Stream management

Stream management#

typedef void (*hipStreamCallback_t)(hipStream_t stream, hipError_t status, void *userData)#: Stream CallBack struct

hipError_t hipStreamCreate(hipStream_t *stream)#

Create an asynchronous stream.

Create a new asynchronous stream. stream returns an opaque handle that can be used to reference the newly created stream in subsequent hipStream* commands. The stream is allocated on the heap and will remain allocated even if the handle goes out-of-scope. To release the memory used by the stream, application must call hipStreamDestroy.

Parameters:: stream – [inout] Valid pointer to hipStream_t. This function writes the memory with the newly created stream.
Returns:: hipSuccess, hipErrorInvalidValue
Returns:: hipSuccess, hipErrorInvalidValue

hipError_t hipStreamCreateWithFlags(hipStream_t *stream, unsigned int flags)#

Create an asynchronous stream.

Create a new asynchronous stream. stream returns an opaque handle that can be used to reference the newly created stream in subsequent hipStream* commands. The stream is allocated on the heap and will remain allocated even if the handle goes out-of-scope. To release the memory used by the stream, application must call hipStreamDestroy. Flags controls behavior of the stream. See hipStreamDefault, hipStreamNonBlocking.

Parameters:

stream – [inout] Pointer to new stream
flags – [in] to control stream creation.

Returns:

hipSuccess, hipErrorInvalidValue

hipError_t hipStreamCreateWithPriority(hipStream_t *stream, unsigned int flags, int priority)#

Create an asynchronous stream with the specified priority.

Create a new asynchronous stream with the specified priority. stream returns an opaque handle that can be used to reference the newly created stream in subsequent hipStream* commands. The stream is allocated on the heap and will remain allocated even if the handle goes out-of-scope. To release the memory used by the stream, application must call hipStreamDestroy. Flags controls behavior of the stream. See hipStreamDefault, hipStreamNonBlocking.

Parameters:

stream – [inout] Pointer to new stream
flags – [in] to control stream creation.
priority – [in] of the stream. Lower numbers represent higher priorities.

Returns:

hipSuccess, hipErrorInvalidValue

hipError_t hipDeviceGetStreamPriorityRange(int *leastPriority, int *greatestPriority)#

Returns numerical values that correspond to the least and greatest stream priority.

Returns in *leastPriority and *greatestPriority the numerical values that correspond to the least and greatest stream priority respectively. Stream priorities follow a convention where lower numbers imply greater priorities. The range of meaningful stream priorities is given by [*greatestPriority, *leastPriority]. If the user attempts to create a stream with a priority value that is outside the meaningful range as specified by this API, the priority is automatically clamped to within the valid range.

Parameters:

leastPriority – [inout] pointer in which value corresponding to least priority is returned.
greatestPriority – [inout] pointer in which value corresponding to greatest priority is returned.

Returns:

hipSuccess

hipError_t hipStreamDestroy(hipStream_t stream)#

Destroys the specified stream.

If commands are still executing on the specified stream, some may complete execution before the queue is deleted.

The queue may be destroyed while some commands are still inflight, or may wait for all commands queued to the stream before destroying it.

Parameters:: stream – [in] stream identifier.
Returns:: hipSuccess hipErrorInvalidHandle

hipError_t hipStreamQuery(hipStream_t stream)#

Return hipSuccess if all of the operations in the specified stream have completed, or hipErrorNotReady if not.

This is thread-safe and returns a snapshot of the current state of the queue. However, if other host threads are sending work to the stream, the status may change immediately after the function is called. It is typically used for debug.

Parameters:: stream – [in] stream to query
Returns:: hipSuccess, hipErrorNotReady, hipErrorInvalidHandle

hipError_t hipStreamSynchronize(hipStream_t stream)#

Wait for all commands in stream to complete.

This command is host-synchronous : the host will block until the specified stream is empty.

This command follows standard null-stream semantics. Specifically, specifying the null stream will cause the command to wait for other streams on the same device to complete all pending operations.

This command honors the hipDeviceLaunchBlocking flag, which controls whether the wait is active or blocking.

Parameters:: stream – [in] stream identifier.
Returns:: hipSuccess, hipErrorInvalidHandle

hipError_t hipStreamWaitEvent(hipStream_t stream, hipEvent_t event, unsigned int flags)#

Make the specified compute stream wait for an event.

