname:pData. * pname:pData is a pointer to a user-allocated buffer where the results will be written * pname:stride is the stride in bytes between results for individual queries within pname:pData. * pname:flags is a bitmask of elink:VkQueryResultFlagBits specifying how and when results are returned. Any results written for a query are written according to <>. If no bits are set in pname:flags, and all requested queries are in the available state, results are written as an array of 32-bit unsigned integer values. Behavior when not all queries are available is described <>. If ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, results for all queries in pname:queryPool identified by pname:firstQuery and pname:queryCount are copied to pname:pData, along with an extra availability ifdef::VK_KHR_video_queue[or status] value written directly after the results of each query and interpreted as an unsigned integer. A value of zero indicates that the results are not yet available, otherwise the query is complete and results are available. The size of the availability ifdef::VK_KHR_video_queue[or status] values is 64 bits if ename:VK_QUERY_RESULT_64_BIT is set in pname:flags. Otherwise, it is 32 bits. ifdef::VK_KHR_video_queue[] If ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR is set, results for all queries in pname:queryPool identified by pname:firstQuery and pname:queryCount are copied to pname:pData, along with an extra status value written directly after the results of each query and interpreted as a signed integer. A value of zero indicates that the results are not yet available. Positive values indicate that the operations within the query completed successfully, and the query results are valid. Negative values indicate that the operations within the query completed unsuccessfully. elink:VkQueryResultStatusKHR defines specific meaning for values returned here, though implementations are free to return other values. endif::VK_KHR_video_queue[] [NOTE] .Note ==== If ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT ifdef::VK_KHR_video_queue[or ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR] is set, the layout of data in the buffer is a __(result,availability)__ ifdef::VK_KHR_video_queue[or __(result,status)__] pair for each query returned, and pname:stride is the stride between each pair. ==== Results for any available query written by this command are final and represent the final result of the query. If ename:VK_QUERY_RESULT_PARTIAL_BIT is set, then for any query that is unavailable, an intermediate result between zero and the final result value is written for that query. Otherwise, any result written by this command is undefined:. If ename:VK_QUERY_RESULT_64_BIT is set, results and, if returned, availability ifdef::VK_KHR_video_queue[or status] values for all queries are written as an array of 64-bit values. ifdef::VK_KHR_performance_query[] If the pname:queryPool was created with ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, results for each query are written as an array of the type indicated by slink:VkPerformanceCounterKHR::pname:storage for the counter being queried. endif::VK_KHR_performance_query[] Otherwise, results and availability ifdef::VK_KHR_video_queue[or status] values are written as an array of 32-bit values. If an unsigned integer query's value overflows the result type, the value may: either wrap or saturate. ifdef::VK_KHR_performance_query[] If a signed integer query's value overflows the result type, the value is undefined:. If a floating point query's value is not representable as the result type, the value is undefined:. endif::VK_KHR_performance_query[] If ename:VK_QUERY_RESULT_WAIT_BIT is set, this command defines an execution dependency with any earlier commands that writes one of the identified queries. The first <> includes all instances of flink:vkCmdEndQuery, ifdef::VK_EXT_transform_feedback[] flink:vkCmdEndQueryIndexedEXT, endif::VK_EXT_transform_feedback[] ifdef::VK_VERSION_1_3,VK_KHR_synchronization2[] flink:vkCmdWriteTimestamp2, endif::VK_VERSION_1_3,VK_KHR_synchronization2[] and flink:vkCmdWriteTimestamp that reference any query in pname:queryPool indicated by pname:firstQuery and pname:queryCount. The second <> includes the host operations of this command. [[queries-wait-bit-not-set]] If ename:VK_QUERY_RESULT_WAIT_BIT is not set, fname:vkGetQueryPoolResults may: return ename:VK_NOT_READY if there are queries in the unavailable state. [NOTE] .Note ==== Applications must: take care to ensure that use of the ename:VK_QUERY_RESULT_WAIT_BIT bit has the desired effect. For example, if a query has been used previously and a command buffer records the commands fname:vkCmdResetQueryPool, fname:vkCmdBeginQuery, and fname:vkCmdEndQuery for that query, then the query will remain in the available state until ifdef::VK_VERSION_1_2,VK_EXT_host_query_reset[] fname:vkResetQueryPool is called or endif::VK_VERSION_1_2,VK_EXT_host_query_reset[] the fname:vkCmdResetQueryPool command executes on a queue. Applications can: use fences or events to ensure that a query has already been reset before checking for its results or availability status. Otherwise, a stale value could be returned from a previous use of the query. The above also applies when ename:VK_QUERY_RESULT_WAIT_BIT is used in combination with ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT. In this case, the returned availability status may: reflect the result of a previous use of the query unless ifdef::VK_VERSION_1_2,VK_EXT_host_query_reset[] fname:vkResetQueryPool is called or endif::VK_VERSION_1_2,VK_EXT_host_query_reset[] the fname:vkCmdResetQueryPool command has been executed since the last use of the query. ifdef::VK_KHR_video_queue[] A similar situation can arise with the ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR flag. endif::VK_KHR_video_queue[] ==== [NOTE] .Note ==== Applications can: double-buffer query pool usage, with a pool per frame, and reset queries at the end of the frame in which they are read. ==== include::{chapters}/commonvalidity/no_dynamic_allocations_common.adoc[] .Valid Usage **** * [[VUID-vkGetQueryPoolResults-None-09401]] All