e11238b302
Add new API for creating a reduction operation which multiplies the input by a rank-specific scalar before doing an inter-rank summation (see: ncclRedOpCreatePreMulSum). Improve CollNet (SHARP) performance of ncclAllReduce when captured in a CUDA Graph via user buffer registration. Add environment variable NCCL_NET_PLUGIN="<suffix>" to allow user to choose among multiple NCCL net plugins by substituting into "libnccl-net-<suffix>.so". Fix memory leak of NVB connections. Fix topology detection of IB Virtual Functions (SR-IOV).
337 lines
13 KiB
C++
337 lines
13 KiB
C++
/*************************************************************************
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* Copyright (c) 2016-2021, NVIDIA CORPORATION. All rights reserved.
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*
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* See LICENSE.txt for license information
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************************************************************************/
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#include "comm.h"
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#include "graph.h"
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#include "utils.h"
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#include "bootstrap.h"
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struct p2pConnectInfo {
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int rank;
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int read;
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void* directPtr;
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cudaIpcMemHandle_t devIpc;
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};
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struct p2pSendResources {
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struct ncclSendMem* devMem;
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void* ipcPtr;
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int remoteId;
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int memRank;
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void* remIpcPtr;
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void* bootstrap;
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};
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struct p2pRecvResources {
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struct ncclRecvMem* devMem;
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void* ipcPtr;
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int remoteId;
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int memRank;
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void* remIpcPtr;
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void* bootstrap;
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};
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#include <sys/types.h>
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/* Convert a PCI busId string into a local cudaDev device index (cf. CUDA_VISIBLE_DEVICES) */
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static int busIdToCudaDev(int64_t busId) {
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int ndev;
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if (cudaGetDeviceCount(&ndev) != cudaSuccess)
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return -1;
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for (int i = 0; i < ndev; i++) {
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char devBusIdStr[NVML_DEVICE_PCI_BUS_ID_BUFFER_SIZE];
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if (cudaDeviceGetPCIBusId(devBusIdStr, NVML_DEVICE_PCI_BUS_ID_BUFFER_SIZE, i) != cudaSuccess)
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return -1;
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int64_t devBusId;
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NCCLCHECK(busIdToInt64(devBusIdStr, &devBusId));
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if (busId == devBusId) return i;
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}
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// BusId was not found in our locally visible CUDA devices
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return -1;
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}
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/* Determine if two peers can communicate through p2p */
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ncclResult_t p2pCanConnect(int* ret, struct ncclTopoSystem* topo, struct ncclTopoGraph* graph, struct ncclPeerInfo* info1, struct ncclPeerInfo* info2) {
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// Rule out different nodes / isolated containers
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if (info1->hostHash != info2->hostHash || info1->shmDev != info2->shmDev) {
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*ret = 0;
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return ncclSuccess;
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}
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// Check topology / p2p level.
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int intermediateRank;
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NCCLCHECK(ncclTopoCheckP2p(topo, info1->busId, info2->busId, ret, NULL, &intermediateRank));
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if (*ret == 0) return ncclSuccess;
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if (intermediateRank != -1) return ncclSuccess;
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// Convert the peer's busId into a local cudaDev index (cf. CUDA_VISIBLE_DEVICES)
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int cudaDev1 = busIdToCudaDev(info1->busId);
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int cudaDev2 = busIdToCudaDev(info2->busId);
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if (cudaDev1 == -1 || cudaDev2 == -1) {
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#if CUDART_VERSION >= 10010
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// CUDA 10.1 and later can use P2P with invisible devices.
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return ncclSuccess;
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#else
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// Peer's CUDA device is not visible in this process : we can't communicate with it.
