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enqueue.cc
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enqueue.cc
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/*************************************************************************
* Copyright (c) 2017-2022, NVIDIA CORPORATION. All rights reserved.
*
* See LICENSE.txt for license information
************************************************************************/
#include "enqueue.h"
#include "argcheck.h"
#include "coll_net.h"
#include "gdrwrap.h"
#include "bootstrap.h"
#include "channel.h"
#include "cudawrap.h"
#include "profiler.h"
#include "transport.h"
#include <cstring> // std::memcpy
#include <cinttypes> // PRIx64
NCCL_PARAM(L1SharedMemoryCarveout, "L1_SHARED_MEMORY_CARVEOUT", 0);
// Returns maximum kernel stack size of all CUDA kernels
ncclResult_t ncclInitKernelsForDevice(int cudaArch, size_t* maxStackSize) {
ncclResult_t result = ncclSuccess;
if (maxStackSize) *maxStackSize = 0;
int carveout = ncclParamL1SharedMemoryCarveout();
for (int k=0; k < ncclDevKernelCount; k++) {
void* fn = ncclDevKernelList[k];
if (fn == nullptr) continue;
if (maxStackSize) {
cudaFuncAttributes attr = {0};
CUDACHECKGOTO(cudaFuncGetAttributes(&attr, fn), result, ignore0);
if (attr.localSizeBytes > *maxStackSize) *maxStackSize = attr.localSizeBytes;
ignore0:;
}
if (carveout) {
CUDACHECKGOTO(cudaFuncSetAttribute(fn,
cudaFuncAttributePreferredSharedMemoryCarveout, carveout),
result, ignore1);
ignore1:;
}
if (ncclShmemDynamicSize(cudaArch) != 0) {
CUDACHECKGOTO(cudaFuncSetAttribute(fn,
cudaFuncAttributeMaxDynamicSharedMemorySize, ncclShmemDynamicSize(cudaArch)),
result, next_kernel);
}
next_kernel:;
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
// Data movement metrics.
static inline int ncclFuncTrafficPerByte(ncclFunc_t func, int nRanks) {
switch (func) {
case ncclFuncAllReduce: return 2;
case ncclFuncAllGather: return nRanks;
case ncclFuncReduceScatter: return nRanks;
default: return 1;
}
}
static inline size_t ncclFuncSendCount(ncclFunc_t func, int nRanks, size_t count) {
return func == ncclFuncReduceScatter ? nRanks*count : count;
}
static inline size_t ncclFuncRecvCount(ncclFunc_t func, int nRanks, size_t count) {
return func == ncclFuncAllGather ? nRanks*count : count;
}
static inline size_t ncclFuncMaxSendRecvCount(ncclFunc_t func, int nRanks, size_t count) {
return func == ncclFuncAllGather || func == ncclFuncReduceScatter ? nRanks*count : count;
}
/*****************************************************************************/
/* Launch system : synchronization and CUDA kernel launch */
/*****************************************************************************/
static ncclResult_t addProxyOpIfNeeded(struct ncclComm* comm, struct ncclKernelPlan* plan, struct ncclProxyOp* op) {
bool needed = true;
NCCLCHECK(ncclProxySaveOp(comm, op, &needed));
if (needed) {
struct ncclProxyOp* q = ncclMemoryPoolAlloc<struct ncclProxyOp>(&comm->memPool_ncclProxyOp, &comm->memPermanent);
*q = *op; // C++ struct assignment
ncclIntruQueueEnqueue(&comm->planner.wipPlan.channels[op->channelId].proxyOpQueue, q);
}
return ncclSuccess;
}
static void addWorkBatchToPlan(
struct ncclComm* comm, struct ncclKernelPlan* plan, int channelId,
enum ncclDevWorkType workType, int devFuncId, uint32_t workOffset,
int p2pRound = -1
) {
ncclKernelPlanner::WipPlan::Channel* chan = &comm->planner.wipPlan.channels[channelId];
size_t workSize = ncclDevWorkSize(workType);
// Conditions causing us to create a new blank batch.
bool newBatch = (chan->workBatchQueue.tail == nullptr);
struct ncclDevWorkBatch* batch = nullptr;
if (!newBatch) {
batch = &chan->workBatchQueue.tail->batch;
// All of the conditions that prevent us from appending to current batch.
newBatch |= batch->workType != (uint8_t)workType;
newBatch |= batch->funcId != devFuncId;
// The following ensure the device can handle a batch this large. They have to
// account for all extension batches being fused together which is why
// wipBatch.workBytes and wipBatch.nP2ps aren't reset to 0 for a new extension
// batch further down.
newBatch |= NCCL_MAX_DEV_WORK_BATCH_BYTES < chan->wipBatch.workBytes + workSize;
if (workType == ncclDevWorkTypeP2p) {
newBatch |= chan->wipBatch.nP2ps == NCCL_MAX_DEV_WORK_P2P_PER_BATCH;
for (int i=0; i < chan->wipBatch.nP2ps; i++) {
newBatch |= p2pRound == chan->wipBatch.p2pRounds[i];
}
}
}
// Conditions causing us to create an extension batch (prev->nextExtends=1)
uint32_t offset = newBatch ? 0 : (workOffset - batch->offsetBase);
bool extendBatch = 63*workSize < offset;
extendBatch |= 0 != offset%workSize;
if (newBatch || extendBatch) {
if (!newBatch) batch->nextExtends = extendBatch; // Extending the previous batch.
struct ncclWorkBatchList* batchNode = ncclMemoryStackAlloc<ncclWorkBatchList>(&comm->memScoped);
// Coverity thinks that ncclIntruQueueEnqueue will access chan->workBatchQueue->tail, which might
// be NULL. But that code is guarded by chan->workBatchQueue->head not being NULL, in which
// case tail won't be NULL either.