queries used by the command must: not be uninitialized * [[VUID-vkGetQueryPoolResults-firstQuery-00813]] pname:firstQuery must: be less than the number of queries in pname:queryPool * [[VUID-vkGetQueryPoolResults-flags-02828]] If ename:VK_QUERY_RESULT_64_BIT is not set in pname:flags ifdef::VK_KHR_performance_query[] and the pname:queryType used to create pname:queryPool was not ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, endif::VK_KHR_performance_query[] then pname:pData and pname:stride must: be multiples of `4` * [[VUID-vkGetQueryPoolResults-flags-00815]] If ename:VK_QUERY_RESULT_64_BIT is set in pname:flags then pname:pData and pname:stride must: be multiples of `8` * [[VUID-vkGetQueryPoolResults-stride-08993]] If ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, pname:stride must: be large enough to contain the unsigned integer representing availability ifdef::VK_KHR_video_queue[or status] in addition to the query result. ifdef::VK_KHR_performance_query[] * [[VUID-vkGetQueryPoolResults-queryType-03229]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, then pname:pData and pname:stride must: be multiples of the size of slink:VkPerformanceCounterResultKHR * [[VUID-vkGetQueryPoolResults-queryType-04519]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, then pname:stride must: be large enough to contain the slink:VkQueryPoolPerformanceCreateInfoKHR::pname:counterIndexCount used to create pname:queryPool times the size of slink:VkPerformanceCounterResultKHR endif::VK_KHR_performance_query[] * [[VUID-vkGetQueryPoolResults-firstQuery-00816]] The sum of pname:firstQuery and pname:queryCount must: be less than or equal to the number of queries in pname:queryPool * [[VUID-vkGetQueryPoolResults-dataSize-00817]] pname:dataSize must: be large enough to contain the result of each query, as described <> * [[VUID-vkGetQueryPoolResults-queryType-00818]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TIMESTAMP, pname:flags must: not contain ename:VK_QUERY_RESULT_PARTIAL_BIT ifdef::VK_KHR_performance_query[] * [[VUID-vkGetQueryPoolResults-queryType-03230]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, pname:flags must: not contain ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT, ifdef::VK_KHR_video_queue[] ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR, endif::VK_KHR_video_queue[] ename:VK_QUERY_RESULT_PARTIAL_BIT, or ename:VK_QUERY_RESULT_64_BIT * [[VUID-vkGetQueryPoolResults-queryType-03231]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, the pname:queryPool must: have been recorded once for each pass as retrieved via a call to flink:vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR endif::VK_KHR_performance_query[] ifdef::VK_KHR_video_queue[] * [[VUID-vkGetQueryPoolResults-queryType-04810]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_RESULT_STATUS_ONLY_KHR, then pname:flags must: include ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR * [[VUID-vkGetQueryPoolResults-flags-04811]] If pname:flags includes ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR, then it must: not include ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT endif::VK_KHR_video_queue[] **** include::{generated}/validity/protos/vkGetQueryPoolResults.adoc[] -- [open,refpage='VkQueryResultFlagBits',desc='Bitmask specifying how and when query results are returned',type='enums'] -- Bits which can: be set in flink:vkGetQueryPoolResults::pname:flags and flink:vkCmdCopyQueryPoolResults::pname:flags, specifying how and when results are returned, are: include::{generated}/api/enums/VkQueryResultFlagBits.adoc[] * ename:VK_QUERY_RESULT_64_BIT specifies the results will be written as an array of 64-bit unsigned integer values. If this bit is not set, the results will be written as an array of 32-bit unsigned integer values. * ename:VK_QUERY_RESULT_WAIT_BIT specifies that Vulkan will wait for each query's status to become available before retrieving its results. * ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT specifies that the availability status accompanies the results. * ename:VK_QUERY_RESULT_PARTIAL_BIT specifies that returning partial results is acceptable. ifdef::VK_KHR_video_queue[] * ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR specifies that the last value returned in the query is a elink:VkQueryResultStatusKHR value. See <> for information on how an application can determine whether the use of this flag bit is supported. endif::VK_KHR_video_queue[] -- [open,refpage='VkQueryResultFlags',desc='Bitmask of VkQueryResultFlagBits',type='flags'] -- include::{generated}/api/flags/VkQueryResultFlags.adoc[] tname:VkQueryResultFlags is a bitmask type for setting a mask of zero or more elink:VkQueryResultFlagBits. -- ifdef::VK_KHR_video_queue[] [open,refpage='VkQueryResultStatusKHR',desc='Specific status codes for operations',type='enums'] -- [[query-result-status-codes]] Specific status codes that can: be returned from a query are: include::{generated}/api/enums/VkQueryResultStatusKHR.adoc[] * ename:VK_QUERY_RESULT_STATUS_NOT_READY_KHR specifies that the query result is not yet available. * ename:VK_QUERY_RESULT_STATUS_ERROR_KHR specifies that operations did not complete successfully. * ename:VK_QUERY_RESULT_STATUS_COMPLETE_KHR specifies that operations completed successfully and the query result is available. ifdef::VK_KHR_video_encode_queue[] * ename:VK_QUERY_RESULT_STATUS_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_KHR indicates that a video encode operation did not complete successfully due to the destination video bitstream buffer range not being sufficiently large to fit the encoded bitstream data. endif::VK_KHR_video_encode_queue[] -- endif::VK_KHR_video_queue[] [open,refpage='vkCmdCopyQueryPoolResults',desc='Copy the results of queries in a query pool to a buffer object',type='protos'] -- To copy query statuses and numerical results directly to buffer memory, call: include::{generated}/api/protos/vkCmdCopyQueryPoolResults.adoc[] * pname:commandBuffer is the command buffer into which this command will be recorded. * pname:queryPool is the query pool managing the queries containing the desired