[[debugging-debug-utils]] == Debug Utilities Vulkan provides flexible debugging utilities for debugging an application. The <> section describes how to associate either a name or binary data with a specific Vulkan object. The <> section describes how to annotate and group the work submitted to a queue. The <> section describes how to associate logical elements of the scene with commands in a slink:VkCommandBuffer. The <> section describes how to create debug messenger objects associated with an application supplied callback to capture debug messages from a variety of Vulkan components. [[debugging-object-debug-annotation]] === Object Debug Annotation It can be useful for an application to provide its own content relative to a specific Vulkan object. The following commands allow application developers to associate user-defined information with Vulkan objects. [[debugging-object-naming]] ==== Object Naming An object can be provided a user-defined name by calling fname:vkSetDebugUtilsObjectNameEXT as defined below. [open,refpage='vkSetDebugUtilsObjectNameEXT',desc='Give a user-friendly name to an object',type='protos'] -- include::../api/protos/vkSetDebugUtilsObjectNameEXT.txt[] * pname:device is the device that created the object. * pname:pNameInfo is a pointer to an instance of the slink:VkDebugUtilsObjectNameInfoEXT structure specifying the parameters of the name to set on the object. include::../validity/protos/vkSetDebugUtilsObjectNameEXT.txt[] -- [open,refpage='VkDebugUtilsObjectNameInfoEXT',desc='Specify parameters of a name to give to an object',type='structs'] -- The sname:VkDebugUtilsObjectNameInfoEXT structure is defined as: include::../api/structs/VkDebugUtilsObjectNameInfoEXT.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:objectType is a elink:VkObjectType specifying the type of the object to be named. * pname:objectHandle is the object to be named. * pname:pObjectName is a null-terminated UTF-8 string specifying the name to apply to pname:objectHandle. Applications may: change the name associated with an object simply by calling fname:vkSetDebugUtilsObjectNameEXT again with a new string. If pname:pObjectName is an empty string, then any previously set name is removed. .Valid Usage **** * [[VUID-VkDebugUtilsObjectNameInfoEXT-objectType-01905]] pname:objectType must: not be ename:VK_OBJECT_TYPE_UNKNOWN * [[VUID-VkDebugUtilsObjectNameInfoEXT-objectHandle-01906]] pname:objectHandle must: not be dlink:VK_NULL_HANDLE * [[VUID-VkDebugUtilsObjectNameInfoEXT-objectHandle-01907]] pname:objectHandle must: be a Vulkan object of the type associated with pname:objectType as defined in <>. **** include::../validity/structs/VkDebugUtilsObjectNameInfoEXT.txt[] -- [[debugging-object-data-association]] ==== Object Data Association In addition to setting a name for an object, debugging and validation layers may: have uses for additional binary data on a per-object basis that have no other place in the Vulkan API. For example, a sname:VkShaderModule could have additional debugging data attached to it to aid in offline shader tracing. Additional data can be attached to an object by calling fname:vkSetDebugUtilsObjectTagEXT as defined below. [open,refpage='vkSetDebugUtilsObjectTagEXT',desc='Attach arbitrary data to an object',type='protos'] -- include::../api/protos/vkSetDebugUtilsObjectTagEXT.txt[] * pname:device is the device that created the object. * pname:pTagInfo is a pointer to an instance of the slink:VkDebugUtilsObjectTagInfoEXT structure specifying the parameters of the tag to attach to the object. include::../validity/protos/vkSetDebugUtilsObjectTagEXT.txt[] -- [open,refpage='VkDebugUtilsObjectTagInfoEXT',desc='Specify parameters of a tag to attach to an object',type='structs'] -- The sname:VkDebugUtilsObjectTagInfoEXT structure is defined as: include::../api/structs/VkDebugUtilsObjectTagInfoEXT.