Stream Management#

HIP Runtime API Reference: Stream Management
Stream Management

This section describes the stream management functions of HIP runtime API. The following Stream APIs are not (yet) supported in HIP: More...

Collaboration diagram for Stream Management:

Typedefs

typedef void(* hipStreamCallback_t) (hipStream_t stream, hipError_t status, void *userData)
 

Functions

hipError_t hipStreamCreate (hipStream_t *stream)
 Create an asynchronous stream. More...
 
hipError_t hipStreamCreateWithFlags (hipStream_t *stream, unsigned int flags)
 Create an asynchronous stream. More...
 
hipError_t hipStreamCreateWithPriority (hipStream_t *stream, unsigned int flags, int priority)
 Create an asynchronous stream with the specified priority. More...
 
hipError_t hipDeviceGetStreamPriorityRange (int *leastPriority, int *greatestPriority)
 Returns numerical values that correspond to the least and greatest stream priority. More...
 
hipError_t hipStreamDestroy (hipStream_t stream)
 Destroys the specified stream. More...
 
hipError_t hipStreamQuery (hipStream_t stream)
 Return hipSuccess if all of the operations in the specified stream have completed, or hipErrorNotReady if not. More...
 
hipError_t hipStreamSynchronize (hipStream_t stream)
 Wait for all commands in stream to complete. More...
 
hipError_t hipStreamWaitEvent (hipStream_t stream, hipEvent_t event, unsigned int flags)
 Make the specified compute stream wait for an event. More...
 
hipError_t hipStreamGetFlags (hipStream_t stream, unsigned int *flags)
 Return flags associated with this stream. More...
 
hipError_t hipStreamGetPriority (hipStream_t stream, int *priority)
 Query the priority of a stream. More...
 
hipError_t hipExtStreamCreateWithCUMask (hipStream_t *stream, uint32_t cuMaskSize, const uint32_t *cuMask)
 Create an asynchronous stream with the specified CU mask. More...
 
hipError_t hipExtStreamGetCUMask (hipStream_t stream, uint32_t cuMaskSize, uint32_t *cuMask)
 Get CU mask associated with an asynchronous stream. More...
 
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. More...
 

Detailed Description

This section describes the stream management functions of HIP runtime API. The following Stream APIs are not (yet) supported in HIP:



  • hipStreamAttachMemAsync is a nop

Typedef Documentation

◆ hipStreamCallback_t

typedef void(* hipStreamCallback_t) (hipStream_t stream, hipError_t status, void *userData)

Stream CallBack struct

Function Documentation

◆ hipDeviceGetStreamPriorityRange()

hipError_t hipDeviceGetStreamPriorityRange ( int *  leastPriority,
int *  greatestPriority 
)

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

Parameters
[in,out]leastPrioritypointer in which value corresponding to least priority is returned.
[in,out]greatestPrioritypointer in which value corresponding to greatest priority is returned.

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 the meaningful range as specified by this API, the priority is automatically clamped to within the valid range.

◆ hipExtStreamCreateWithCUMask()

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

Create an asynchronous stream with the specified CU mask.

Parameters
[in,out]streamPointer to new stream
[in]cuMaskSizeSize of CU mask bit array passed in.
[in]cuMaskBit-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

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.

See also
hipStreamCreate, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy

◆ hipExtStreamGetCUMask()

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

Get CU mask associated with an asynchronous stream.

Parameters
[in]streamstream to be queried
[in]cuMaskSizenumber of the block of memories (uint32_t *) allocated by user
[out]cuMaskPointer 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
See also
hipStreamCreate, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy

◆ hipStreamAddCallback()

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
[in]stream- Stream to add callback to
[in]callback- The function to call once preceding stream operations are complete
[in]userData- User specified data to be passed to the callback function
[in]flags- Reserved for future use, must be 0
Returns
hipSuccess, hipErrorInvalidHandle, hipErrorNotSupported
See also
hipStreamCreate, hipStreamCreateWithFlags, hipStreamQuery, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy, hipStreamCreateWithPriority

◆ hipStreamCreate()

hipError_t hipStreamCreate ( hipStream_t stream)

Create an asynchronous stream.