results. * pname:firstQuery is the initial query index. * pname:queryCount is the number of queries. pname:firstQuery and pname:queryCount together define a range of queries. * pname:dstBuffer is a slink:VkBuffer object that will receive the results of the copy command. * pname:dstOffset is an offset into pname:dstBuffer. * pname:stride is the stride in bytes between results for individual queries within pname:dstBuffer. The required size of the backing memory for pname:dstBuffer is determined as described above for flink:vkGetQueryPoolResults. * pname:flags is a bitmask of elink:VkQueryResultFlagBits specifying how and when results are returned. Any results written for a query are written according to <>. Results for any query in pname:queryPool identified by pname:firstQuery and pname:queryCount that is available are copied to pname:dstBuffer. If ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, results for all queries in pname:queryPool identified by pname:firstQuery and pname:queryCount are copied to pname:dstBuffer, along with an extra availability value written directly after the results of each query and interpreted as an unsigned integer. A value of zero indicates that the results are not yet available, otherwise the query is complete and results are available. ifdef::VK_KHR_video_queue[] If ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR is set, results for all queries in pname:queryPool identified by pname:firstQuery and pname:queryCount are copied to pname:dstBuffer, along with an extra status value written directly after the results of each query and interpreted as a signed integer. A value of zero indicates that the results are not yet available. Positive values indicate that the operations within the query completed successfully, and the query results are valid. Negative values indicate that the operations within the query completed unsuccessfully. elink:VkQueryResultStatusKHR defines specific meaning for values returned here, though implementations are free to return other values. endif::VK_KHR_video_queue[] Results for any available query written by this command are final and represent the final result of the query. If ename:VK_QUERY_RESULT_PARTIAL_BIT is set, then for any query that is unavailable, an intermediate result between zero and the final result value is written for that query. Otherwise, any result written by this command is undefined:. If ename:VK_QUERY_RESULT_64_BIT is set, results and availability ifdef::VK_KHR_video_queue[or status] values for all queries are written as an array of 64-bit values. ifdef::VK_KHR_performance_query[] If the pname:queryPool was created with ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, results for each query are written as an array of the type indicated by slink:VkPerformanceCounterKHR::pname:storage for the counter being queried. endif::VK_KHR_performance_query[] Otherwise, results and availability ifdef::VK_KHR_video_queue[or status] values are written as an array of 32-bit values. If an unsigned integer query's value overflows the result type, the value may: either wrap or saturate. ifdef::VK_KHR_performance_query[] If a signed integer query's value overflows the result type, the value is undefined:. If a floating point query's value is not representable as the result type, the value is undefined:. endif::VK_KHR_performance_query[] This command defines an execution dependency between other query commands that reference the same query. The first <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur earlier in <>. If pname:flags does not include ename:VK_QUERY_RESULT_WAIT_BIT, ifdef::VK_EXT_transform_feedback[] flink:vkCmdEndQueryIndexedEXT, endif::VK_EXT_transform_feedback[] ifdef::VK_VERSION_1_3,VK_KHR_synchronization2[] flink:vkCmdWriteTimestamp2, endif::VK_VERSION_1_3,VK_KHR_synchronization2[] flink:vkCmdEndQuery, and flink:vkCmdWriteTimestamp are excluded from this scope. The second <> includes all commands which reference the queries in pname:queryPool indicated by pname:query that occur later in <>. The operation of this command happens after the first scope and happens before the second scope. fname:vkCmdCopyQueryPoolResults is considered to be a transfer operation, and its writes to buffer memory must: be synchronized using ename:VK_PIPELINE_STAGE_TRANSFER_BIT and ename:VK_ACCESS_TRANSFER_WRITE_BIT before using the results. .Valid Usage **** * [[VUID-vkCmdCopyQueryPoolResults-None-09402]] All queries used by the command must: not be uninitialized when the command is executed * [[VUID-vkCmdCopyQueryPoolResults-dstOffset-00819]] pname:dstOffset must: be less than the size of pname:dstBuffer * [[VUID-vkCmdCopyQueryPoolResults-firstQuery-00820]] pname:firstQuery must: be less than the number of queries in pname:queryPool * [[VUID-vkCmdCopyQueryPoolResults-firstQuery-00821]] The sum of pname:firstQuery and pname:queryCount must: be less than or equal to the number of queries in pname:queryPool * [[VUID-vkCmdCopyQueryPoolResults-flags-00822]] If ename:VK_QUERY_RESULT_64_BIT is not set in pname:flags then pname:dstOffset and pname:stride must: be multiples of `4` * [[VUID-vkCmdCopyQueryPoolResults-flags-00823]] If ename:VK_QUERY_RESULT_64_BIT is set in pname:flags then pname:dstOffset and pname:stride must: be multiples of `8` * [[VUID-vkCmdCopyQueryPoolResults-dstBuffer-00824]] pname:dstBuffer must: have enough storage, from pname:dstOffset, to contain the result of each query, as described <> * [[VUID-vkCmdCopyQueryPoolResults-dstBuffer-00825]] pname:dstBuffer must: have been created with ename:VK_BUFFER_USAGE_TRANSFER_DST_BIT usage flag * [[VUID-vkCmdCopyQueryPoolResults-dstBuffer-00826]] If pname:dstBuffer is non-sparse then it must: be bound completely and contiguously to a single sname:VkDeviceMemory object * [[VUID-vkCmdCopyQueryPoolResults-queryType-00827]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_TIMESTAMP, pname:flags must: not contain ename:VK_QUERY_RESULT_PARTIAL_BIT ifdef::VK_KHR_performance_query[] * [[VUID-vkCmdCopyQueryPoolResults-queryType-03232]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, slink:VkPhysicalDevicePerformanceQueryPropertiesKHR::pname:allowCommandBufferQueryCopies