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# 6.2. CUPTI Callback API

Functions, types, and enums that implement the CUPTI Callback API.

## 6.2.1. Data Structures

CUpti_CallbackData

  Data passed into a runtime or driver API callback function.

CUpti_GraphData

  CUDA graphs data passed into a resource callback function.

CUpti_ModuleResourceData

  Module data passed into a resource callback function.

CUpti_NvtxData

  Data passed into a NVTX callback function.

CUpti_ResourceData

  Data passed into a resource callback function.

CUpti_StateData

  Data passed into a State callback function.

CUpti_StreamAttrData

  Stream attribute data passed into a resource callback function for CUPTI_CBID_RESOURCE_STREAM_ATTRIBUTE_CHANGED callback.

CUpti_SubscriberParams

  Params for cuptiSubscribe_v2.

CUpti_SynchronizeData

  Data passed into a synchronize callback function.

## 6.2.2. Macros

CUPTI_CALLBACK_STRUCT_SIZE

CUPTI_OLD_SUBSCRIBER_NAME_MIN_LEN

  The minimum size of the of the old subscriber name in bytes.

CUPTI_SUBSCRIBER_NAME_MAX_LEN

  The max size of the CUPTI subscriber name in bytes.

CUpti_SubscriberParams_STRUCT_SIZE

## 6.2.3. Enumerations

CUpti_ApiCallbackSite

  Specifies the point in an API call that a callback is issued.

CUpti_CallbackDomain

  Callback domains.

CUpti_CallbackIdResource

  Callback IDs for resource domain.

CUpti_CallbackIdState

  Callback IDs for state domain.

CUpti_CallbackIdSync

  Callback IDs for synchronization domain.

## 6.2.4. Functions

CUptiResult cuptiEnableAllDomains(uint32_t enable, CUpti_SubscriberHandle subscriber)

  Enable or disable all callbacks in all domains.

CUptiResult cuptiEnableCallback(uint32_t enable, CUpti_SubscriberHandle subscriber, CUpti_CallbackDomain domain, CUpti_CallbackId cbid)

  Enable or disabled callbacks for a specific domain and callback ID.

CUptiResult cuptiEnableDomain(uint32_t enable, CUpti_SubscriberHandle subscriber, CUpti_CallbackDomain domain)

  Enable or disabled all callbacks for a specific domain.

CUptiResult cuptiGetCallbackName(CUpti_CallbackDomain domain, uint32_t cbid, const char **name)

  Get the name of a callback for a specific domain and callback ID.

CUptiResult cuptiGetCallbackState(uint32_t *enable, CUpti_SubscriberHandle subscriber, CUpti_CallbackDomain domain, CUpti_CallbackId cbid)

  Get the current enabled/disabled state of a callback for a specific domain and function ID.

CUptiResult cuptiGetEnabledCallbacks(CUpti_SubscriberHandle subscriber, CUpti_CallbackDomain domain, CUpti_CallbackId *buffer, uint32_t *bufferSize, uint32_t *enabledCallbacksCount)

  Get the enabled callbacks for a subscriber.

CUptiResult cuptiSubscribe(CUpti_SubscriberHandle *subscriber, CUpti_CallbackFunc callback, void *userdata)

  Initialize a callback subscriber with a callback function and user data.

CUptiResult cuptiSubscribe_v2(CUpti_SubscriberHandle *subscriber, CUpti_CallbackFunc callback, void *userdata, CUpti_SubscriberParams *pParams)

  Initialize a callback subscriber with a callback function and user data.

CUptiResult cuptiSupportedDomains(size_t *domainCount, CUpti_DomainTable *domainTable)

  Get the available callback domains.

CUptiResult cuptiUnsubscribe(CUpti_SubscriberHandle subscriber)

  Unregister a callback subscriber.

## 6.2.5. Typedefs

CUpti_CallbackFunc

  Function type for a callback.