Parameters
[in,out]streamValid pointer to hipStream_t. This function writes the memory with the newly created stream.
Returns
hipSuccess, hipErrorInvalidValue

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, applicaiton must call hipStreamDestroy.

Returns
hipSuccess, hipErrorInvalidValue
See also
hipStreamCreateWithFlags, hipStreamCreateWithPriority, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy

◆ hipStreamCreateWithFlags()

hipError_t hipStreamCreateWithFlags ( hipStream_t stream,
unsigned int  flags 
)

Create an asynchronous stream.

Parameters
[in,out]streamPointer to new stream
[in]flagsto control stream creation.
Returns
hipSuccess, hipErrorInvalidValue

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, applicaiton must call hipStreamDestroy. Flags controls behavior of the stream. See hipStreamDefault, hipStreamNonBlocking.

See also
hipStreamCreate, hipStreamCreateWithPriority, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy

◆ hipStreamCreateWithPriority()

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

Create an asynchronous stream with the specified priority.

Parameters
[in,out]streamPointer to new stream
[in]flagsto control stream creation.
[in]priorityof the stream. Lower numbers represent higher priorities.
Returns
hipSuccess, hipErrorInvalidValue

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, applicaiton must call hipStreamDestroy. Flags controls behavior of the stream. See hipStreamDefault, hipStreamNonBlocking.

See also
hipStreamCreate, hipStreamSynchronize, hipStreamWaitEvent, hipStreamDestroy

◆ hipStreamDestroy()

hipError_t hipStreamDestroy ( hipStream_t  stream)

Destroys the specified stream.

Parameters
[in,out]streamValid pointer to hipStream_t. This function writes the memory with the newly created stream.
Returns
hipSuccess hipErrorInvalidHandle

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.

See also
hipStreamCreate, hipStreamCreateWithFlags, hipStreamCreateWithPriority, hipStreamQuery, hipStreamWaitEvent, hipStreamSynchronize

◆ hipStreamGetFlags()

hipError_t hipStreamGetFlags ( hipStream_t  stream,
unsigned int *  flags 
)

Return flags associated with this stream.

Parameters
[in]streamstream to be queried
[in,out]flagsPointer to an unsigned integer in which the stream's flags are returned
Returns
hipSuccess, hipErrorInvalidValue, hipErrorInvalidHandle
hipSuccess hipErrorInvalidValue hipErrorInvalidHandle

Return flags associated with this stream in *flags.

See also
hipStreamCreateWithFlags

◆ hipStreamGetPriority()

hipError_t hipStreamGetPriority ( hipStream_t  stream,
int *  priority 
)

Query the priority of a stream.

Parameters
[in]streamstream to be queried
[in,out]priorityPointer to an unsigned integer in which the stream's priority is returned
Returns
hipSuccess, hipErrorInvalidValue, hipErrorInvalidHandle
hipSuccess hipErrorInvalidValue hipErrorInvalidHandle

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

See also
hipStreamCreateWithFlags

◆ hipStreamQuery()

hipError_t hipStreamQuery ( hipStream_t  stream)

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

Parameters
[in]streamstream to query
Returns
hipSuccess, hipErrorNotReady, hipErrorInvalidHandle

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.

See also
hipStreamCreate, hipStreamCreateWithFlags, hipStreamCreateWithPriority, hipStreamWaitEvent, hipStreamSynchronize, hipStreamDestroy

◆ hipStreamSynchronize()

hipError_t hipStreamSynchronize ( hipStream_t  stream)

Wait for all commands in stream to complete.

Parameters
[in]streamstream identifier.
Returns
hipSuccess, hipErrorInvalidHandle

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.

See also
hipStreamCreate, hipStreamCreateWithFlags, hipStreamCreateWithPriority, hipStreamWaitEvent, hipStreamDestroy

◆ hipStreamWaitEvent()

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

Make the specified compute stream wait for an event.

Parameters
[in]streamstream to make wait.
[in]eventevent to wait on
[in]flagscontrol operation [must be 0]
Returns
hipSuccess, hipErrorInvalidHandle

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 impliciy wait for commands in the default stream to complete, even if the specified stream is created with hipStreamNonBlocking = 0.

See also
hipStreamCreate, hipStreamCreateWithFlags, hipStreamCreateWithPriority, hipStreamSynchronize, hipStreamDestroy