must: be ename:VK_TRUE * [[VUID-vkCmdCopyQueryPoolResults-queryType-03233]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, pname:flags must: not contain ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT, ifdef::VK_KHR_video_queue[] ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR, endif::VK_KHR_video_queue[] ename:VK_QUERY_RESULT_PARTIAL_BIT, or ename:VK_QUERY_RESULT_64_BIT * [[VUID-vkCmdCopyQueryPoolResults-queryType-03234]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, the pname:queryPool must: have been submitted once for each pass as retrieved via a call to flink:vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR endif::VK_KHR_performance_query[] ifdef::VK_INTEL_performance_query[] * [[VUID-vkCmdCopyQueryPoolResults-queryType-02734]] flink:vkCmdCopyQueryPoolResults must: not be called if the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL endif::VK_INTEL_performance_query[] ifdef::VK_KHR_video_queue[] * [[VUID-vkCmdCopyQueryPoolResults-queryType-06901]] If the pname:queryType used to create pname:queryPool was ename:VK_QUERY_TYPE_RESULT_STATUS_ONLY_KHR, then pname:flags must: include ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR * [[VUID-vkCmdCopyQueryPoolResults-flags-06902]] If pname:flags includes ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR, then it must: not include ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT endif::VK_KHR_video_queue[] * [[VUID-vkCmdCopyQueryPoolResults-None-07429]] All queries used by the command must: not be active * [[VUID-vkCmdCopyQueryPoolResults-None-08752]] All queries used by the command must: have been made _available_ by prior executed commands **** include::{generated}/validity/protos/vkCmdCopyQueryPoolResults.adoc[] -- [[queries-operation-undefined]] Rendering operations such as clears, MSAA resolves, attachment load/store operations, and blits may: count towards the results of queries. This behavior is implementation-dependent and may: vary depending on the path used within an implementation. For example, some implementations have several types of clears, some of which may: include vertices and some not. [[queries-occlusion]] == Occlusion Queries Occlusion queries track the number of samples that pass the per-fragment tests for a set of drawing commands. As such, occlusion queries are only available on queue families supporting graphics operations. The application can: then use these results to inform future rendering decisions. An occlusion query is begun and ended by calling fname:vkCmdBeginQuery and fname:vkCmdEndQuery, respectively. When an occlusion query begins, the count of passing samples always starts at zero. For each drawing command, the count is incremented as described in <>. If pname:flags does not contain ename:VK_QUERY_CONTROL_PRECISE_BIT an implementation may: generate any non-zero result value for the query if the count of passing samples is non-zero. [NOTE] .Note ==== Not setting ename:VK_QUERY_CONTROL_PRECISE_BIT mode may: be more efficient on some implementations, and should: be used where it is sufficient to know a boolean result on whether any samples passed the per-fragment tests. In this case, some implementations may: only return zero or one, indifferent to the actual number of samples passing the per-fragment tests. Setting ename:VK_QUERY_CONTROL_PRECISE_BIT does not guarantee that different implementations return the same number of samples in an occlusion query. Some implementations may kill fragments in the <>, and these killed fragments do not contribute to the final result of the query. It is possible that some implementations generate a zero result value for the query, while others generate a non-zero value. ==== When an occlusion query finishes, the result for that query is marked as available. The application can: then either copy the result to a buffer (via fname:vkCmdCopyQueryPoolResults) or request it be put into host memory (via fname:vkGetQueryPoolResults). [NOTE] .Note ==== If occluding geometry is not drawn first, samples can: pass the depth test, but still not be visible in a final image. ==== [[queries-pipestats]] == Pipeline Statistics Queries Pipeline statistics queries allow the application to sample a specified set of sname:VkPipeline counters. These counters are accumulated by Vulkan for a set of either drawing or dispatching commands while a pipeline statistics query is active. As such, pipeline statistics queries are available on queue families supporting either graphics or compute operations. The availability of pipeline statistics queries is indicated by the pname:pipelineStatisticsQuery member of the sname:VkPhysicalDeviceFeatures object (see fname:vkGetPhysicalDeviceFeatures and fname:vkCreateDevice for detecting and requesting this query type on a sname:VkDevice). A pipeline statistics query is begun and ended by calling fname:vkCmdBeginQuery and fname:vkCmdEndQuery, respectively. When a pipeline statistics query begins, all statistics counters are set to zero. While the query is active, the pipeline type determines which set of statistics are available, but these must: be configured on the query pool when it is created. If a statistic counter is issued on a command buffer that does not support the corresponding operation, the value of that counter is undefined: after the query has been made available. At least one statistic counter relevant to the operations supported on the recording command buffer must: be enabled. [open,refpage='VkQueryPipelineStatisticFlagBits',desc='Bitmask specifying queried pipeline statistics',type='enums'] -- Bits which can: be set in slink:VkQueryPoolCreateInfo::pname:pipelineStatistics for query pools and in slink:VkCommandBufferInheritanceInfo::pname:pipelineStatistics for secondary command buffers, individually enabling pipeline statistics counters, are: include::{generated}/api/enums/VkQueryPipelineStatisticFlagBits.adoc[] * ename:VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_VERTICES_BIT specifies that queries managed by the pool will count the number of vertices processed by the <> stage. Vertices corresponding to incomplete primitives may: contribute to the