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:objectType is a elink:VkObjectType specifying the type of the object to be named. * pname:objectHandle is the object to be tagged. * pname:tagName is a numerical identifier of the tag. * pname:tagSize is the number of bytes of data to attach to the object. * pname:pTag is an array of pname:tagSize bytes containing the data to be associated with the object. The pname:tagName parameter gives a name or identifier to the type of data being tagged. This can be used by debugging layers to easily filter for only data that can be used by that implementation. .Valid Usage **** * [[VUID-VkDebugUtilsObjectTagInfoEXT-objectType-01908]] pname:objectType must: not be ename:VK_OBJECT_TYPE_UNKNOWN * [[VUID-VkDebugUtilsObjectTagInfoEXT-objectHandle-01909]] pname:objectHandle must: not be dlink:VK_NULL_HANDLE * [[VUID-VkDebugUtilsObjectTagInfoEXT-objectHandle-01910]] pname:objectHandle must: be a Vulkan object of the type associated with pname:objectType as defined in <>. **** include::../validity/structs/VkDebugUtilsObjectTagInfoEXT.txt[] -- [[debugging-queue-labels]] === Queue Labels All Vulkan work must be submitted using queues. It is possible for an application to use multiple queues, each containing multiple command buffers, when performing work. It can be useful to identify which queue, or even where in a queue, something has occurred. To begin identifying a region using a debug label inside a queue, you may use the flink:vkQueueBeginDebugUtilsLabelEXT command. Then, when the region of interest has passed, you may end the label region using flink:vkQueueEndDebugUtilsLabelEXT. Additionally, a single debug label may be inserted at any time using flink:vkQueueInsertDebugUtilsLabelEXT. [open,refpage='vkQueueBeginDebugUtilsLabelEXT',desc='Open a queue debug label region',type='protos'] -- A queue debug label region is opened by calling: include::../api/protos/vkQueueBeginDebugUtilsLabelEXT.txt[] * pname:queue is the queue in which to start a debug label region. * pname:pLabelInfo is a pointer to an instance of the slink:VkDebugUtilsLabelEXT structure specifying the parameters of the label region to open. include::../validity/protos/vkQueueBeginDebugUtilsLabelEXT.txt[] -- [open,refpage='VkDebugUtilsLabelEXT',desc='Specify parameters of a label region',type='structs'] -- The sname:VkDebugUtilsLabelEXT structure is defined as: include::../api/structs/VkDebugUtilsLabelEXT.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:pLabelName is a pointer to a null-terminated UTF-8 string that contains the name of the label. * pname:color is an optional RGBA color value that can be associated with the label. A particular implementation may: choose to ignore this color value. The values contain RGBA values in order, in the range 0.0 to 1.0. If all elements in pname:color are set to 0.0 then it is ignored. include::../validity/structs/VkDebugUtilsLabelEXT.txt[] -- [open,refpage='vkQueueEndDebugUtilsLabelEXT',desc='Close a queue debug label region',type='protos'] -- A queue debug label region is closed by calling: include::../api/protos/vkQueueEndDebugUtilsLabelEXT.txt[] * pname:queue is the queue in which a debug label region should be closed. The calls to flink:vkQueueBeginDebugUtilsLabelEXT and flink:vkQueueEndDebugUtilsLabelEXT must: be matched and balanced. .Valid Usage **** * [[VUID-vkQueueEndDebugUtilsLabelEXT-None-01911]] There must: be an outstanding fname:vkQueueBeginDebugUtilsLabelEXT command prior to the fname:vkQueueEndDebugUtilsLabelEXT on the queue **** include::../validity/protos/vkQueueEndDebugUtilsLabelEXT.txt[] -- [open,refpage='vkQueueInsertDebugUtilsLabelEXT',desc='Insert a label into a queue',type='protos'] -- A single label can be inserted into a queue by calling: include::../api/protos/vkQueueInsertDebugUtilsLabelEXT.txt[] * pname:queue is the queue into which a debug label will be inserted. * pname:pLabelInfo is a pointer to an instance of the slink:VkDebugUtilsLabelEXT structure specifying the parameters of the label to insert. include::../validity/protos/vkQueueInsertDebugUtilsLabelEXT.txt[] -- [[debugging-command-buffer-labels]] === Command Buffer Labels Typical Vulkan applications will submit many command buffers in each frame, with each command buffer containing a large number of individual commands. Being able to logically annotate regions of command buffers that belong together as well as hierarchically subdivide the frame is important to a developer's ability to navigate the commands viewed holistically. To identify the beginning of a debug