This function inserts a wait operation into the specified stream. All future work submitted to stream will wait until event reports completion before beginning execution.

This function only waits for commands in the current stream to complete. Notably, this function does not implicitly wait for commands in the default stream to complete, even if the specified stream is created with hipStreamNonBlocking = 0.

Parameters:

stream – [in] stream to make wait.
event – [in] event to wait on
flags – [in] control operation [must be 0]

Returns:

hipSuccess, hipErrorInvalidHandle

hipError_t hipStreamGetFlags(hipStream_t stream, unsigned int *flags)#

Return flags associated with this stream.

Return flags associated with this stream in *flags.

See also

hipStreamCreateWithFlags

Parameters:

stream – [in] stream to be queried
flags – [inout] Pointer to an unsigned integer in which the stream’s flags are returned

Returns:

hipSuccess, hipErrorInvalidValue, hipErrorInvalidHandle

Returns:

hipSuccess hipErrorInvalidValue hipErrorInvalidHandle

hipError_t hipStreamGetPriority(hipStream_t stream, int *priority)#

Query the priority of a stream.

Query the priority of a stream. The priority is returned in in priority.

See also

hipStreamCreateWithFlags

Parameters:

stream – [in] stream to be queried
priority – [inout] Pointer to an unsigned integer in which the stream’s priority is returned

Returns:

hipSuccess, hipErrorInvalidValue, hipErrorInvalidHandle

Returns:

hipSuccess hipErrorInvalidValue hipErrorInvalidHandle

hipError_t hipStreamGetDevice(hipStream_t stream, hipDevice_t *device)#

Get the device assocaited with the stream.

Parameters:

stream – [in] stream to be queried
device – [out] device associated with the stream

Returns:

hipSuccess, hipErrorInvalidValue, hipErrorContextIsDestroyed, hipErrorInvalidHandle, hipErrorNotInitialized, hipErrorDeinitialized, hipErrorInvalidContext

hipError_t hipExtStreamCreateWithCUMask(hipStream_t *stream, uint32_t cuMaskSize, const uint32_t *cuMask)#

Create an asynchronous stream with the specified CU mask.

Create a new asynchronous stream with the specified CU mask. stream returns an opaque handle that can be used to reference the newly created stream in subsequent hipStream* commands. The stream is allocated on the heap and will remain allocated even if the handle goes out-of-scope. To release the memory used by the stream, application must call hipStreamDestroy.

Parameters:

stream – [inout] Pointer to new stream
cuMaskSize – [in] Size of CU mask bit array passed in.
cuMask – [in] Bit-vector representing the CU mask. Each active bit represents using one CU. The first 32 bits represent the first 32 CUs, and so on. If its size is greater than physical CU number (i.e., multiProcessorCount member of hipDeviceProp_t), the extra elements are ignored. It is user’s responsibility to make sure the input is meaningful.

Returns:

hipSuccess, hipErrorInvalidHandle, hipErrorInvalidValue

hipError_t hipExtStreamGetCUMask(hipStream_t stream, uint32_t cuMaskSize, uint32_t *cuMask)#

Get CU mask associated with an asynchronous stream.

Parameters:

stream – [in] stream to be queried
cuMaskSize – [in] number of the block of memories (uint32_t *) allocated by user
cuMask – [out] Pointer to a pre-allocated block of memories (uint32_t *) in which the stream’s CU mask is returned. The CU mask is returned in a chunck of 32 bits where each active bit represents one active CU

Returns:

hipSuccess, hipErrorInvalidHandle, hipErrorInvalidValue

hipError_t hipStreamAddCallback(hipStream_t stream, hipStreamCallback_t callback, void *userData, unsigned int flags)#

Adds a callback to be called on the host after all currently enqueued items in the stream have completed. For each hipStreamAddCallback call, a callback will be executed exactly once. The callback will block later work in the stream until it is finished.

Parameters:

stream – [in] - Stream to add callback to
callback – [in] - The function to call once preceding stream operations are complete
userData – [in] - User specified data to be passed to the callback function
flags – [in] - Reserved for future use, must be 0

Returns:

hipSuccess, hipErrorInvalidHandle, hipErrorNotSupported

Stream management

Contents

Stream management#