count. * ename:VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_PRIMITIVES_BIT specifies that queries managed by the pool will count the number of primitives processed by the <> stage. If primitive restart is enabled, restarting the primitive topology has no effect on the count. Incomplete primitives may: be counted. * ename:VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of vertex shader invocations. This counter's value is incremented each time a vertex shader is <>. * ename:VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of geometry shader invocations. This counter's value is incremented each time a geometry shader is <>. In the case of <>, the geometry shader invocations count is incremented for each separate instanced invocation. * ename:VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_PRIMITIVES_BIT specifies that queries managed by the pool will count the number of primitives generated by geometry shader invocations. The counter's value is incremented each time the geometry shader emits a primitive. Restarting primitive topology using the SPIR-V instructions code:OpEndPrimitive or code:OpEndStreamPrimitive has no effect on the geometry shader output primitives count. * ename:VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of primitives processed by the <> stage of the pipeline. The counter's value is incremented each time a primitive reaches the primitive clipping stage. * ename:VK_QUERY_PIPELINE_STATISTIC_CLIPPING_PRIMITIVES_BIT specifies that queries managed by the pool will count the number of primitives output by the <> stage of the pipeline. The counter's value is incremented each time a primitive passes the primitive clipping stage. The actual number of primitives output by the primitive clipping stage for a particular input primitive is implementation-dependent but must: satisfy the following conditions: ** If at least one vertex of the input primitive lies inside the clipping volume, the counter is incremented by one or more. ** Otherwise, the counter is incremented by zero or more. * ename:VK_QUERY_PIPELINE_STATISTIC_FRAGMENT_SHADER_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of fragment shader invocations. The counter's value is incremented each time the fragment shader is <>. * ename:VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_CONTROL_SHADER_PATCHES_BIT specifies that queries managed by the pool will count the number of patches processed by the tessellation control shader. The counter's value is incremented once for each patch for which a tessellation control shader is <>. * ename:VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of invocations of the tessellation evaluation shader. The counter's value is incremented each time the tessellation evaluation shader is <>. * ename:VK_QUERY_PIPELINE_STATISTIC_COMPUTE_SHADER_INVOCATIONS_BIT specifies that queries managed by the pool will count the number of compute shader invocations. The counter's value is incremented every time the compute shader is invoked. Implementations may: skip the execution of certain compute shader invocations or execute additional compute shader invocations for implementation-dependent reasons as long as the results of rendering otherwise remain unchanged. ifdef::VK_EXT_mesh_shader[] * ename:VK_QUERY_PIPELINE_STATISTIC_TASK_SHADER_INVOCATIONS_BIT_EXT specifies that queries managed by the pool will count the number of task shader invocations. The counter's value is incremented every time the task shader is invoked. * ename:VK_QUERY_PIPELINE_STATISTIC_MESH_SHADER_INVOCATIONS_BIT_EXT specifies that queries managed by the pool will count the number of mesh shader invocations. The counter's value is incremented every time the mesh shader is invoked. endif::VK_EXT_mesh_shader[] These values are intended to measure relative statistics on one implementation. Various device architectures will count these values differently. Any or all counters may: be affected by the issues described in <>. ifdef::VK_EXT_mesh_shader,VK_NV_mesh_shader[] This counting difference is especially true if the pipeline contains mesh or task shaders, which may affect several of the counters in unexpected ways. endif::VK_EXT_mesh_shader,VK_NV_mesh_shader[] [NOTE] .Note ==== For example, tile-based rendering devices may: need to replay the scene multiple times, affecting some of the counts. ==== If a pipeline has pname:rasterizerDiscardEnable enabled, implementations may: discard primitives after the final <>. As a result, if pname:rasterizerDiscardEnable is enabled, the clipping input and output primitives counters may: not be incremented. When a pipeline statistics query finishes, the result for that query is marked as available. The application can: copy the result to a buffer (via fname:vkCmdCopyQueryPoolResults), or request it be put into host memory (via fname:vkGetQueryPoolResults). -- [open,refpage='VkQueryPipelineStatisticFlags',desc='Bitmask of VkQueryPipelineStatisticFlagBits',type='flags'] -- include::{generated}/api/flags/VkQueryPipelineStatisticFlags.adoc[] tname:VkQueryPipelineStatisticFlags is a bitmask type for setting a mask of zero or more elink:VkQueryPipelineStatisticFlagBits. -- [[queries-timestamps]] == Timestamp Queries _Timestamps_ provide applications with a mechanism for timing the execution of commands. A timestamp is an integer value generated by the sname:VkPhysicalDevice. Unlike other queries, timestamps do not operate over a range, and so do not use flink:vkCmdBeginQuery or flink:vkCmdEndQuery. The mechanism is built around a set of commands that allow the application to tell the sname:VkPhysicalDevice to write timestamp values to a <> and then either read timestamp values on the host (using flink:vkGetQueryPoolResults) or copy timestamp values to a sname:VkBuffer (using flink:vkCmdCopyQueryPoolResults). The application can: then compute differences between timestamps to determine execution time. The number of valid bits in a timestamp value is determined by the sname:VkQueueFamilyProperties::pname:timestampValidBits property of the queue on which the timestamp is written. Timestamps are supported on any queue which reports a non-zero