label region in a command buffer, flink:vkCmdBeginDebugUtilsLabelEXT can: be used as defined below. To indicate the end of a debug label region in a command buffer, flink:vkCmdEndDebugUtilsLabelEXT can: be used. To insert a single command buffer debug label inside of a command buffer, flink:vkCmdInsertDebugUtilsLabelEXT can: be used as defined below. [open,refpage='vkCmdBeginDebugUtilsLabelEXT',desc='Open a command buffer debug label region',type='protos'] -- A command buffer debug label region can be opened by calling: include::../api/protos/vkCmdBeginDebugUtilsLabelEXT.txt[] * pname:commandBuffer is the command buffer into which the command is recorded. * pname:pLabelInfo is a pointer to an instance of the slink:VkDebugUtilsLabelEXT structure specifying the parameters of the label region to open. include::../validity/protos/vkCmdBeginDebugUtilsLabelEXT.txt[] -- [open,refpage='vkCmdEndDebugUtilsLabelEXT',desc='Close a command buffer label region',type='protos'] -- A command buffer label region can be closed by calling: include::../api/protos/vkCmdEndDebugUtilsLabelEXT.txt[] * pname:commandBuffer is the command buffer into which the command is recorded. An application may: open a debug label region in one command buffer and close it in another, or otherwise split debug label regions across multiple command buffers or multiple queue submissions. When viewed from the linear series of submissions to a single queue, the calls to flink:vkCmdBeginDebugUtilsLabelEXT and flink:vkCmdEndDebugUtilsLabelEXT must: be matched and balanced. .Valid Usage **** * [[VUID-vkCmdEndDebugUtilsLabelEXT-commandBuffer-01912]] There must: be an outstanding fname:vkCmdBeginDebugUtilsLabelEXT command prior to the fname:vkCmdEndDebugUtilsLabelEXT on the queue that pname:commandBuffer is submitted to * [[VUID-vkCmdEndDebugUtilsLabelEXT-commandBuffer-01913]] If pname:commandBuffer is a secondary command buffer, there must: be an outstanding fname:vkCmdBeginDebugUtilsLabelEXT command recorded to pname:commandBuffer that has not previously been ended by a call to fname:vkCmdEndDebugUtilsLabelEXT. **** include::../validity/protos/vkCmdEndDebugUtilsLabelEXT.txt[] -- [open,refpage='vkCmdInsertDebugUtilsLabelEXT',desc='Insert a label into a command buffer',type='protos'] -- A single debug label can be inserted into a command buffer by calling: include::../api/protos/vkCmdInsertDebugUtilsLabelEXT.txt[] * pname:commandBuffer is the command buffer into which the command is recorded. * pname:pInfo is a pointer to an instance of the slink:VkDebugUtilsLabelEXT structure specifying the parameters of the label to insert. include::../validity/protos/vkCmdInsertDebugUtilsLabelEXT.txt[] -- [[debugging-debug-messengers]] === Debug Messengers Vulkan allows an application to register multiple callbacks with any Vulkan component wishing to report debug information. Some callbacks may log the information to a file, others may cause a debug break point or other application defined behavior. A primary producer of callback messages are the validation layers. An application can: register callbacks even when no validation layers are enabled, but they will only be called for the Vulkan loader and, if implemented, other layer and driver events. [open,refpage='VkDebugUtilsMessengerEXT',desc='Opaque handle to a debug messenger object',type='structs'] -- A sname:VkDebugUtilsMessengerEXT is a messenger object which handles passing along debug messages to a provided debug callback. include::../api/handles/VkDebugUtilsMessengerEXT.txt[] The debug messenger will provide detailed feedback on the application's use of Vulkan when events of interest occur. When an event of interest does occur, the debug messenger will submit a debug message to the debug callback that was provided during its creation. Additionally, the debug messenger is responsible with filtering out debug messages that the callback is not interested in and will only provide desired debug messages. -- [open,refpage='vkCreateDebugUtilsMessengerEXT',desc='Create a debug messenger object',type='protos'] -- A debug messenger triggers a debug callback with a debug message when an event of interest occurs. To create a debug messenger which will trigger a