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*ret = 0;
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return ncclSuccess;
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#endif
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}
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// Check that CUDA can do P2P
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int p2p;
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if (cudaDeviceCanAccessPeer(&p2p, cudaDev1, cudaDev2) != cudaSuccess) {
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INFO(NCCL_INIT|NCCL_P2P,"peer query failed between dev %d(=%lx) and dev %d(=%lx)",
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cudaDev1, info1->busId, cudaDev2, info2->busId);
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*ret = 0;
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return ncclSuccess;
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}
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// Check that legacy IPC support is available
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if (p2p != 0) {
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char *dummy;
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cudaIpcMemHandle_t ipc;
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NCCLCHECK(ncclCudaCalloc(&dummy, CUDA_IPC_MIN));
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if (cudaIpcGetMemHandle(&ipc, dummy) != cudaSuccess) {
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INFO(NCCL_INIT|NCCL_P2P,"Legacy IPC not supported on dev %d(=%lx)",
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cudaDev1, info1->busId);
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*ret = 0;
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}
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CUDACHECK(cudaFree(dummy));
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return ncclSuccess;
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}
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if (p2p == 0) {
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INFO(NCCL_INIT|NCCL_P2P,"Could not enable P2P between dev %d(=%lx) and dev %d(=%lx)",
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cudaDev1, info1->busId, cudaDev2, info2->busId);
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*ret = 0;
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return ncclSuccess;
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}
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return ncclSuccess;
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}
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#define TRACE_DUMP_IPC(DEVIPC) \
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do { \
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unsigned long *devIpc = (unsigned long *) (DEVIPC); \
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TRACE(P2P,"IPC: %016lx %016lx %016lx %016lx", devIpc[0], devIpc[1], devIpc[2], devIpc[3]); \
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TRACE(P2P,"IPC: %016lx %016lx %016lx %016lx", devIpc[4], devIpc[5], devIpc[6], devIpc[7]); \
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} while (0)
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// Setting this to non zero causes P2P to use Reads rather than Writes
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NCCL_PARAM(P2pReadEnable, "P2P_READ_ENABLE", -2);
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static ncclResult_t p2pGetInfo(struct ncclTopoSystem* topo, struct ncclPeerInfo* info1, struct ncclPeerInfo* info2, int* read, int* intermediateRank) {
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int p2p;
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// Queries the topology to see if the GPUs are Ampere and
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// connected via NVLink, if so we enable P2P Read by default
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NCCLCHECK(ncclTopoCheckP2p(topo, info1->busId, info2->busId, &p2p, read, intermediateRank));
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int readEnable = ncclParamP2pReadEnable();
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if (readEnable != -2) *read = readEnable;
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return ncclSuccess;
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}
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static ncclResult_t p2pMap(struct ncclPeerInfo* myInfo, struct ncclPeerInfo* peerInfo, struct p2pConnectInfo* p2pInfo, void** devMem, void** ipcPtr) {
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if (myInfo->pidHash == peerInfo->pidHash) {
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if (peerInfo->cudaDev != myInfo->cudaDev) {
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// Enable P2P access
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cudaError_t err = cudaDeviceEnablePeerAccess(peerInfo->cudaDev, 0);
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if (err == cudaErrorPeerAccessAlreadyEnabled) {
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cudaGetLastError();
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} else if (err != cudaSuccess) {
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WARN("failed to peer with device %d(=%lx): %d %s",
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peerInfo->cudaDev, peerInfo->busId, err, cudaGetErrorString(err));
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return ncclInternalError;
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}
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}
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*devMem = p2pInfo->directPtr;
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*ipcPtr = NULL;
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} else {
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CUDACHECK(cudaIpcOpenMemHandle(devMem, p2pInfo->devIpc, cudaIpcMemLazyEnablePeerAccess));
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*ipcPtr = *devMem;
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}
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return ncclSuccess;
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}
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/* Send: Create and return connect structures for this peer to connect to me */
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ncclResult_t p2pSendSetup(struct ncclComm* comm, struct ncclTopoGraph* graph, struct ncclPeerInfo* myInfo, struct ncclPeerInfo* peerInfo,
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struct ncclConnect* connectInfo, struct ncclConnector* send, int channelId, int connIndex) {
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struct p2pSendResources* resources;
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NCCLCHECK(ncclCalloc(&resources, 1));
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send->transportResources = resources;
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int useRead, intermediateRank;
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NCCLCHECK(p2pGetInfo(comm->topo, myInfo, peerInfo, &useRead, &intermediateRank));
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struct p2pConnectInfo info;
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// For CollNet, we use write for scatter-reduce (conn 1), read for broadcast-gather (conn 0)