CUpti_CallbackId

  An ID for a driver API, runtime API, resource or synchronization callback.

CUpti_DomainTable

  Pointer to an array of callback domains.

CUpti_SubscriberHandle

  A callback subscriber.

## 6.2.6. Macros

CUPTI_CALLBACK_STRUCT_SIZE(type_, lastfield_)

CUPTI_OLD_SUBSCRIBER_NAME_MIN_LEN

  The minimum size of the of the old subscriber name in bytes.

CUPTI_SUBSCRIBER_NAME_MAX_LEN

  The max size of the CUPTI subscriber name in bytes.

  The total size of the CUPTI subscriber name is 64 bytes. CUPTI adds a 10 byte prefix and a null terminator, leaving 53 bytes for the user supplied subscriber name.

CUpti_SubscriberParams_STRUCT_SIZE

## 6.2.7. Enumerations

enum CUpti_ApiCallbackSite

  Specifies the point in an API call that a callback is issued.

  Specifies the point in an API call that a callback is issued. This value is communicated to the callback function via CUpti_CallbackData::callbackSite.

  Values:

  enumerator CUPTI_API_ENTER

    The callback is at the entry of the API call.

  enumerator CUPTI_API_EXIT

    The callback is at the exit of the API call.

  enumerator CUPTI_API_CBSITE_FORCE_INT

enum CUpti_CallbackDomain

  Callback domains.

  Callback domains. Each domain represents callback points for a group of related API functions or CUDA driver activity.

  Values:

  enumerator CUPTI_CB_DOMAIN_INVALID

    Invalid domain.

  enumerator CUPTI_CB_DOMAIN_DRIVER_API

    Domain containing callback points for all driver API functions.

  enumerator CUPTI_CB_DOMAIN_RUNTIME_API

    Domain containing callback points for all runtime API functions.

  enumerator CUPTI_CB_DOMAIN_RESOURCE

    Domain containing callback points for CUDA resource tracking.

  enumerator CUPTI_CB_DOMAIN_SYNCHRONIZE

    Domain containing callback points for CUDA synchronization.

  enumerator CUPTI_CB_DOMAIN_NVTX

    Domain containing callback points for NVTX API functions.

  enumerator CUPTI_CB_DOMAIN_STATE

    Domain containing callback points for various states.

  enumerator CUPTI_CB_DOMAIN_SIZE
  enumerator CUPTI_CB_DOMAIN_FORCE_INT

enum CUpti_CallbackIdResource

  Callback IDs for resource domain.

  Callback IDs for resource domain, CUPTI_CB_DOMAIN_RESOURCE. This value is communicated to the callback function via the `cbid` parameter.

  Values:

  enumerator CUPTI_CBID_RESOURCE_INVALID

    Invalid resource callback ID.

  enumerator CUPTI_CBID_RESOURCE_CONTEXT_CREATED

    A new context has been created.

  enumerator CUPTI_CBID_RESOURCE_CONTEXT_DESTROY_STARTING

    A context is about to be destroyed.

  enumerator CUPTI_CBID_RESOURCE_STREAM_CREATED

    A new stream has been created.

  enumerator CUPTI_CBID_RESOURCE_STREAM_DESTROY_STARTING

    A stream is about to be destroyed.

  enumerator CUPTI_CBID_RESOURCE_CU_INIT_FINISHED

    The driver has finished initializing.

  enumerator CUPTI_CBID_RESOURCE_MODULE_LOADED

    A module has been loaded.

  enumerator CUPTI_CBID_RESOURCE_MODULE_UNLOAD_STARTING

    A module is about to be unloaded.

  enumerator CUPTI_CBID_RESOURCE_MODULE_PROFILED

    The current module which is being profiled.

  enumerator CUPTI_CBID_RESOURCE_GRAPH_CREATED

    CUDA graph has been created.

  enumerator CUPTI_CBID_RESOURCE_GRAPH_DESTROY_STARTING

    CUDA graph is about to be destroyed.