value for pname:timestampValidBits via flink:vkGetPhysicalDeviceQueueFamilyProperties. If the <> limit is ename:VK_TRUE, timestamps are supported by every queue family that supports either graphics or compute operations (see slink:VkQueueFamilyProperties). The number of nanoseconds it takes for a timestamp value to be incremented by 1 can: be obtained from sname:VkPhysicalDeviceLimits::pname:timestampPeriod after a call to fname:vkGetPhysicalDeviceProperties. ifdef::VK_VERSION_1_3,VK_KHR_synchronization2[] [open,refpage='vkCmdWriteTimestamp2',desc='Write a device timestamp into a query object',type='protos',alias='vkCmdWriteTimestamp2KHR'] -- :refpage: vkCmdWriteTimestamp2 To request a timestamp and write the value to memory, call: ifdef::VK_VERSION_1_3[] include::{generated}/api/protos/vkCmdWriteTimestamp2.adoc[] endif::VK_VERSION_1_3[] ifdef::VK_VERSION_1_3+VK_KHR_synchronization2[or the equivalent command] ifdef::VK_KHR_synchronization2[] include::{generated}/api/protos/vkCmdWriteTimestamp2KHR.adoc[] endif::VK_KHR_synchronization2[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:stage specifies a stage of the pipeline. * pname:queryPool is the query pool that will manage the timestamp. * pname:query is the query within the query pool that will contain the timestamp. When fname:vkCmdWriteTimestamp2 is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and writes a timestamp to a query pool. The first <> includes all commands that occur earlier in <>. The synchronization scope is limited to operations on the pipeline stage specified by pname:stage. The second <> includes only the timestamp write operation. [NOTE] .Note ==== Implementations may write the timestamp at any stage that is <> than pname:stage. ==== Any timestamp write that <> another timestamp write in the same submission must: not have a lower value unless its value overflows the maximum supported integer bit width of the query. ifdef::VK_EXT_calibrated_timestamps[] If `apiext:VK_EXT_calibrated_timestamps` is enabled, this extends to timestamp writes across all submissions on the same logical device: any timestamp write that <> another must: not have a lower value unless its value overflows the maximum supported integer bit width of the query. Timestamps written by this command must: be in the ename:VK_TIME_DOMAIN_DEVICE_EXT <>. endif::VK_EXT_calibrated_timestamps[] If an overflow occurs, the timestamp value must: wrap back to zero. [NOTE] .Note ==== Comparisons between timestamps should be done between timestamps where they are guaranteed to not decrease. For example, subtracting an older timestamp from a newer one to determine the execution time of a sequence of commands is only a reliable measurement if the two timestamp writes were performed in the same ifdef::VK_EXT_calibrated_timestamps[] submission, or if the writes were performed on the same logical device and `apiext:VK_EXT_calibrated_timestamps` is enabled. endif::VK_EXT_calibrated_timestamps[] ifndef::VK_EXT_calibrated_timestamps[] submission. endif::VK_EXT_calibrated_timestamps[] ==== ifdef::VK_VERSION_1_1,VK_KHR_multiview[] If fname:vkCmdWriteTimestamp2 is called while executing a render pass instance that has multiview enabled, the timestamp uses [eq]#N# consecutive query indices in the query pool (starting at pname:query) where [eq]#N# is the number of bits set in the view mask of the subpass the command is executed in. The resulting query values are determined by an implementation-dependent choice of one of the following behaviors: * The first query is a timestamp value and (if more than one bit is set in the view mask) zero is written to the remaining queries. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the difference between the first query written by each command. * All [eq]#N# queries are timestamp values. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the sum of the difference between corresponding queries written by each command. The difference between corresponding queries may: be the execution time of a single view. In either case, the application can: sum the differences between all [eq]#N# queries to determine the total execution time. endif::VK_VERSION_1_1,VK_KHR_multiview[] .Valid Usage **** :stageMaskName: stage include::{chapters}/commonvalidity/stage_mask_2_common.adoc[] * [[VUID-vkCmdWriteTimestamp2-synchronization2-03858]] The <> feature must: be enabled * [[VUID-vkCmdWriteTimestamp2-stage-03859]] pname:stage must: only include a single pipeline stage * [[VUID-vkCmdWriteTimestamp2-stage-03860]] pname:stage must: only include stages valid for the queue family that was used to create the command pool that pname:commandBuffer was allocated from * [[VUID-vkCmdWriteTimestamp2-queryPool-03861]] pname:queryPool must: have been created with a pname:queryType of ename:VK_QUERY_TYPE_TIMESTAMP * [[VUID-vkCmdWriteTimestamp2-timestampValidBits-03863]] The command pool's queue family must: support a non-zero pname:timestampValidBits * [[VUID-vkCmdWriteTimestamp2-query-04903]] pname:query must: be less than the number of queries in pname:queryPool * [[VUID-vkCmdWriteTimestamp2-None-03864]] All queries used by the command must: be _unavailable_ ifdef::VK_VERSION_1_1,VK_KHR_multiview[] * [[VUID-vkCmdWriteTimestamp2-query-03865]] If fname:vkCmdWriteTimestamp2 is called within a render pass instance, the sum of pname:query and the number of bits set in the current subpass's view mask must: be less than or equal to the number of queries in pname:queryPool endif::VK_VERSION_1_1,VK_KHR_multiview[] **** include::{generated}/validity/protos/vkCmdWriteTimestamp2.adoc[] -- endif::VK_VERSION_1_3,VK_KHR_synchronization2[] [open,refpage='vkCmdWriteTimestamp',desc='Write a device timestamp into a query object',type='protos'] -- :refpage: vkCmdWriteTimestamp To request a timestamp and write the value to memory, call: include::{generated}/api/protos/vkCmdWriteTimestamp.adoc[] * pname:commandBuffer is the command buffer into which the command will be recorded. * pname:pipelineStage is a elink:VkPipelineStageFlagBits value, specifying a stage of the pipeline. * pname:queryPool is the query pool that will manage the timestamp. * pname:query