0_simple_stream

Description

This sample demonstrates single Stream task dispatch flow, including dispatching tasks on default Stream, dispatching tasks on newly created Stream, and querying Stream status after multiple task dispatches on the same Stream.

Product Support

This sample supports the following products:

Product	Supported
Ascend 950PR/Ascend 950DT	Yes
Atlas A3 training series products/Atlas A3 inference series products	Yes
Atlas A2 training series products/Atlas A2 inference series products	Yes

Compile and Run

1. Download the sample code to the environment where CANN software is installed. Switch to the sample directory.

cd ${git_clone_path}/example/1_basic_features/stream/0_simple_stream

2. Set environment variables.

# Replace ${install_root} with the CANN installation root directory. The default installation is in the `/usr/local/Ascend` directory.
source ${install_root}/cann/set_env.sh

# Set SOC_VERSION and ASCENDC_CMAKE_DIR
# -SOC_VERSION: Ascend AI processor model, such as Ascend910_9362, Ascend910B2, and so on
# -ASCENDC_CMAKE_DIR: The sample involves calling AscendC operators. Configure the AscendC compiler ascendc.cmake path, such as /usr/local/Ascend/cann/x86_64-linux/tikcpp/ascendc_kernel_cmake
source ${git_clone_path}/example/set_sample_env.sh

3. Run the following command to execute the sample.

bash run.sh

CANN RUNTIME API

The key functionality points and their key interfaces involved in this sample are as follows:

• Initialization
  • Call aclInit interface for initialization configuration.
  • Call aclFinalize interface for deinitialization.
• Device Management
  • Call aclrtSetDevice interface to specify the Device for computation.
  • Call aclrtResetDeviceForce interface to forcefully reset the current computation Device and reclaim Device resources.
• Context Management
  • Call aclrtCreateContext interface to create Context.
  • Call aclrtDestroyContext interface to destroy Context.
• Stream Management
  • Call aclrtCreateStream interface to create Stream.
  • Call aclrtSynchronizeStream interface to block and wait for Stream tasks to complete.
  • Call aclrtSetStreamFailureMode interface to set the operation when Stream execution encounters errors. Default is continue on error, can be set to stop on error.
  • Call aclrtStreamQuery interface to get Stream completion status.
  • Call aclrtDestroyStreamForce interface to forcefully destroy Stream and discard all tasks.
• Memory Management
  • Call aclrtMalloc interface to allocate memory on Device.
  • Call aclrtFree interface to release memory on Device.
• Data Transfer
  • Call aclrtMemcpy interface to implement data transfer through memory copy.

Sample Output

[INFO]  Use default stream assigning task.
[INFO]  Applied resource successfully, begin assigning task.
[INFO]  After assigning the task through the default stream, the current result is: 1.
[INFO]  Use created stream assigning task.
[INFO]  After assigning the task through the created stream, the current result is: 2.
[INFO]  Begin 3000 task.
[INFO]  After synchronize, stream status is: 0.
[INFO]  After loop, the current result is: 3002.
[INFO]  Resource cleanup completed.