// coverity[var_deref_model:FALSE]
ncclIntruQueueEnqueue(&chan->workBatchQueue, batchNode);
batch = &batchNode->batch;
batch->nextExtends = 0;
batch->workType = (uint32_t)workType;
batch->funcId = devFuncId;
batch->offsetBase = workOffset;
batch->offsetBitset = 0;
offset = 0;
if (newBatch) {
// Since extension batches are fused together on the device, and these values
// account for constraints on the fused batch, we only reset the values on
// a new batch
chan->wipBatch.workBytes = 0;
chan->wipBatch.nP2ps = 0;
// We don't count extension batches since this is used to derive a proxyOpCount,
// and we wan't all ops which are fused together to have the same value.
chan->nWorkBatchesP2p += (workType == ncclDevWorkTypeP2p ? 1 : 0);
}
plan->nWorkBatches += 1;
}
batch->offsetBitset |= 1ull<<(offset/workSize);
chan->wipBatch.workBytes += workSize;
if (workType == ncclDevWorkTypeP2p) {
// We need to ensure that a single batch doesn't have multiple p2p's
// of the same round since they would use the same connections.
chan->wipBatch.p2pRounds[chan->wipBatch.nP2ps++] = p2pRound;
}
}
static void finishPlan(struct ncclComm* comm, struct ncclKernelPlan* plan) {
ncclKernelPlanner::WipPlan::Channel* wipChannels = comm->planner.wipPlan.channels;
size_t workBytes = plan->workBytes;
size_t batchBytes = plan->nWorkBatches*sizeof(struct ncclDevWorkBatch);
plan->threadPerBlock = std::max(plan->threadPerBlock, NCCL_MIN_NTHREADS);
// If we can fit everything into the kernel args we do so.
if (sizeof(ncclDevKernelArgs) + batchBytes + workBytes <= comm->workArgsBytes) {
plan->workStorageType = ncclDevWorkStorageTypeArgs;
}
plan->kernelArgsSize = sizeof(struct ncclDevKernelArgs) + batchBytes;
plan->kernelArgsSize += (plan->workStorageType == ncclDevWorkStorageTypeArgs) ? workBytes : 0;
plan->kernelArgsSize = alignUp(plan->kernelArgsSize, 16);
plan->kernelArgs = (struct ncclDevKernelArgs*)ncclMemoryStackAlloc(&comm->memScoped, plan->kernelArgsSize, /*align=*/16);
plan->kernelArgs->comm = comm->devComm;
plan->kernelArgs->channelMask = plan->channelMask;
plan->kernelArgs->workStorageType = plan->workStorageType;
// Put batches into the kernel arguments. The first batch for each channel
// must be located at batchZero[blockIdx.x]. To achieve this we round robin
// over the channels in ascending order until they're exhausted.
uint64_t hasBatchMask = plan->channelMask;
struct ncclDevWorkBatch* batchPrev[MAXCHANNELS] = {}; // {0...}
struct ncclDevWorkBatch* batchZero = (struct ncclDevWorkBatch*)(plan->kernelArgs+1);
int batchIx = 0;
while (hasBatchMask != 0) {
uint64_t tmpMask = hasBatchMask; // channels with a batch for this round.
do {
int c = popFirstOneBit(&tmpMask);
if (!ncclIntruQueueEmpty(&wipChannels[c].workBatchQueue)) {
struct ncclWorkBatchList* batchNode = ncclIntruQueueDequeue(&wipChannels[c].workBatchQueue);
if (batchPrev[c] != nullptr) {
batchPrev[c]->nextJump = int(&batchZero[batchIx] - batchPrev[c]);
}
batchPrev[c] = &batchZero[batchIx];
batchZero[batchIx++] = batchNode->batch;
}
if (ncclIntruQueueEmpty(&wipChannels[c].workBatchQueue)) {
hasBatchMask ^= 1ull<<c;
}
} while (tmpMask != 0);
}
// Merge-sort per-channel proxy-op lists by opCount when merging them into plan->proxyOpQueue
// Phase 1: scan first op of each channel, store opCount in headIds[c].
uint64_t headIds[MAXCHANNELS];
int nHeads = 0;
int channelUbound = 0;
for (int c=0; c < MAXCHANNELS; c++) {
struct ncclProxyOp* op = ncclIntruQueueHead(&wipChannels[c].proxyOpQueue);
headIds[c] = op ? op->opCount : uint64_t(-1);
if (op) nHeads += 1;
if (op) plan->hasProxyOps = true;
if (op) channelUbound = c+1;
}
// Phase 2: Dequeue from planner->channels[c], enqueue in merged order to plan
while (nHeads != 0) {
int c = -1;
uint64_t minId = uint64_t(-1);
// Find channel with least proxy-op id. We store the heads[c]->opCount in
// headIds[c] to remove indirect loads from this loop.