is the query within the query pool that will contain the timestamp. When fname:vkCmdWriteTimestamp is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and writes a timestamp to a query pool. The first <> includes all commands that occur earlier in <>. The synchronization scope is limited to operations on the pipeline stage specified by pname:pipelineStage. The second <> includes only the timestamp write operation. [NOTE] .Note ==== Implementations may write the timestamp at any stage that is <> than pname:stage. ==== Any timestamp write that <> another timestamp write in the same submission must: not have a lower value unless its value overflows the maximum supported integer bit width of the query. ifdef::VK_EXT_calibrated_timestamps[] If `apiext:VK_EXT_calibrated_timestamps` is enabled, this extends to timestamp writes across all submissions on the same logical device: any timestamp write that <> another must: not have a lower value unless its value overflows the maximum supported integer bit width of the query. Timestamps written by this command must: be in the ename:VK_TIME_DOMAIN_DEVICE_EXT <>. endif::VK_EXT_calibrated_timestamps[] If an overflow occurs, the timestamp value must: wrap back to zero. [NOTE] .Note ==== Comparisons between timestamps should be done between timestamps where they are guaranteed to not decrease. For example, subtracting an older timestamp from a newer one to determine the execution time of a sequence of commands is only a reliable measurement if the two timestamp writes were performed in the same ifdef::VK_EXT_calibrated_timestamps[] submission, or if the writes were performed on the same logical device and `apiext:VK_EXT_calibrated_timestamps` is enabled. endif::VK_EXT_calibrated_timestamps[] ifndef::VK_EXT_calibrated_timestamps[] submission. endif::VK_EXT_calibrated_timestamps[] ==== ifdef::VK_VERSION_1_1,VK_KHR_multiview[] If fname:vkCmdWriteTimestamp is called while executing a render pass instance that has multiview enabled, the timestamp uses [eq]#N# consecutive query indices in the query pool (starting at pname:query) where [eq]#N# is the number of bits set in the view mask of the subpass the command is executed in. The resulting query values are determined by an implementation-dependent choice of one of the following behaviors: * The first query is a timestamp value and (if more than one bit is set in the view mask) zero is written to the remaining queries. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the difference between the first query written by each command. * All [eq]#N# queries are timestamp values. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the sum of the difference between corresponding queries written by each command. The difference between corresponding queries may: be the execution time of a single view. In either case, the application can: sum the differences between all [eq]#N# queries to determine the total execution time. endif::VK_VERSION_1_1,VK_KHR_multiview[] .Valid Usage **** include::{chapters}/commonvalidity/pipeline_stage_common.adoc[] * [[VUID-vkCmdWriteTimestamp-queryPool-01416]] pname:queryPool must: have been created with a pname:queryType of ename:VK_QUERY_TYPE_TIMESTAMP * [[VUID-vkCmdWriteTimestamp-timestampValidBits-00829]] The command pool's queue family must: support a non-zero pname:timestampValidBits * [[VUID-vkCmdWriteTimestamp-query-04904]] pname:query must: be less than the number of queries in pname:queryPool * [[VUID-vkCmdWriteTimestamp-None-00830]] All queries used by the command must: be _unavailable_ ifdef::VK_VERSION_1_1,VK_KHR_multiview[] * [[VUID-vkCmdWriteTimestamp-query-00831]] If fname:vkCmdWriteTimestamp is called within a render pass instance, the sum of pname:query and the number of bits set in the current subpass's view mask must: be less than or equal to the number of queries in pname:queryPool endif::VK_VERSION_1_1,VK_KHR_multiview[] **** include::{generated}/validity/protos/vkCmdWriteTimestamp.adoc[] -- ifdef::VK_KHR_performance_query[] include::{chapters}/VK_KHR_performance_query/queriesperformance.adoc[] endif::VK_KHR_performance_query[] ifdef::VK_EXT_transform_feedback[] [[queries-transform-feedback]] == Transform Feedback Queries Transform feedback queries track the number of primitives attempted to be written and actually written, by the vertex stream being captured, to a transform feedback buffer. This query is updated during drawing commands while transform feedback is active. The number of primitives actually written will be less than the number attempted to be written if the bound transform feedback buffer size was too small for the number of primitives actually drawn. Primitives are not written beyond the bound range of the transform feedback buffer. A transform feedback query is begun and ended by calling fname:vkCmdBeginQuery and fname:vkCmdEndQuery, respectively to query for vertex stream zero. fname:vkCmdBeginQueryIndexedEXT and fname:vkCmdEndQueryIndexedEXT can: be used to begin and end transform feedback queries for any supported vertex stream. When a transform feedback query begins, the count of primitives written and primitives needed starts from zero. For each drawing command, the count is incremented as vertex attribute outputs are captured to the transform feedback buffers while transform feedback is active. When a transform feedback query finishes, the result for that query is marked as available. The application can: then either copy the result to a buffer (via fname:vkCmdCopyQueryPoolResults) or request it be put into host memory (via fname:vkGetQueryPoolResults). endif::VK_EXT_transform_feedback[] ifdef::VK_EXT_primitives_generated_query[] [[queries-primitives-generated]] == Primitives Generated Queries When a generated primitive query for a vertex stream is active, the primitives-generated count is incremented every time a primitive emitted to that stream reaches the transform feedback stage, whether or not transform feedback is active. A primitives generated query is begun and ended by calling fname:vkCmdBeginQuery and fname:vkCmdEndQuery, respectively to query for vertex stream zero. fname:vkCmdBeginQueryIndexedEXT and fname:vkCmdEndQueryIndexedEXT