  enumerator CUPTI_CBID_RESOURCE_GRAPH_CLONED

    CUDA graph is cloned.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_CREATE_STARTING

    CUDA graph node is about to be created.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_CREATED

    CUDA graph node is created.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_DESTROY_STARTING

    CUDA graph node is about to be destroyed.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_DEPENDENCY_CREATED

    Dependency on a CUDA graph node is created.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_DEPENDENCY_DESTROY_STARTING

    Dependency on a CUDA graph node is destroyed.

  enumerator CUPTI_CBID_RESOURCE_GRAPHEXEC_CREATE_STARTING

    An executable CUDA graph is about to be created.

  enumerator CUPTI_CBID_RESOURCE_GRAPHEXEC_CREATED

    An executable CUDA graph is created.

  enumerator CUPTI_CBID_RESOURCE_GRAPHEXEC_DESTROY_STARTING

    An executable CUDA graph is about to be destroyed.

  enumerator CUPTI_CBID_RESOURCE_GRAPHNODE_CLONED

    CUDA graph node is cloned.

  enumerator CUPTI_CBID_RESOURCE_STREAM_ATTRIBUTE_CHANGED

    CUDA stream attribute is changed.

  enumerator CUPTI_CBID_RESOURCE_GRAPH_NODE_UPDATED

    CUDA graph node is updated.

  enumerator CUPTI_CBID_RESOURCE_GRAPH_NODE_SET_PARAMS

    Params are set for the CUDA graph node in the executable graph.

  enumerator CUPTI_CBID_RESOURCE_SIZE
  enumerator CUPTI_CBID_RESOURCE_FORCE_INT

enum CUpti_CallbackIdState

  Callback IDs for state domain.

  Callback IDs for state domain, CUPTI_CB_DOMAIN_STATE. This value is communicated to the callback function via the `cbid` parameter.

  Values:

  enumerator CUPTI_CBID_STATE_INVALID

    Invalid state callback ID.

  enumerator CUPTI_CBID_STATE_FATAL_ERROR

    Notification of fatal errors - high impact, non-recoverable When encountered, CUPTI automatically invokes cuptiFinalize() User can control behavior of the application in future from receiving this callback - such as continuing without profiling, or terminating the whole application.

  enumerator CUPTI_CBID_STATE_ERROR

    Notification of non fatal errors - high impact, but recoverable This notification is not issued in the current release.

  enumerator CUPTI_CBID_STATE_WARNING

    Notification of warnings - low impact, recoverable.

  enumerator CUPTI_CBID_STATE_SIZE
  enumerator CUPTI_CBID_STATE_FORCE_INT

enum CUpti_CallbackIdSync

  Callback IDs for synchronization domain.

  Callback IDs for synchronization domain, CUPTI_CB_DOMAIN_SYNCHRONIZE. This value is communicated to the callback function via the `cbid` parameter.

  Values:

  enumerator CUPTI_CBID_SYNCHRONIZE_INVALID

    Invalid synchronize callback ID.

  enumerator CUPTI_CBID_SYNCHRONIZE_STREAM_SYNCHRONIZED

    Stream synchronization has completed for the stream.

  enumerator CUPTI_CBID_SYNCHRONIZE_CONTEXT_SYNCHRONIZED

    Context synchronization has completed for the context.

  enumerator CUPTI_CBID_SYNCHRONIZE_SIZE
  enumerator CUPTI_CBID_SYNCHRONIZE_FORCE_INT

## 6.2.8. Functions

CUptiResult cuptiEnableAllDomains(

  uint32_t enable,
  CUpti_SubscriberHandle subscriber,

)

  Enable or disable all callbacks in all domains.

  Enable or disable all callbacks in all domains.

  Note

  Thread-safety

  : a subscriber must serialize access to cuptiGetCallbackState, cuptiEnableCallback, cuptiEnableDomain, and cuptiEnableAllDomains. For example, if cuptiGetCallbackState(sub,

  d, *) and cuptiEnableAllDomains(sub) are called concurrently, the results are undefined.