for (int c1=0; c1 < channelUbound; c1++) {
uint64_t id = headIds[c1];
id = (id>>1 | id<<63); // Move tag bit to order collectives before p2p's
if (id < minId) { c = c1; minId = id; }
}
struct ncclProxyOp* op = ncclIntruQueueDequeue(&wipChannels[c].proxyOpQueue);
struct ncclProxyOp* opNext = ncclIntruQueueHead(&wipChannels[c].proxyOpQueue);
headIds[c] = opNext ? opNext->opCount : uint64_t(-1);
nHeads -= opNext ? 0 : 1;
ncclIntruQueueEnqueue(&plan->proxyOpQueue, op);
}
}
int64_t ncclParamLocalRegister();
NCCL_PARAM(GraphRegister, "GRAPH_REGISTER", 1);
struct ncclIpcCleanupCallback {
struct ncclCommCallback base;
void* ptr;
};
static ncclResult_t cleanupIpc(struct ncclComm* comm, struct ncclCommCallback* cb) {
struct ncclIpcCleanupCallback* me = (struct ncclIpcCleanupCallback*)cb;
CUDACHECKIGNORE(cudaIpcCloseMemHandle(me->ptr));
free(me);
return ncclSuccess;
}
static ncclResult_t registerCheckP2PConnection(struct ncclComm* comm, struct ncclConnector* conn, struct ncclTopoGraph* graph, int peer, bool* needReg) {
if (conn->connected) {
if (conn->conn.flags & (NCCL_IPC_READ | NCCL_IPC_WRITE | NCCL_DIRECT_READ | NCCL_DIRECT_WRITE)) {
*needReg = true;
} else {
// network connection
*needReg = false;
}
} else {
struct ncclPeerInfo* peerInfo = &comm->peerInfo[peer];
struct ncclPeerInfo* myInfo = &comm->peerInfo[comm->rank];
int canConnect = 0;
NCCLCHECK(ncclTransports[0]->canConnect(&canConnect, comm, graph, myInfo, peerInfo));
if (canConnect) {
*needReg = true;
} else {
*needReg = false;
}
}
return ncclSuccess;
}
static ncclResult_t registerCollBuffers(
struct ncclComm* comm, struct ncclTaskColl* info,
void* outRegBufSend[NCCL_MAX_LOCAL_RANKS],
void* outRegBufRecv[NCCL_MAX_LOCAL_RANKS],
struct ncclIntruQueue<struct ncclCommCallback, &ncclCommCallback::next>* cleanupQueue,
bool* regNeedConnect
) {
ncclResult_t result = ncclSuccess;
info->regBufType = NCCL_REGULAR_BUFFER;
*regNeedConnect = true;
if (!(ncclParamLocalRegister() || (comm->planner.persistent && ncclParamGraphRegister()))) goto exit;
#if CUDART_VERSION >= 11030
if (info->algorithm == NCCL_ALGO_NVLS || info->algorithm == NCCL_ALGO_NVLS_TREE) {
if (!comm->nvlsRegSupport || info->opDev.op == ncclDevPreMulSum) goto exit;
bool regBufUsed = false;
const void *sendbuff = info->sendbuff;
void *recvbuff = info->recvbuff;
if (info->func == ncclFuncAllGather) sendbuff = NULL;
if (info->func == ncclFuncReduceScatter) recvbuff = NULL;
size_t elementSize = ncclTypeSize(info->datatype);
size_t sendbuffSize = elementSize*ncclFuncSendCount(info->func, comm->nRanks, info->count);
size_t recvbuffSize = elementSize*ncclFuncRecvCount(info->func, comm->nRanks, info->count);
/* first try local registration. */
if (ncclParamLocalRegister()) {
ncclNvlsLocalRegisterBuffer(comm, sendbuff, recvbuff, sendbuffSize, recvbuffSize, ®BufUsed, outRegBufSend, outRegBufRecv);
}
if (regBufUsed == false && comm->planner.persistent && ncclParamGraphRegister()) {
ncclNvlsGraphRegisterBuffer(comm, sendbuff, recvbuff, sendbuffSize, recvbuffSize, ®BufUsed, outRegBufSend, outRegBufRecv, cleanupQueue, &info->nCleanupQueueElts);
}
if (regBufUsed) {
*regNeedConnect = false;
/* tweak NVLS channels usage; for registered NVLS buffer, we only need 4/5 channels to
* saturate bandwidth. */
if (comm->nNodes == 1) {
if (info->func == ncclFuncReduceScatter)
info->nMaxChannels = std::max(comm->config.minCTAs, std::min(comm->config.maxCTAs, 5));
else
info->nMaxChannels = std::max(comm->config.minCTAs, std::min(comm->config.maxCTAs, 4));
} else {
info->nMaxChannels = std::max(comm->config.minCTAs, std::min(comm->config.maxCTAs, 6));
}
info->regBufType = NCCL_NVLS_REG_BUFFER;
}
} else if ((info->algorithm == NCCL_ALGO_COLLNET_DIRECT || info->algorithm == NCCL_ALGO_COLLNET_CHAIN) && comm->collNetRegSupport && info->opDev.op != ncclDevPreMulSum && info->opDev.op != ncclDevSumPostDiv) {
size_t elementSize = ncclTypeSize(info->datatype);
size_t sendbuffSize = elementSize*ncclFuncSendCount(info->func, comm->nRanks, info->count);
size_t recvbuffSize = elementSize*ncclFuncRecvCount(info->func, comm->nRanks, info->count);
int sendRegBufFlag = 0;
int recvRegBufFlag = 0;
void *sendHandle, *recvHandle;
if (ncclParamLocalRegister()) {
ncclCollnetLocalRegisterBuffer(comm, info->sendbuff, sendbuffSize, collNetSend, &sendRegBufFlag, &sendHandle);