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info.read = (connIndex == 0) ? useRead : 0;
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const char* useReadStr = info.read ? "/read" : "";
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int sendSize = sizeof(struct ncclSendMem);
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// For P2P Read the SIMPLE buffer is tagged on the end of the ncclSendMem structure
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if (info.read) sendSize += send->comm->buffSizes[NCCL_PROTO_SIMPLE];
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ALIGN_SIZE(sendSize, CUDA_IPC_MIN);
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resources->remoteId = -1;
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resources->bootstrap = comm->bootstrap;
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if (intermediateRank == -1) {
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NCCLCHECK(ncclCudaCalloc((char**)&info.directPtr, sendSize));
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info.rank = myInfo->rank;
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if (myInfo->pidHash == peerInfo->pidHash) {
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send->conn.direct |= info.read ? NCCL_DIRECT_READ : NCCL_DIRECT_WRITE;
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INFO(NCCL_INIT|NCCL_P2P, "Channel %02d : %d[%lx] -> %d[%lx] via P2P/direct pointer%s",
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channelId, myInfo->rank, myInfo->busId, peerInfo->rank, peerInfo->busId, useReadStr);
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} else {
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send->conn.direct |= info.read ? NCCL_IPC_READ : NCCL_IPC_WRITE;
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CUDACHECK(cudaIpcGetMemHandle(&info.devIpc, info.directPtr));
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INFO(NCCL_INIT|NCCL_P2P,"Channel %02d : %d[%lx] -> %d[%lx] via P2P/IPC%s",
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channelId, myInfo->rank, myInfo->busId, peerInfo->rank, peerInfo->busId, useReadStr);
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}
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} else {
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NCCLCHECK(bootstrapRemAlloc(sendSize, intermediateRank, resources->bootstrap, &resources->remoteId, &info.devIpc, &info.directPtr));
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info.rank = intermediateRank;
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INFO(NCCL_INIT|NCCL_P2P, "Channel %02d : %d[%lx] -> %d[%lx] via P2P/indirect/%d[%lx]%s",
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channelId, myInfo->rank, myInfo->busId, peerInfo->rank, peerInfo->busId, intermediateRank,
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comm->peerInfo[intermediateRank].busId, useReadStr);
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}
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resources->memRank = info.rank;
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NCCLCHECK(p2pMap(myInfo, comm->peerInfo+info.rank, &info, (void**)&resources->devMem, &resources->ipcPtr));
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static_assert(sizeof(struct p2pConnectInfo) <= sizeof(struct ncclConnect), "p2p Connect Info is too big");
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memcpy(connectInfo, &info, sizeof(struct p2pConnectInfo));
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return ncclSuccess;
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}
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/* Create and return connect structures for this peer to connect to me */
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ncclResult_t p2pRecvSetup(struct ncclComm* comm, struct ncclTopoGraph* graph, struct ncclPeerInfo* myInfo, struct ncclPeerInfo* peerInfo,
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struct ncclConnect* connectInfo, struct ncclConnector * recv, int channelId, int connIndex) {
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struct p2pRecvResources* resources;
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NCCLCHECK(ncclCalloc(&resources, 1));
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recv->transportResources = resources;
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int useRead, intermediateRank;
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NCCLCHECK(p2pGetInfo(comm->topo, myInfo, peerInfo, &useRead, &intermediateRank));
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struct p2pConnectInfo info;
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// For CollNet, we use write for scatter-reduce (conn 1), read for broadcast-gather (conn 0)
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info.read = (connIndex == 0) ? useRead : 0;
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int recvSize = offsetof(struct ncclRecvMem, buff);
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// For P2P Read the SIMPLE buffer is tagged on the end of the ncclSendMem structure
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for (int p=0; p<NCCL_NUM_PROTOCOLS; p++) if (!(info.read && p == NCCL_PROTO_SIMPLE)) recvSize += recv->comm->buffSizes[p];
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ALIGN_SIZE(recvSize, CUDA_IPC_MIN);
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resources->remoteId = -1;
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resources->bootstrap = comm->bootstrap;
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if (intermediateRank == -1) {
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NCCLCHECK(ncclCudaCalloc((char**)&info.directPtr, recvSize));
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info.rank = myInfo->rank;
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if (myInfo->pidHash == peerInfo->pidHash) {
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recv->conn.direct |= info.read ? NCCL_DIRECT_READ : NCCL_DIRECT_WRITE;
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} else {
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recv->conn.direct |= info.read ? NCCL_IPC_READ : NCCL_IPC_WRITE;
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CUDACHECK(cudaIpcGetMemHandle(&info.devIpc, info.directPtr));
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}
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} else {
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NCCLCHECK(bootstrapRemAlloc(recvSize, intermediateRank, resources->bootstrap, &resources->remoteId, &info.devIpc, &info.directPtr));
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info.rank = intermediateRank;
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}
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resources->memRank = info.rank;
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NCCLCHECK(p2pMap(myInfo, comm->peerInfo+info.rank, &info, (void**)&resources->devMem, &resources->ipcPtr));
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static_assert(sizeof(struct p2pConnectInfo) <= sizeof(struct ncclConnect), "p2p Connect Info is too big");
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memcpy(connectInfo, &info, sizeof(struct p2pConnectInfo));