  Parameters:

    - enable – New enable state for all callbacks in all domain. Zero disables all callbacks, non-zero enables all callbacks.

    - subscriber – - Handle to callback subscription

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialized CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `subscriber` is invalid

CUptiResult cuptiEnableCallback(

  uint32_t enable,
  CUpti_SubscriberHandle subscriber,
  CUpti_CallbackDomain domain,
  CUpti_CallbackId cbid,

)

  Enable or disabled callbacks for a specific domain and callback ID.

  Enable or disabled callbacks for a subscriber for a specific domain and callback ID.

  Note

  Thread-safety

  : a subscriber must serialize access to cuptiGetCallbackState, cuptiEnableCallback, cuptiEnableDomain, and cuptiEnableAllDomains. For example, if cuptiGetCallbackState(sub,

  d, c) and cuptiEnableCallback(sub, d, c) are called concurrently, the results are undefined.

  Parameters:

    - enable – New enable state for the callback. Zero disables the callback, non-zero enables the callback.

    - subscriber – - Handle to callback subscription

    - domain – The domain of the callback

    - cbid – The ID of the callback

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialized CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `subscriber`, `domain` or `cbid` is invalid.

CUptiResult cuptiEnableDomain(

  uint32_t enable,
  CUpti_SubscriberHandle subscriber,
  CUpti_CallbackDomain domain,

)

  Enable or disabled all callbacks for a specific domain.

  Enable or disabled all callbacks for a specific domain.

  Note

  Thread-safety

  : a subscriber must serialize access to cuptiGetCallbackState, cuptiEnableCallback, cuptiEnableDomain, and cuptiEnableAllDomains. For example, if cuptiGetCallbackEnabled(sub,

  d, *) and cuptiEnableDomain(sub, d) are called concurrently, the results are undefined.

  Parameters:

    - enable – New enable state for all callbacks in the domain. Zero disables all callbacks, non-zero enables all callbacks.

    - subscriber – - Handle to callback subscription

    - domain – The domain of the callback

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialized CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `subscriber` or `domain` is invalid

CUptiResult cuptiGetCallbackName(

  CUpti_CallbackDomain domain,
  uint32_t cbid,
  const char **name,

)

  Get the name of a callback for a specific domain and callback ID.

  Returns a pointer to the name c_string in `**name`.

  Note

  Names are available only for the DRIVER and RUNTIME domains.

  Parameters:

    - domain – The domain of the callback

    - cbid – The ID of the callback

    - name – Returns pointer to the name string on success, NULL otherwise

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_INVALID_PARAMETER – if `name` is NULL, or if `domain` or `cbid` is invalid.

CUptiResult cuptiGetCallbackState(

  uint32_t *enable,
  CUpti_SubscriberHandle subscriber,
  CUpti_CallbackDomain domain,
  CUpti_CallbackId cbid,

)

  Get the current enabled/disabled state of a callback for a specific domain and function ID.

  Returns non-zero in `*enable` if the callback for a domain and callback ID is enabled, and zero if not enabled.

  Note

  Thread-safety

  : a subscriber must serialize access to cuptiGetCallbackState, cuptiEnableCallback, cuptiEnableDomain, and cuptiEnableAllDomains. For example, if cuptiGetCallbackState(sub,

  d, c) and cuptiEnableCallback(sub, d, c) are called concurrently, the results are undefined.

  Parameters:

    - enable – Returns non-zero if callback enabled, zero if not enabled

    - subscriber – Handle to the initialize subscriber

    - domain – The domain of the callback

    - cbid – The ID of the callback

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialized CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `enabled` is NULL, or if `subscriber`, `domain` or `cbid` is invalid.