info->sendMhandle = sendHandle;
if (sendRegBufFlag) {
ncclCollnetLocalRegisterBuffer(comm, info->recvbuff, recvbuffSize, collNetRecv, &recvRegBufFlag, &recvHandle);
info->recvMhandle = recvHandle;
}
}
if ((sendRegBufFlag == 0 || recvRegBufFlag == 0) && comm->planner.persistent && ncclParamGraphRegister()) {
if (!sendRegBufFlag) {
ncclCollnetGraphRegisterBuffer(comm, info->sendbuff, sendbuffSize, collNetSend, &sendRegBufFlag, &sendHandle, cleanupQueue, &info->nCleanupQueueElts);
info->sendMhandle = sendHandle;
}
if (sendRegBufFlag && !recvRegBufFlag) {
ncclCollnetGraphRegisterBuffer(comm, info->recvbuff, recvbuffSize, collNetRecv, &recvRegBufFlag, &recvHandle, cleanupQueue, &info->nCleanupQueueElts);
info->recvMhandle = recvHandle;
}
}
if (sendRegBufFlag && recvRegBufFlag) {
info->nMaxChannels = 1;
info->regBufType = NCCL_COLLNET_REG_BUFFER;
if (sendRegBufFlag == 1 && recvRegBufFlag == 1) {
INFO(NCCL_REG, "rank %d successfully registered collNet sendbuff %p (handle %p), sendbuff size %ld, recvbuff %p (handle %p), recvbuff size %ld", comm->rank, info->sendbuff, sendHandle, sendbuffSize, info->recvbuff, recvHandle, recvbuffSize);
}
}
} else if (comm->intraNodeP2pSupport && info->protocol == NCCL_PROTO_SIMPLE) {
// IPC buffer registration
if (info->func == ncclFuncReduceScatter) goto exit;
if (info->algorithm == NCCL_ALGO_RING && ((info->func == ncclFuncAllReduce && info->sendbuff == info->recvbuff) || info->func == ncclFuncReduce)) goto exit;
if ((info->algorithm == NCCL_ALGO_TREE || info->algorithm == NCCL_ALGO_COLLNET_CHAIN) && info->sendbuff == info->recvbuff) goto exit;
if (info->func == ncclFuncAllGather && info->algorithm == NCCL_ALGO_PAT) goto exit;
int peerRanks[NCCL_MAX_LOCAL_RANKS];
int nPeers = 0;
size_t elementSize = ncclTypeSize(info->datatype);
size_t sendbuffSize = elementSize*ncclFuncSendCount(info->func, comm->nRanks, info->count);
size_t recvbuffSize = elementSize*ncclFuncRecvCount(info->func, comm->nRanks, info->count);
int regBufFlag = 0;
memset(peerRanks, 0xff, sizeof(int) * NCCL_MAX_LOCAL_RANKS);
if (info->algorithm == NCCL_ALGO_COLLNET_DIRECT) {
struct ncclChannel* channel = comm->channels;
for (int r = 0; r < NCCL_MAX_DIRECT_ARITY; ++r) {
for (int updown = 0; updown < 2; ++updown) {
int peer;
if (updown == 0)
peer = channel->collnetDirect.up[r];
else
peer = channel->collnetDirect.down[r];
if (peer != -1) {
struct ncclConnector* peerConn = &channel->peers[peer]->recv[0];
bool needReg = false;
NCCLCHECK(registerCheckP2PConnection(comm, peerConn, &comm->graphs[NCCL_ALGO_COLLNET_DIRECT], peer, &needReg));
if (needReg) {
bool found = false;
for (int p = 0; p < nPeers; ++p) {
if (peerRanks[p] == peer) {
found = true;
break;
}
}
if (!found) peerRanks[nPeers++] = peer;
}
}
}
}
if (nPeers > 0) {
if (ncclParamLocalRegister())
ncclIpcLocalRegisterBuffer(comm, info->sendbuff, sendbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->sendbuffOffset, &info->sendbuffRmtAddrs);
if (!regBufFlag && comm->planner.persistent && ncclParamGraphRegister()) {
ncclIpcGraphRegisterBuffer(comm, info->sendbuff, sendbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->sendbuffOffset, &info->sendbuffRmtAddrs, cleanupQueue, &info->nCleanupQueueElts);
}
if (regBufFlag) {
if (ncclParamLocalRegister())
ncclIpcLocalRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs);
if (!regBufFlag && comm->planner.persistent && ncclParamGraphRegister()) {
ncclIpcGraphRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs, cleanupQueue, &info->nCleanupQueueElts);
}
}
}
if (regBufFlag) {
info->regBufType = NCCL_IPC_REG_BUFFER;
}
} else if (info->algorithm == NCCL_ALGO_RING) {
struct ncclReg* recvRegRecord;
NCCLCHECK(ncclRegFind(comm, info->recvbuff, recvbuffSize, &recvRegRecord));
if (recvRegRecord == NULL) goto exit;
for (int c = 0; c < comm->nChannels; ++c) {
struct ncclChannel* channel = comm->channels + c;
for (int r = 0; r < 2; ++r) {
bool needReg = false;
int peer;
struct ncclConnector* peerConn;
// P2P transport
if (r == 0)
peer = channel->ring.prev;
else
peer = channel->ring.next;
peerConn = &channel->peers[peer]->recv[0];
NCCLCHECK(registerCheckP2PConnection(comm, peerConn, &comm->graphs[NCCL_ALGO_RING], peer, &needReg));
if (needReg) {