debug callback, call: include::../api/protos/vkCreateDebugUtilsMessengerEXT.txt[] * pname:instance the instance the messenger will be used with. * pname:pCreateInfo points to a slink:VkDebugUtilsMessengerCreateInfoEXT structure which contains the callback pointer as well as defines the conditions under which this messenger will trigger the callback. * pname:pAllocator controls host memory allocation as described in the <> chapter. * pname:pMessenger is a pointer to record the sname:VkDebugUtilsMessengerEXT object created. include::../validity/protos/vkCreateDebugUtilsMessengerEXT.txt[] -- [open,refpage='VkDebugUtilsMessengerCreateInfoEXT',desc='Structure specifying parameters of a newly created debug messenger',type='structs'] -- The definition of sname:VkDebugUtilsMessengerCreateInfoEXT is: include::../api/structs/VkDebugUtilsMessengerCreateInfoEXT.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:flags is 0 and reserved for future use. * pname:messageSeverity is a bitmask of elink:VkDebugUtilsMessageSeverityFlagBitsEXT specifying which severity of event(s) will cause this callback to be called. * pname:messageTypes is a bitmask of elink:VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) will cause this callback to be called. * pname:pfnUserCallback is the application callback function to call. * pname:pUserData is user data to be passed to the callback. For each sname:VkDebugUtilsMessengerEXT that is created the sname:VkDebugUtilsMessengerCreateInfoEXT::pname:messageSeverity and sname:VkDebugUtilsMessengerCreateInfoEXT::pname:messageTypes determine when that sname:VkDebugUtilsMessengerCreateInfoEXT::pname:pfnUserCallback is called. The process to determine if the user's pfnUserCallback is triggered when an event occurs is as follows: . The implementation will perform a bitwise AND of the event's elink:VkDebugUtilsMessageSeverityFlagBitsEXT with the pname:messageSeverity provided during creation of the slink:VkDebugUtilsMessengerEXT object. .. If the value is 0, the message is skipped. . The implementation will perform bitwise AND of the event's elink:VkDebugUtilsMessageTypeFlagBitsEXT with the pname:messageType provided during the creation of the slink:VkDebugUtilsMessengerEXT object. .. If the value is 0, the message is skipped. . The callback will trigger a debug message for the current event The callback will come directly from the component that detected the event, unless some other layer intercepts the calls for its own purposes (filter them in a different way, log to a system error log, etc.). An application can: receive multiple callbacks if multiple sname:VkDebugUtilsMessengerEXT objects are created. A callback will always be executed in the same thread as the originating Vulkan call. A callback can: be called from multiple threads simultaneously (if the application is making Vulkan calls from multiple threads). .Valid Usage **** * [[VUID-VkDebugUtilsMessengerCreateInfoEXT-pfnUserCallback-01914]] pname:pfnUserCallback must: be a valid tlink:PFN_vkDebugUtilsMessengerCallbackEXT **** include::../validity/structs/VkDebugUtilsMessengerCreateInfoEXT.txt[] -- [open,refpage='VkDebugUtilsMessageSeverityFlagBitsEXT',desc='Bitmask specifying which severities of events cause a debug messenger callback',type='enums'] -- Bits which can: be set in slink:VkDebugUtilsMessengerCreateInfoEXT::pname:messageSeverity, specifying event severities which cause a debug messenger to call the callback, are: include::../api/enums/VkDebugUtilsMessageSeverityFlagBitsEXT.txt[] * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT specifies the most verbose output indicating all diagnostic messages from the Vulkan loader, layers, and drivers should be captured. * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT specifies an informational message such as resource details that may be handy when debugging an application. * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT specifies use of Vulkan that may: expose an app bug. Such cases may not be immediately harmful, such as a fragment shader outputting to a location with no attachment. Other cases may: point to behavior that is almost certainly bad when unintended such as using an image whose memory has not