can: be used to begin and end primitives generated queries for any supported vertex stream. When a primitives generated query begins, the count of primitives generated starts from zero. When a primitives generated query finishes, the result for that query is marked as available. The application can: then either copy the result to a buffer (via fname:vkCmdCopyQueryPoolResults) or request it be put into host memory (via fname:vkGetQueryPoolResults). [NOTE] .Note ==== The result of this query is typically identical to ename:VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT, but the primitives generated query is deterministic, i.e. it must be identical to the number of primitives processed. ename:VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT may vary for implementation-dependent reasons, e.g. the same primitive may be processed multiple times for purposes of clipping. ==== endif::VK_EXT_primitives_generated_query[] ifdef::VK_EXT_mesh_shader[] [[queries-mesh-shader]] == Mesh Shader Queries When a generated mesh primitives query is active, the mesh-primitives-generated count is incremented every time a primitive emitted from the mesh shader stage reaches the fragment shader stage. When a generated mesh primitives query begins, the mesh-primitives-generated count starts from zero. Mesh and task shader pipeline statistics queries function the same way that invocation queries work for other shader stages, counting the number of times the respective shader stage has been run. When the statistics query begins, the invocation counters start from zero. endif::VK_EXT_mesh_shader[] ifdef::VK_INTEL_performance_query[] include::{chapters}/VK_INTEL_performance_query/queries.adoc[] endif::VK_INTEL_performance_query[] ifdef::VK_KHR_video_queue[] [[queries-result-status-only]] == Result Status Queries Result status queries serve a single purpose: allowing the application to determine whether a set of operations have completed successfully or not, as indicated by the elink:VkQueryResultStatusKHR value written when retrieving the result of a query using the ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR flag. Unlike other query types, result status queries do not track or maintain any other data beyond the completion status, thus no other data is written when retrieving their results. Support for result status queries is indicated by slink:VkQueueFamilyQueryResultStatusPropertiesKHR::pname:queryResultStatusSupport , as returned by flink:vkGetPhysicalDeviceQueueFamilyProperties2 for the queue family in question. endif::VK_KHR_video_queue[] ifdef::VK_KHR_video_encode_queue[] [[queries-video-encode-feedback]] == Video Encode Feedback Queries Video encode feedback queries allow the application to capture feedback values generated by video encode operations. As such, video encode feedback queries are available on queue families supporting video encode operations. The availability of individual video encode feedback values is indicated by the bits of slink:VkVideoEncodeCapabilitiesKHR::pname:supportedEncodeFeedbackFlags, as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the <> the queries are intended to be used with. The set of enabled video encode feedback values must: be configured on the query pool when it is created using the pname:encodeFeedbackFlags member of the slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR included in the pname:pNext chain of slink:VkQueryPoolCreateInfo. [open,refpage='VkQueryPoolVideoEncodeFeedbackCreateInfoKHR',desc='Structure specifying enabled video encode feedback values',type='structs'] -- The sname:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR structure is defined as: include::{generated}/api/structs/VkQueryPoolVideoEncodeFeedbackCreateInfoKHR.adoc[] * pname:sType is a elink:VkStructureType value identifying this structure. * pname:pNext is `NULL` or a pointer to a structure extending this structure. * pname:encodeFeedbackFlags is a bitmask of elink:VkVideoEncodeFeedbackFlagBitsKHR values specifying the set of enabled video encode feedback values captured by queries of the new pool. include::{generated}/validity/structs/VkQueryPoolVideoEncodeFeedbackCreateInfoKHR.adoc[] -- [open,refpage='VkVideoEncodeFeedbackFlagBitsKHR',desc='Bits specifying queried video encode feedback values',type='enums'] -- Bits which can: be set in slink:VkQueryPoolVideoEncodeFeedbackCreateInfoKHR::pname:encodeFeedbackFlags for video encode feedback query pools are: include::{generated}/api/enums/VkVideoEncodeFeedbackFlagBitsKHR.adoc[] * ename:VK_VIDEO_ENCODE_FEEDBACK_BITSTREAM_BUFFER_OFFSET_BIT_KHR specifies that queries managed by the pool will capture the byte offset of the bitstream data written by the video encode operation to the bitstream buffer specified in slink:VkVideoEncodeInfoKHR::pname:dstBuffer relative to the offset specified in slink:VkVideoEncodeInfoKHR::pname:dstBufferOffset. * ename:VK_VIDEO_ENCODE_FEEDBACK_BITSTREAM_BYTES_WRITTEN_BIT_KHR specifies that queries managed by the pool will capture the number of bytes written by the video encode operation to the bitstream buffer specified in slink:VkVideoEncodeInfoKHR::pname:dstBuffer. * ename:VK_VIDEO_ENCODE_FEEDBACK_BITSTREAM_HAS_OVERRIDES_BIT_KHR specifies that queries managed by the pool will capture a boolean value indicating that the data written to the bitstream buffer specified in slink:VkVideoEncodeInfoKHR::pname:dstBuffer contains overridden parameters. When retrieving the results of video encode feedback queries, the values corresponding to each enabled video encode feedback are written in the order of the bits defined above, followed by an optional value indicating availability or result status if ename:VK_QUERY_RESULT_WITH_AVAILABILITY_BIT or ename:VK_QUERY_RESULT_WITH_STATUS_BIT_KHR is specified, respectively. -- [open,refpage='VkVideoEncodeFeedbackFlagsKHR',desc='Bitmask of VkVideoEncodeFeedbackFlagBitsKHR',type='flags'] -- include::{generated}/api/flags/VkVideoEncodeFeedbackFlagsKHR.adoc[] tname:VkVideoEncodeFeedbackFlagsKHR is a bitmask type for setting a mask of zero or more elink:VkVideoEncodeFeedbackFlagBitsKHR. -- endif::VK_KHR_video_encode_queue[]