bool found = false;
for (int p = 0; p < nPeers; ++p) {
if (peerRanks[p] == peer) {
found = true;
break;
}
}
if (!found) peerRanks[nPeers++] = peer;
}
}
}
if (nPeers > 0) {
if (ncclParamLocalRegister()) {
ncclIpcLocalRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs);
}
if (!regBufFlag && comm->planner.persistent && ncclParamGraphRegister()) {
ncclIpcGraphRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs, cleanupQueue, &info->nCleanupQueueElts);
}
}
if (regBufFlag) {
info->regBufType = NCCL_IPC_REG_BUFFER;
}
} else if (info->algorithm == NCCL_ALGO_TREE || info->algorithm == NCCL_ALGO_COLLNET_CHAIN) {
struct ncclReg* recvRegRecord;
NCCLCHECK(ncclRegFind(comm, info->recvbuff, recvbuffSize, &recvRegRecord));
if (recvRegRecord == NULL) goto exit;
for (int c = 0; c < comm->nChannels; ++c) {
struct ncclChannel* channel = comm->channels + c;
struct ncclTree* tree = NULL;
int peers[NCCL_MAX_TREE_ARITY + 1];
if (info->algorithm == NCCL_ALGO_TREE)
tree = &channel->tree;
else
tree = &channel->collnetChain;
for (int p = 0; p < NCCL_MAX_TREE_ARITY; ++p) peers[p] = tree->down[p];
peers[NCCL_MAX_TREE_ARITY] = tree->up;
for (int p = 0; p < NCCL_MAX_TREE_ARITY + 1; ++p) {
int peer = peers[p];
bool peerNeedReg = false;
struct ncclConnector* recvConn = NULL;
// P2P transport
if (peer == -1 || peer == comm->nRanks) continue;
recvConn = &channel->peers[peer]->recv[0];
NCCLCHECK(registerCheckP2PConnection(comm, recvConn, &comm->graphs[info->algorithm], peer, &peerNeedReg));
if (peerNeedReg) {
bool found = false;
for (int pindex = 0; pindex < nPeers; ++pindex) {
if (peerRanks[pindex] == peer) {
found = true;
break;
}
}
if (!found) peerRanks[nPeers++] = peer;
}
}
}
if (nPeers > 0) {
if (ncclParamLocalRegister()) {
ncclIpcLocalRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs);
}
if (!regBufFlag && comm->planner.persistent && ncclParamGraphRegister()) {
ncclIpcGraphRegisterBuffer(comm, info->recvbuff, recvbuffSize, peerRanks, nPeers, NCCL_IPC_COLLECTIVE, ®BufFlag, &info->recvbuffOffset, &info->recvbuffRmtAddrs, cleanupQueue, &info->nCleanupQueueElts);
}
}
if (regBufFlag) {
info->regBufType = NCCL_IPC_REG_BUFFER;
}
}
if (info->regBufType == NCCL_IPC_REG_BUFFER && comm->nNodes == 1 && 16 < info->nMaxChannels && info->nMaxChannels <= 24) {
info->nMaxChannels = 16;
}
}
exit:
#endif
return result;
}
static ncclResult_t registerP2pBuffer(struct ncclComm* comm, void* userbuff, int peerRank, size_t size, int* regFlag, void** regAddr, struct ncclIntruQueue<struct ncclCommCallback, &ncclCommCallback::next>* cleanupQueue) {
ncclResult_t ret = ncclSuccess;
uintptr_t offset = 0;
uintptr_t* peerRmtAddrs = NULL;
*regFlag = 0;
if (ncclParamLocalRegister()) {
ncclIpcLocalRegisterBuffer(comm, userbuff, size, &peerRank, 1, NCCL_IPC_SENDRECV, regFlag, &offset, &peerRmtAddrs);
}
if (*regFlag == 0 && comm->planner.persistent && ncclParamGraphRegister()) {
ncclIpcGraphRegisterBuffer(comm, userbuff, size, &peerRank, 1, NCCL_IPC_SENDRECV, regFlag, &offset, &peerRmtAddrs, reinterpret_cast<void*>(cleanupQueue), NULL);
}
if (*regFlag)
*regAddr = (void*)((uintptr_t)peerRmtAddrs + offset);
return ret;
}
static ncclResult_t getCollNetSupport(struct ncclComm* comm, struct ncclTaskColl* task, int* collNetSupport);
static ncclResult_t getAlgoInfo(
struct ncclComm* comm, struct ncclTaskColl* task,
int collNetSupport, int nvlsSupport, int numPipeOps, ncclSimInfo_t* simInfo = NULL
);
static ncclResult_t calcCollChunking(
struct ncclComm* comm, struct ncclTaskColl* task, int nChannels, size_t nBytes,
/*outputs*/uint32_t* outChunkSize, uint32_t* outDirectFlags, struct ncclProxyOp* proxyOp
);
struct ncclKernelPlanBudget {
ssize_t inArgsBytes; // Space available within kernel args struct
ssize_t outArgsBytes; // Space available outside of args struct (fifo or persistent buf)
};
static bool testBudget(
struct ncclKernelPlanBudget* budget, int nWorkBatches, ssize_t workBytes
) {
ssize_t batchBytes = nWorkBatches*sizeof(struct ncclDevWorkBatch);
bool ok = false;
ok |= (batchBytes + workBytes <= budget->inArgsBytes);
ok |= (batchBytes <= budget->inArgsBytes) && (workBytes <= budget->outArgsBytes);
return ok;
}
// Called once per ncclGroup to organize the user submitted tasks in
// comm->planner so that they can be peeled off into plans.
