aclrtSubscribeReport

Product	Supported
Ascend 950PR / Ascend 950DT	√
Atlas A3 training products / Atlas A3 inference products	√
Atlas A2 training products / Atlas A2 inference products	√
Atlas 200I/500 A2 inference products	√
Atlas inference products	√
Atlas training products	√

Subscribes to a thread for handling the callback function in a stream.

This API must be work with the following APIs to implement the callback function in asynchronous scenarios:

Define and implement a callback function. Function prototype: typedef void (*aclrtCallback)(void *userData)
Create a thread. Call aclrtProcessReport in the thread function to set the timeout interval (cyclic calling is required), and wait for the callback task execution.
Call aclrtSubscribeReport to bind the thread created in Step 2 to the stream. The callback function delivered by the stream is executed in the bound thread.
Execute an asynchronous task (for example, an asynchronous inference job) on the specified stream.
Call aclrtLaunchCallback to deliver a callback task in the task queue of the stream and trigger the thread created in step 2 to process the callback function. Each time aclrtLaunchCallback is called, the callback function is executed.
After all asynchronous tasks are executed, call aclrtUnSubscribeReport to unsubscribe from the thread.

      
           aclError aclrtSubscribeReport(uint64_t threadId, aclrtStream stream)

Parameter	Input/Output	Description
threadId	Input	Thread ID.
stream	Input	Stream. For details about the type definition, see aclrtStream.

0 on success; otherwise, failure. For details, see aclError.

Calling aclrtSubscribeReport multiple times to register the same callback thread for multiple streams is supported (restricted to multiple streams within the same device). To ensure that tasks within a stream are executed in the order of invocation, registering multiple callback threads for a single stream via aclrtSubscribeReport is not supported. Within the same process, the same thread ID cannot be specified when registering callback threads across different devices.
If the number of threads subscribed by this call in a single process exceeds a specified limit, a failure code is returned. Considering the thread switching performance overhead of the OS, try to keep the number of threads subscribed by the aclrtSubscribeReport call within 32. Currently, a maximum of 1,024 threads are supported.

For details about the API call sequence and sample code, see Asynchronous Model Inference.

Parent topic: Execution Control