Function: memcpy_async

Applicability

Product	Supported
Atlas 350 Accelerator Card	√
Atlas A3 training product/Atlas A3 inference product	√
Atlas A2 training product/Atlas A2 inference product	√
Atlas training product	√
Atlas inference product	√
Atlas 200I/500 A2 inference product	√

Description

Copies memory. This API is asynchronous.

The host memory in this API supports lock page memory (for example, the memory allocated by using the acl.rt.malloc_host API) and non-lock page memory (for example, the memory allocated by using the malloc API). If the host memory is not a lock page memory, this API is returned only after the memory copy task is complete. When the host memory is the lock page memory, this API is an asynchronous API. If the API is successfully called, the task is successfully delivered but not executed. After this API is called, the synchronous waiting API (for example, acl.rt.synchronize_stream) needs to be called to ensure that the memory replication task is complete.

Prototype

C Prototype

aclError aclrtMemcpyAsync(void *dst, size_t destMax, const void *src, size_t count, aclrtMemcpyKind kind, aclrtStream stream)

Python Function

ret = acl.rt.memcpy_async(dst, dest_max, src, count, kind, stream)

Parameters

Parameter	Description
dst	Int, pointer address of the destination memory address.
dest_max	Int, memory size in bytes in the destination address
src	Int, pointer address of the source memory address.
count	Int, size in bytes to copy.
kind	Int, memory copy type. ACL_MEMCPY_HOST_TO_HOST = 0 // Copy memory within the host. ACL_MEMCPY_HOST_TO_DEVICE = 1 // Copy memory from the host to the device. ACL_MEMCPY_DEVICE_TO_HOST = 2 // Copy memory from the device to the host. ACL_MEMCPY_DEVICE_TO_DEVICE = 3 // Copy memory within a device. 4: ACL_MEMCPY_DEFAULT. The system determines the copy direction based on the source and destination memory addresses.
stream	Int, stream ID.

Return Value

Return Value	Description
ret	Int, error code. 0 on success; else, failure.

Restrictions

The source address and destination address passed to this call must be 64-byte aligned.

Atlas inference product

Ascend EP: This API does not support asynchronous memory copy within the host. If the input kind is ACL_MEMCPY_HOST_TO_HOST, the API returns the error message " ACL_ERROR_RT_FEATURE_NOT_SUPPORT."

Atlas 200I/500 A2 inference product

Ascend EP: This API does not support asynchronous memory copy within the host. If the input kind is ACL_MEMCPY_HOST_TO_HOST, the API returns the error message " ACL_ERROR_RT_FEATURE_NOT_SUPPORT."
Ascend RC: When the application is running on the board, if the input kind is ACL_MEMCPY_HOST_TO_DEVICE, ACL_MEMCPY_DEVICE_TO_HOST, or ACL_MEMCPY_HOST_TO_HOST, the system uses ACL_MEMCPY_DEVICE_TO_DEVICE by default to copy memory within the device.

Atlas training product, Atlas A2 training product/Atlas A2 inference product, Atlas A3 training product/Atlas A3 inference product:

This API does not support asynchronous memory copy within the host. If the input kind is ACL_MEMCPY_HOST_TO_HOST, the API returns the error message "ACL_ERROR_RT_FEATURE_NOT_SUPPORT".

Parent topic: Memory Management