ncclResult_t ncclPrepareTasks(struct ncclComm* comm, bool* algoNeedConnect, bool* needConnect, ncclSimInfo_t* simInfo) {
struct ncclKernelPlanner* planner = &comm->planner;
// Tasks from the sorter come out ordered size descending.
struct ncclTaskColl* task = ncclTaskCollSorterDequeueAll(&planner->collSorter);
// Tasks are assembled by (fn,op,ty) size ascending.
struct ncclTaskColl* tasksByFnOpTy[ncclNumFuncs*ncclNumDevRedOps*ncclNumTypes];
memset(tasksByFnOpTy, 0, sizeof(tasksByFnOpTy));
int fnOpTyIndices[ncclNumFuncs*ncclNumDevRedOps*ncclNumTypes];
int fnOpTyCount = 0;
// Walk the size sorted tasks, binning them by (fn,op,ty).
while (task != nullptr) {
struct ncclTaskColl* next = task->next;
int index = ((int)task->func*ncclNumDevRedOps + (int)task->opDev.op)*ncclNumTypes + (int)task->datatype;
// Add to set of (fn,op,ty) indices on first occurrence
if (tasksByFnOpTy[index] == nullptr) fnOpTyIndices[fnOpTyCount++] = index;
// Add to LIFO for this (fn,op,ty)
task->next = tasksByFnOpTy[index];
tasksByFnOpTy[index] = task;
// Next task
task = next;
}
// Walk (fn,op,ty) bins, compute algo and proto etc. Then bin them by their
// scheduling constraints (collnet x nvls).
struct ncclIntruQueue<struct ncclTaskColl, &ncclTaskColl::next> collBins[2][2] = {};
for (int cursor=0; cursor < fnOpTyCount; cursor++) {
struct ncclTaskColl* aggBeg = tasksByFnOpTy[fnOpTyIndices[cursor]];
int collNetSupport = 0;
NCCLCHECK(getCollNetSupport(comm, aggBeg, &collNetSupport));
int nvlsSupport = comm->nvlsSupport && (ncclNvlsSupported(aggBeg->opDev.op, aggBeg->datatype) || aggBeg->func == ncclFuncAllGather);
// Crudely estimate number of tasks per channel. This is using the wrong number
// of channels for NVLS algos, but knowing the algo requires having this value,
// so either be crude our iterate until fixed point, we chose the former.
int nTasksPerChannel = divUp(comm->planner.nTasksColl, comm->nChannels);
do {
struct ncclTaskColl* aggEnd = aggBeg->next;
struct ncclTaskColl agg = *aggBeg;
// We aggregate operations that are within 4X size of each other.
while (aggEnd != nullptr && aggEnd->trafficBytes < 4*aggBeg->trafficBytes) {
agg.count += aggEnd->count;
agg.trafficBytes += aggEnd->trafficBytes;
aggEnd = aggEnd->next;
}
NCCLCHECK(getAlgoInfo(comm, &agg, collNetSupport, nvlsSupport, nTasksPerChannel, simInfo));
agg.devFuncId = ncclDevFuncId(agg.func, agg.opDev.op, agg.datatype, agg.algorithm, agg.protocol);
int isCollnet=0, isNvls=0;
switch (agg.algorithm) {
case NCCL_ALGO_NVLS:
case NCCL_ALGO_NVLS_TREE:
isNvls = 1;
isCollnet = agg.algorithm == NCCL_ALGO_NVLS && comm->nNodes > 1;
break;
case NCCL_ALGO_COLLNET_CHAIN:
case NCCL_ALGO_COLLNET_DIRECT:
isCollnet = 1;
break;
}
// Update the aggregated tasks with the computed values.
do {
struct ncclTaskColl* next = aggBeg->next;
aggBeg->algorithm = agg.algorithm;
aggBeg->protocol = agg.protocol;
aggBeg->nMaxChannels = agg.nMaxChannels;
aggBeg->nWarps = agg.nWarps;
aggBeg->devFuncId = agg.devFuncId;
aggBeg->isCollnet = isCollnet;
aggBeg->isNvls = isNvls;
ncclIntruQueueEnqueue(&collBins[isCollnet][isNvls], aggBeg);
aggBeg = next;
} while (aggBeg != aggEnd);
} while (aggBeg != nullptr);
}
// Concatenate `collBins[*][*]` together into final list `planner->collTaskQueue`.
