HcclSymWinGetPeerPointer

Applicability

Function

Obtains the virtual address pointer on the symmetric memory for a rank ID, based on the symmetric memory window handle and offset.

Prototype

1

HcclResult HcclSymWinGetPeerPointer(HcclCommSymWindow winHandle, size_t offset, uint32_t peerRank, void** ptr)

Parameters

Returns

HcclResult: HCCL_SUCCESS on success, or else failure.

Constraints

• Only intra-SuperPoD communication of the Atlas A3 training product/Atlas A3 inference product is supported.
• The communication operator can be expanded only on AICPU.
• This API can be called only on the device side.

Call Example

After the symmetric memory window is registered on the host, the window is passed to the AICPU kernel as a parameter. This function needs to be compiled and executed on the device AICPU. The following is the pseudocode:

AicpuKernelFunc(param):
// Obtain the symmetric window from param.
HcclCommSymWindow temp_win = param.win;
void *src_ptr;
void *dest_ptr;
int srcRankId = 0;
int destRankId = 1;
// Use win + offset + peerRank to obtain the address corresponding to peerRank.
HcclSymWinGetPeerPointer(temp_win, 0, srcRankId, &src_ptr);
HcclSymWinGetPeerPointer(temp_win, 0, destRankId, &dest_ptr);
// The obtained address can be directly read and written using the local copy on the data plane. The thread and size need to be prepared by the caller.
HcommLocalCopyOnThread(thread, dest_ptr, src_ptr, size);