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return ncclSuccess;
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}
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/* Connect/Send to this peer */
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static ncclResult_t p2pSendConnect(struct ncclComm* comm, struct ncclConnect* connectInfo, int nranks, int rank, struct ncclConnector* send) {
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struct p2pSendResources* resources = (struct p2pSendResources*)send->transportResources;
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struct ncclRecvMem* remDevMem;
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struct p2pConnectInfo* info = (struct p2pConnectInfo*)connectInfo;
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NCCLCHECK(p2pMap(comm->peerInfo+rank, comm->peerInfo+info->rank, info, (void**)&remDevMem, &resources->remIpcPtr));
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int offset = 0;
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for (int p=0; p<NCCL_NUM_PROTOCOLS; p++) {
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if (info->read && p == NCCL_PROTO_SIMPLE) {
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/* For P2P Read the SIMPLE buffer is local (ncclSendMem) */
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send->conn.buffs[p] = resources->devMem->buff;
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} else {
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send->conn.buffs[p] = remDevMem->buff + offset;
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offset += send->comm->buffSizes[p];
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}
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}
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send->conn.tail = &remDevMem->tail;
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send->conn.head = &resources->devMem->head;
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send->conn.ptrExchange = &resources->devMem->ptrExchange;
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send->conn.redOpArgExchange = resources->devMem->redOpArgExchange;
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return ncclSuccess;
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}
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/* Connect/Recv from this peer */
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ncclResult_t p2pRecvConnect(struct ncclComm* comm, struct ncclConnect* connectInfo, int nranks, int rank, struct ncclConnector* recv) {
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struct p2pRecvResources* resources = (struct p2pRecvResources*)recv->transportResources;
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struct ncclSendMem* remDevMem;
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struct p2pConnectInfo* info = (struct p2pConnectInfo*)connectInfo;
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NCCLCHECK(p2pMap(comm->peerInfo+rank, comm->peerInfo+info->rank, info, (void**)&remDevMem, &resources->remIpcPtr));
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int offset = 0;
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for (int p=0; p<NCCL_NUM_PROTOCOLS; p++) {
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if (info->read && p == NCCL_PROTO_SIMPLE) {
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/* For P2P Read the SIMPLE buffer is remote (ncclSendMem) */
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recv->conn.buffs[p] = remDevMem->buff;
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} else {
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recv->conn.buffs[p] = resources->devMem->buff + offset;
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offset += recv->comm->buffSizes[p];
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}
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}
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recv->conn.tail = &resources->devMem->tail;
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recv->conn.head = &remDevMem->head;
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recv->conn.ptrExchange = &remDevMem->ptrExchange;
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recv->conn.redOpArgExchange = remDevMem->redOpArgExchange;
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return ncclSuccess;
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}
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ncclResult_t p2pSendFree(void* resources) {
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struct p2pSendResources* sendRes = (struct p2pSendResources*)resources;
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if (sendRes->ipcPtr)
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CUDACHECK(cudaIpcCloseMemHandle(sendRes->ipcPtr));
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if (sendRes->remIpcPtr)
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CUDACHECK(cudaIpcCloseMemHandle(sendRes->remIpcPtr));
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if (sendRes->remoteId != -1) {
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NCCLCHECK(bootstrapRemFree(sendRes->remoteId, sendRes->memRank, sendRes->bootstrap));
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sendRes->devMem = NULL;
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}
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CUDACHECK(cudaFree(sendRes->devMem));
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free(sendRes);
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return ncclSuccess;
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}
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ncclResult_t p2pRecvFree(void* resources) {
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struct p2pRecvResources* recvRes = (struct p2pRecvResources*)resources;
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if (recvRes->ipcPtr)
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CUDACHECK(cudaIpcCloseMemHandle(recvRes->ipcPtr));
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if (recvRes->remIpcPtr)
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CUDACHECK(cudaIpcCloseMemHandle(recvRes->remIpcPtr));
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if (recvRes->remoteId != -1) {
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NCCLCHECK(bootstrapRemFree(recvRes->remoteId, recvRes->memRank, recvRes->bootstrap));
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recvRes->devMem = NULL;
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}
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CUDACHECK(cudaFree(recvRes->devMem));
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free(recvRes);
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return ncclSuccess;
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}
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struct ncclTransport p2pTransport = {
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"P2P",
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p2pCanConnect,
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{ p2pSendSetup, p2pSendConnect, p2pSendFree, NULL },
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{ p2pRecvSetup, p2pRecvConnect, p2pRecvFree, NULL }
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};
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