// Collnet is the outer dimension since that affects how we divide over the
// channels.
for (int isCollnet=0; isCollnet <= 1; isCollnet++) {
for (int isNvls=0; isNvls <= 1; isNvls++) {
ncclIntruQueueTransfer(&planner->collTaskQueue, &collBins[isCollnet][isNvls]);
}
}
// Walk tasks again to:
// 1. Possibly register buffers.
// 2. Build ncclDevWorkColl structs.
// 3. Bin the work structs according to the number of valid channels they
// may be assigned to {collnet, nvls, standard}
task = ncclIntruQueueHead(&planner->collTaskQueue);
while (task != nullptr) {
// Build a ncclDevWorkColl[Reg?] struct for each task.
void* regBufSend[NCCL_MAX_LOCAL_RANKS];
void* regBufRecv[NCCL_MAX_LOCAL_RANKS];
bool regNeedConnect = true;
registerCollBuffers(comm, task, regBufSend, regBufRecv, &planner->collCleanupQueue, ®NeedConnect);
if (comm->runtimeConn && comm->initAlgoChannels[task->algorithm] == false) {
if (task->algorithm == NCCL_ALGO_NVLS_TREE && comm->initAlgoChannels[NCCL_ALGO_NVLS] == false && regNeedConnect == true) {
comm->initAlgoChannels[NCCL_ALGO_NVLS] = true;
algoNeedConnect[NCCL_ALGO_NVLS] = true;
}
if (task->algorithm != NCCL_ALGO_NVLS || regNeedConnect == true) {
comm->initAlgoChannels[task->algorithm] = true;
algoNeedConnect[task->algorithm] = true;
*needConnect = true;
}
}
struct ncclDevWorkColl devWork = {};
devWork.sendbuff = (void*)task->sendbuff;
devWork.recvbuff = (void*)task->recvbuff;
devWork.sendbuffOffset = task->sendbuffOffset;
devWork.recvbuffOffset = task->recvbuffOffset;
devWork.sendbuffRmtAddrs = task->sendbuffRmtAddrs;
devWork.recvbuffRmtAddrs = task->recvbuffRmtAddrs;
devWork.root = task->root;
devWork.nWarps = task->nWarps;
devWork.redOpArg = task->opDev.scalarArg;
devWork.redOpArgIsPtr = task->opDev.scalarArgIsPtr;
devWork.oneNode = (comm->nNodes == 1);
devWork.regUsed = task->regBufType;
struct ncclWorkList* workNode;
switch (task->regBufType) {
case NCCL_REGULAR_BUFFER:
case NCCL_IPC_REG_BUFFER:
case NCCL_COLLNET_REG_BUFFER:
{ workNode = ncclMemoryStackAllocInlineArray<ncclWorkList, ncclDevWorkColl>(&comm->memScoped, 1);
workNode->workType = ncclDevWorkTypeColl;
workNode->size = sizeof(struct ncclDevWorkColl);
memcpy((void*)(workNode+1), (void*)&devWork, workNode->size);
} break;
case NCCL_NVLS_REG_BUFFER:
{ struct ncclDevWorkCollReg workReg = {};
workReg.coll = devWork; // C++ struct assignment
/* NVLS only has one send and recv buffer registered */
workReg.dnInputs[0] = regBufSend[0];
workReg.dnOutputs[0] = regBufRecv[0];
workNode = ncclMemoryStackAllocInlineArray<ncclWorkList, ncclDevWorkCollReg>(&comm->memScoped, 1);
workNode->workType = ncclDevWorkTypeCollReg;
workNode->size = sizeof(struct ncclDevWorkCollReg);
memcpy((void*)(workNode+1), (void*)&workReg, workNode->size);
} break;
default:
/* impossible value */
WARN("Invalid regBufType %d", task->regBufType);
return ncclInvalidArgument;
}
ncclIntruQueueEnqueue(&planner->collWorkQueue, workNode);
task = task->next;
}
return ncclSuccess;
}
static ncclResult_t scheduleCollTasksToPlan(
struct ncclComm* comm, struct ncclKernelPlan* plan, struct ncclKernelPlanBudget* budget
) {
struct ncclKernelPlanner* planner = &comm->planner;
// Estimate number of tasks that will fit in this plan.
int nPlanColls = 0;
size_t trafficBytes[2*2] = {0, 0, 0, 0}; // [collnet][nvls]
int nChannels[2*2] = {0, 0, 0, 0}; // [collnet][nvls]
int const nMaxChannels[2*2] = {comm->nChannels, comm->nvlsChannels, // [collnet][nvls]
comm->nChannels, comm->nvlsChannels};
constexpr size_t MinTrafficPerChannel = 16 << 10; // 16K traffic as minimal
do {
size_t workBytes = 0;
struct ncclTaskColl* task = ncclIntruQueueHead(&planner->collTaskQueue);
struct ncclWorkList* workNode = ncclIntruQueueHead(&planner->collWorkQueue);
while (task != nullptr) {
int nBatches = divUp(nPlanColls, 4); // Rough guess: 4 colls per batch.
