HcclCommSymWinGet

Applicability

Function

Obtains the corresponding window resource handle and its offset within the window based on the virtual address pointer of the registered symmetric memory.

Prototype

1

HcclResult HcclCommSymWinGet(HcclComm comm, void *ptr, size_t size, HcclCommSymWindow *winHandle, size_t *offset)

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.

Call Example

// Create and initialize the configuration items of the communicator.
HcclCommConfig config;
HcclCommConfigInit(&config);
// Modify the communicator configuration as required.
config.hcclSymWinMaxMemSizePerRank = 10; // The default value is 16, in GB.

// Obtain the communicator parameters.
uint32_t rankSize = 4;
uint32_t rankId = 0;
int32_t deviceId;
ACLCHECK(aclrtGetDevice(&deviceId));
HcclRootInfo rootInfo;
HCCLCHECK(HcclGetRootInfo(&rootInfo));

// Initialize the collective communicator.
HcclComm hcclComm;
HCCLCHECK(HcclCommInitRootInfoConfig(rankSize, &rootInfo, rankId, &config, &hcclComm));

// Create a task flow.
aclrtStream stream;
ACLCHECK(aclrtCreateStream(&stream));

// Configure the physical memory attributes.
aclrtPhysicalMemProp prop;
prop.handleType = ACL_MEM_HANDLE_TYPE_NONE;
prop.allocationType = ACL_MEM_ALLOCATION_TYPE_PINNED;
prop.memAttr = ACL_HBM_MEM_HUGE;
prop.location.id = deviceId;
prop.location.type = ACL_MEM_LOCATION_TYPE_DEVICE;
prop.reserve = 0;

// Obtain the alignment granularity, which is usually 2 MB.
size_t granularity;
ACLCHECK(aclrtMemGetAllocationGranularity(&prop, ACL_RT_MEM_ALLOC_GRANULARITY_RECOMMENDED, &granularity));

// Align the size based on the granularity.
size_t size = 2 * 1024 * 1024;
size_t allocSize = (size + granularity - 1) / granularity * granularity;

// Reserve virtual memory.
void *virPtr;
ACLCHECK(aclrtReserveMemAddress(&virPtr, allocSize, 0, nullptr, 1));

// Allocate physical memory.
aclrtDrvMemHandle memHandle;
ACLCHECK(aclrtMallocPhysical(&memHandle, allocSize, &prop, 0));

// Establish the mapping from physical memory to virtual memory.
ACLCHECK(aclrtMapMem(virPtr, allocSize, 0, memHandle, 0));

HcclCommSymWindow symWin;
// Register symmetric memory.
HCCLCHECK(HcclCommSymWinRegister(hcclComm, virPtr, allocSize, &symWin, 1));

// Use HcclCommSymWinGet to obtain symmetric memory resources.
HcclCommSymWindow tempWin;
size_t offset = 0;
HCCLCHECK(HcclCommSymWinGet(hcclComm, virPtr, allocSize, &tempWin, &offset));

// Deregister symmetric memory.
HCCLCHECK(HcclCommSymWinDeregister(symWin));

// Free memory.
ACLCHECK(aclrtUnmapMem(virPtr));
ACLCHECK(aclrtFreePhysical(memHandle));
ACLCHECK(aclrtReleaseMemAddress(virPtr));

 // Destroy the task flow.
ACLCHECK(aclrtDestroyStream(stream));

// Destroy the communicator.
HCCLCHECK(HcclCommDestroy(hcclComm));