0_ipcevent

Description

This sample demonstrates task synchronization between two processes using IPC Event.

• Process A (producer): Creates IPC event, records event and exports handle, then waits for consumer to complete.
• Process B (consumer): Imports IPC event handle, waits for event, completes work then records event to notify producer.

This sample uses binary file to pass event handle, demonstrating core IPC event usage: create, export, import, wait, record, query, and destroy.

Product Support

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

Build and Run

This sample launches proc_a and proc_b processes simultaneously by run.sh, and exchanges IPC Event handle through temporary file. For environment installation details and general running steps, see README in the example directory.

Run steps:

# Replace ${install_root} with CANN installation root directory, default installation at /usr/local/Ascend
source ${install_root}/cann/set_env.sh

# Automatically identify SOC_VERSION and ASCENDC_CMAKE_DIR.
source ${git_clone_path}/example/set_sample_env.sh

# Build and run
bash run.sh

CANN RUNTIME API

Key features and interfaces in this sample:

• Initialization

  • Call aclInit interface to initialize configuration.
  • Call aclFinalize interface to deinitialize.

• Device Management

  • Call aclrtSetDevice interface to specify Device for computation.
  • Call aclrtResetDevice interface to reset Device.

  Note: This sample is a multi-process IPC scenario on one host. Each process calls aclrtResetDevice when it exits to release its own Device resources, avoiding the forced reset effect of aclrtResetDeviceForce on other processes on the same host.

• Stream Management

  • Call aclrtCreateStream interface to create Stream.
  • Call aclrtSynchronizeStream interface to block waiting for Stream task completion.
  • Call aclrtDestroyStream interface to destroy Stream.

• Event Management

  • Call aclrtCreateEventExWithFlag interface to create IPC-enabled Event.
  • Call aclrtRecordEvent interface to record Event.
  • Call aclrtSynchronizeEvent interface to block waiting for Event completion.
  • Call aclrtQueryEventStatus interface to query Event status.
  • Call aclrtIpcGetEventHandle interface to get Event IPC handle.
  • Call aclrtIpcOpenEventHandle interface to open IPC Event.
  • Call aclrtStreamWaitEvent interface to block Stream waiting for Event completion.
  • Call aclrtDestroyEvent interface to destroy Event.

Sample Output

[INFO]  Process A: IPC event created
[INFO]  Process A: event recorded and synchronized
[INFO]  Process A: event status = 1 (1=completed)
[INFO]  Process A: IPC event handle written to ./event_handle.bin
[INFO]  Process A: consumer finished
[INFO]  Process A: cleanup completed
[INFO]  Process B: IPC event opened
[INFO]  Process B: event received, stream synchronized
[INFO]  Process B: event status = 1 (1=completed)
[INFO]  Process B: cleanup completed
[SUCCESS] IPC event synchronization works correctly.