been filled. In general if you see a warning but you know that the behavior is intended/desired, then simply ignore the warning. * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT specifies that an error that may cause undefined results, including an application crash. -- [NOTE] .Note ==== The values of ename:VkDebugUtilsMessageSeverityFlagBitsEXT are sorted based on severity. The higher the flag value, the more severe the message. This allows for simple boolean operation comparisons when looking at ename:VkDebugUtilsMessageSeverityFlagBitsEXT values. For example: [source,c++] ---------------------------------------- if (messageSeverity >= VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT) { // Do something for warnings and errors } ---------------------------------------- In addition, space has been left between the enums to allow for later addition of new severities in between the existing values. ==== [open,refpage='VkDebugUtilsMessageTypeFlagBitsEXT',desc='Bitmask specifying which types of events cause a debug messenger callback',type='enums'] -- Bits which can: be set in slink:VkDebugUtilsMessengerCreateInfoEXT::pname:messageTypes, specifying event types which cause a debug messenger to call the callback, are: include::../api/enums/VkDebugUtilsMessageTypeFlagBitsEXT.txt[] * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT specifies that some general event has occurred. This is typically a non-specification, non-performance event. * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT specifies that something has occurred during validation against the Vulkan specification that may indicate invalid behavior. * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT specifies a potentially non-optimal use of Vulkan, e.g. using flink:vkCmdClearColorImage when setting slink:VkAttachmentDescription::pname:loadOp to ename:VK_ATTACHMENT_LOAD_OP_CLEAR would have worked. -- [open,refpage='PFN_vkDebugUtilsMessengerCallbackEXT',desc='Application-defined debug messenger callback function',type='funcpointers'] -- The prototype for the slink:VkDebugUtilsMessengerCreateInfoEXT::pname:pfnUserCallback function implemented by the application is: include::../api/funcpointers/PFN_vkDebugUtilsMessengerCallbackEXT.txt[] * pname:messageSeverity specifies the elink:VkDebugUtilsMessageSeverityFlagBitsEXT that triggered this callback. * pname:messageTypes specifies the elink:VkDebugUtilsMessageTypeFlagBitsEXT that triggered this callback. * pname:pCallbackData contains all the callback related data in the slink:VkDebugUtilsMessengerCallbackDataEXT structure. * pname:pUserData is the user data provided when the slink:VkDebugUtilsMessengerEXT was created. The callback must: not call flink:vkDestroyDebugUtilsMessengerEXT. The callback returns a basetype:VkBool32, which is interpreted in a layer-specified manner. The application should: always return ename:VK_FALSE. The ename:VK_TRUE value is reserved for use in layer development. -- [open,refpage='VkDebugUtilsMessengerCallbackDataEXT',desc='Structure specifying parameters returned to the callback',type='structs'] -- The definition of sname:VkDebugUtilsMessengerCallbackDataEXT is: include::../api/structs/VkDebugUtilsMessengerCallbackDataEXT.txt[] * pname:sType is the type of this structure. * pname:pNext is `NULL` or a pointer to an extension-specific structure. * pname:flags is 0 and reserved for future use. * pname:pMessageIdName is a null-terminated string that identifies the particular message ID that is associated with the provided message. If the message corresponds to a validation layer message, then this string may contain the portion of the Vulkan specification that is believed to have been violated. * pname:messageIdNumber is the ID number of the triggering message. If the message corresponds to a validation layer message, then this number is related to the internal number associated with the message being triggered. * pname:pMessage is a null-terminated string detailing the trigger conditions. * pname:queueLabelCount is a count of items contained in the pname:pQueueLabels array. * pname:pQueueLabels is NULL or a pointer to an array of slink:VkDebugUtilsLabelEXT active in the current sname:VkQueue