CUptiResult cuptiGetEnabledCallbacks(

  CUpti_SubscriberHandle subscriber,
  CUpti_CallbackDomain domain,
  CUpti_CallbackId *buffer,
  uint32_t *bufferSize,
  uint32_t *enabledCallbacksCount,

)

  Get the enabled callbacks for a subscriber.

  Note

  If the provided buffer size is not sufficient to store all the enabled callbacks, we populate the buffer with as much as we can, but return the true value of the number of enabled callbacks in `enabledCallbacksCount`.

  Parameters:

    - subscriber – The subscriber handle. If NULL, the union of callbacks (for that domain) enabled across all subscribers is returned.

    - domain – The domain of the callbacks to get. If NULL, CUPTI_ERROR_INVALID_PARAMETER is returned.

    - buffer – The buffer to store the enabled callbacks. If NULL, the number of enabled callbacks is returned in `enabledCallbacksCount`.

    - bufferSize – The size of the buffer. If NULL, only the number of enabled callbacks is returned in `enabledCallbacksCount`. If NULL and `buffer` is not NULL, CUPTI_ERROR_INVALID_PARAMETER is returned.

    - enabledCallbacksCount – The number of enabled callbacks. If NULL, CUPTI_ERROR_INVALID_PARAMETER is returned.

  Return values:

    - CUPTI_SUCCESS –

    - CUPTI_ERROR_INVALID_PARAMETER – if `enabledCallbacksCount` is NULL, or if `subscriber` or `domain` is invalid.

CUptiResult cuptiSubscribe(

  CUpti_SubscriberHandle *subscriber,
  CUpti_CallbackFunc callback,
  void *userdata,

)

  Initialize a callback subscriber with a callback function and user data.

  Initializes a callback subscriber with a callback function and (optionally) a pointer to user data. The returned subscriber handle can be used to enable and disable the callback for specific domains and callback IDs.

  Note

  Only a single subscriber can be registered at a time. To ensure that no other CUPTI client interrupts the profiling session, it’s the responsibility of all the CUPTI clients to call this function before starting the profling session. In case profiling session is already started by another CUPTI client, this function returns the error code CUPTI_ERROR_MULTIPLE_SUBSCRIBERS_NOT_SUPPORTED. Note that this function returns the same error when application is launched using NVIDIA tools like Nsight Systems, Nsight Compute, cuda-gdb and cuda-memcheck.

  Note

  This function does not enable any callbacks.

  Note

  Thread-safety: this function is thread safe.

  Note

  While this API is fully supported and remains available, we recommend transitioning to the new API cuptiSubscribe_v2 moving forward.

  Parameters:

    - subscriber – Returns handle to initialize subscriber

    - callback – The callback function

    - userdata – A pointer to user data. This data will be passed to the callback function via the `userdata` parameter.

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialize CUPTI

    - CUPTI_ERROR_MULTIPLE_SUBSCRIBERS_NOT_SUPPORTED – if there is already a CUPTI subscriber, or if the application is launched with NVIDIA tools like Nsight Systems, Nsight Compute, cuda-gdb and cuda-memcheck.

    - CUPTI_ERROR_INVALID_PARAMETER – if `subscriber` is NULL

CUptiResult cuptiSubscribe_v2(

  CUpti_SubscriberHandle *subscriber,
  CUpti_CallbackFunc callback,
  void *userdata,
  CUpti_SubscriberParams *pParams,

)

  Initialize a callback subscriber with a callback function and user data.

  Initializes a callback subscriber with a callback function and (optionally) a pointer to user data. The returned subscriber handle can be used to enable and disable the callback for specific domains and callback IDs.

  Note

  Only a single subscriber can be registered at a time. To ensure that no other CUPTI client interrupts the profiling session, it’s the responsibility of all the CUPTI clients to call this function before starting the profling session. In case profiling session is already started by another CUPTI client, this function returns the error code CUPTI_ERROR_MULTIPLE_SUBSCRIBERS_NOT_SUPPORTED. Note that this function returns the same error when application is launched using NVIDIA tools like Nsight Systems, Nsight Compute, cuda-gdb and cuda-memcheck.