at the time the callback was triggered. Refer to <> for more information. * pname:cmdBufLabelCount is a count of items contained in the pname:pCmdBufLabels array. * pname:pCmdBufLabels is NULL or a pointer to an array of slink:VkDebugUtilsLabelEXT active in the current sname:VkCommandBuffer at the time the callback was triggered. Refer to <> for more information. * pname:objectCount is a count of items contained in the pname:pObjects array. * pname:pObjects is a pointer to an array of slink:VkDebugUtilsObjectNameInfoEXT objects related to the detected issue. The array is roughly in order or importance, but the 0th element is always guaranteed to be the most important object for this message. [NOTE] .Note ==== This structure should only be considered valid during the lifetime of the triggered callback. ==== Since adding queue and command buffer labels behaves like pushing and popping onto a stack, the order of both pname:pQueueLabels and pname:pCmdBufLabels is based on the order the labels were defined. The result is that the first label in either pname:pQueueLabels or pname:pCmdBufLabels will be the first defined (and therefore the oldest) while the last label in each list will be the most recent. [NOTE] .Note ==== pname:pQueueLabels will only be non-NULL if one of the objects in pname:pObjects can be related directly to a defined sname:VkQueue which has had one or more labels associated with it. Likewise, pname:pCmdBufLabels will only be non-NULL if one of the objects in pname:pObjects can be related directly to a defined sname:VkCommandBuffer which has had one or more labels associated with it. Additionally, while command buffer labels allow for beginning and ending across different command buffers, the debug messaging framework cannot: guarantee that labels in pname:pCmdBufLables will contain those defined outside of the associated command buffer. This is partially due to the fact that the association of one command buffer with another may not have been defined at the time the debug message is triggered. ==== include::../validity/structs/VkDebugUtilsMessengerCallbackDataEXT.txt[] -- [open,refpage='vkSubmitDebugUtilsMessageEXT',desc='Inject a message into a debug stream',type='protos'] -- There may be times that a user wishes to intentionally submit a debug message. To do this, call: include::../api/protos/vkSubmitDebugUtilsMessageEXT.txt[] * pname:instance is the debug stream's slink:VkInstance. * pname:messageSeverity is the elink:VkDebugUtilsMessageSeverityFlagBitsEXT severity of this event/message. * pname:messageTypes is a bitmask of elink:VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) to identify with this message. * pname:pCallbackData contains all the callback related data in the slink:VkDebugUtilsMessengerCallbackDataEXT structure. The call will propagate through the layers and generate callback(s) as indicated by the message's flags. The parameters are passed on to the callback in addition to the pname:pUserData value that was defined at the time the messenger was registered. include::../validity/protos/vkSubmitDebugUtilsMessageEXT.txt[] -- [open,refpage='vkDestroyDebugUtilsMessengerEXT',desc='Destroy a debug messenger object',type='protos'] -- To destroy a sname:VkDebugUtilsMessengerEXT object, call: include::../api/protos/vkDestroyDebugUtilsMessengerEXT.txt[] * pname:instance the instance where the callback was created. * pname:messenger the slink:VkDebugUtilsMessengerEXT object to destroy. pname:messenger is an externally synchronized object and must: not be used on more than one thread at a time. This means that fname:vkDestroyDebugUtilsMessengerEXT must: not be called when a callback is active. * pname:pAllocator controls host memory allocation as described in the <> chapter. .Valid Usage **** * [[VUID-vkDestroyDebugUtilsMessengerEXT-messenger-01915]] If sname:VkAllocationCallbacks were provided when pname:messenger was created, a compatible set of callbacks must: be provided here * [[VUID-vkDestroyDebugUtilsMessengerEXT-messenger-01916]] If no sname:VkAllocationCallbacks were provided when pname:messenger was created, pname:pAllocator must: be `NULL` **** include::../validity/protos/vkDestroyDebugUtilsMessengerEXT.txt[] --