  Note

  This function does not enable any callbacks.

  Note

  Thread-safety: this function is thread safe.

  Parameters:

    - subscriber – Returns handle to initialize subscriber

    - callback – The callback function

    - userdata – A pointer to user data. This data will be passed to the callback function via the `userdata` parameter.

    - pParams – A pointer to CUpti_SubscriberParams. Can be NULL.

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialize CUPTI

    - CUPTI_ERROR_MULTIPLE_SUBSCRIBERS_NOT_SUPPORTED – if there is already a CUPTI subscriber, or if the application is launched with NVIDIA tools like Nsight Systems, Nsight Compute, cuda-gdb and cuda-memcheck.

    - CUPTI_ERROR_INVALID_PARAMETER – if:

      - `pParams.structSize` is not filled with the size of the structure

CUptiResult cuptiSupportedDomains(

  size_t *domainCount,
  CUpti_DomainTable *domainTable,

)

  Get the available callback domains.

  Returns in `*domainTable` an array of size `*domainCount` of all the available callback domains.

  Note

  Thread-safety: this function is thread safe.

  Parameters:

    - domainCount – Returns number of callback domains

    - domainTable – Returns pointer to array of available callback domains

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialize CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `domainCount` or `domainTable` are NULL

CUptiResult cuptiUnsubscribe(CUpti_SubscriberHandle subscriber)

  Unregister a callback subscriber.

  Removes a callback subscriber so that no future callbacks will be issued to that subscriber.

  Note

  Thread-safety: this function is thread safe.

  Parameters:

    subscriber – Handle to the initialize subscriber

  Return values:

    - CUPTI_SUCCESS – on success

    - CUPTI_ERROR_NOT_INITIALIZED – if unable to initialized CUPTI

    - CUPTI_ERROR_INVALID_PARAMETER – if `subscriber` is NULL or not initialized

## 6.2.9. Typedefs

typedef void (*CUpti_CallbackFunc)(void *userdata, CUpti_CallbackDomain domain, CUpti_CallbackId cbid, const void *cbdata)

  Function type for a callback.

  Function type for a callback. The type of the data passed to the callback in `cbdata` depends on the `domain`. If `domain` is CUPTI_CB_DOMAIN_DRIVER_API or CUPTI_CB_DOMAIN_RUNTIME_API the type of `cbdata` will be CUpti_CallbackData. If `domain` is CUPTI_CB_DOMAIN_RESOURCE the type of `cbdata` will be CUpti_ResourceData. If `domain` is CUPTI_CB_DOMAIN_SYNCHRONIZE the type of `cbdata` will be CUpti_SynchronizeData. If `domain` is CUPTI_CB_DOMAIN_NVTX the type of `cbdata` will be CUpti_NvtxData.

  Param userdata:

    User data supplied at subscription of the callback

  Param domain:

    The domain of the callback

  Param cbid:

    The ID of the callback

  Param cbdata:

    Data passed to the callback.

typedef uint32_t CUpti_CallbackId

  An ID for a driver API, runtime API, resource or synchronization callback.

  An ID for a driver API, runtime API, resource or synchronization callback. Within a driver API callback this should be interpreted as a CUpti_driver_api_trace_cbid value (these values are defined in cupti_driver_cbid.h). Within a runtime API callback this should be interpreted as a CUpti_runtime_api_trace_cbid value (these values are defined in cupti_runtime_cbid.h). Within a resource API callback this should be interpreted as a CUpti_CallbackIdResource value. Within a synchronize API callback this should be interpreted as a CUpti_CallbackIdSync value.

typedef CUpti_CallbackDomain *CUpti_DomainTable

  Pointer to an array of callback domains.

typedef struct CUpti_Subscriber_st *CUpti_SubscriberHandle

  A callback subscriber.