if (!testBudget(budget, nBatches, workBytes + workNode->size)) goto plan_full;
nPlanColls += 1;
workBytes += workNode->size;
int kind = 2*task->isCollnet + task->isNvls;
trafficBytes[kind] += std::max(MinTrafficPerChannel, task->trafficBytes);
nChannels[kind] += task->nMaxChannels;
nChannels[kind] = std::min(nChannels[kind], nMaxChannels[kind]);
task = task->next;
workNode = workNode->next;
}
plan_full:;
} while (0);
int kindPrev = -1;
size_t trafficPerChannel = 0;
int channelId = 0;
size_t currentTraffic = 0;
while (nPlanColls!=0 && !ncclIntruQueueEmpty(&planner->collTaskQueue)) {
struct ncclTaskColl* task = ncclIntruQueueHead(&planner->collTaskQueue);
struct ncclWorkList* workNode = ncclIntruQueueHead(&planner->collWorkQueue);
struct ncclDevWorkColl* devWork = (struct ncclDevWorkColl*)(workNode+1);
size_t elementSize = ncclTypeSize(task->datatype);
int kind = 2*task->isCollnet + task->isNvls;
if (kind != kindPrev) {
trafficPerChannel = std::max<size_t>(MinTrafficPerChannel, trafficBytes[kind]/nChannels[kind]);
kindPrev = kind;
channelId = 0;
currentTraffic = 0;
}
if (task->isCollnet) {
int nChannels = task->nMaxChannels;
// Ensure room for worst case of one new batch per channel
if (!testBudget(budget, plan->nWorkBatches + nChannels, plan->workBytes + workNode->size)) {
return ncclSuccess;
}
size_t globalBytesPerElement = elementSize*ncclFuncMaxSendRecvCount(task->func, comm->nRanks, 1);
struct ncclProxyOp proxyOp;
uint32_t chunkSize, directFlags=0;
NCCLCHECK(calcCollChunking(comm, task, nChannels, globalBytesPerElement*task->count, &chunkSize, &directFlags, &proxyOp));
devWork->channelLo = 0;
devWork->channelHi = nChannels-1;
devWork->collnet.count = task->count;
devWork->collnet.chunkCount = chunkSize/ncclTypeSize(task->datatype);
devWork->direct = directFlags;
uint64_t proxyOpId = uint64_t(plan->collOpCount++)<<1 | 0;
for (int c=devWork->channelLo; c <= (int)devWork->channelHi; c++) {
proxyOp.channelId = c;
proxyOp.opCount = proxyOpId;
proxyOp.task.coll = task;
proxyOp.rank = comm->rank;
addWorkBatchToPlan(comm, plan, c, workNode->workType, task->devFuncId, plan->workBytes);
NCCLCHECK(addProxyOpIfNeeded(comm, plan, &proxyOp));
}
} else { // not task->isCollnet
int trafficPerByte = ncclFuncTrafficPerByte(task->func, comm->nRanks);
size_t cellSize = divUp(divUp(MinTrafficPerChannel, (size_t)trafficPerByte), 16) * 16;
int elementsPerCell = cellSize/elementSize;
size_t cells = divUp(task->count*elementSize, cellSize);
size_t trafficPerElement = elementSize*trafficPerByte;
size_t trafficPerCell = cellSize*trafficPerByte;
size_t cellsPerChannel = std::min(cells, divUp(trafficPerChannel, trafficPerCell));
size_t cellsLo;
if (channelId+1 == nMaxChannels[kind]) { // On last channel everything goes to "lo"
cellsLo = cells;
} else {
cellsLo = std::min(cells, divUp((trafficPerChannel-currentTraffic),trafficPerCell));
}
int nMidChannels = (cells-cellsLo)/cellsPerChannel;
size_t cellsHi = (cells-cellsLo)%cellsPerChannel;
int nChannels = (cellsLo!=0 ? 1 : 0) + nMidChannels + (cellsHi!=0 ? 1 : 0);
if (nMaxChannels[kind] < channelId + nChannels) { // Overflowed available channels
nMidChannels = nMaxChannels[kind] - channelId - 2;
cellsPerChannel = (cells-cellsLo)/(nMidChannels+1);
cellsHi = cellsPerChannel + (cells-cellsLo)%(nMidChannels+1);
}
if (cellsHi == 0 && nMidChannels != 0) {
cellsHi = cellsPerChannel;
nMidChannels -= 1;
}
if (cellsLo == 0) { // Least channel skipped. Make the next channel the new least.
channelId += 1;
if (nMidChannels == 0) { cellsLo = cellsHi; cellsHi = 0; }
else { cellsLo = cellsPerChannel; nMidChannels -= 1; }
}
size_t countMid = nMidChannels!=0 ? cellsPerChannel*elementsPerCell : 0;
size_t countLo = cellsLo*elementsPerCell;
size_t countHi = cellsHi*elementsPerCell;
(countHi != 0 ? countHi : countLo) -= cells*elementsPerCell - task->count;
nChannels = (countLo!=0 ? 1 : 0) + nMidChannels + (cellsHi!=0 ? 1 : 0);
// Ensure room for worst case of one new batch per channel
if (!testBudget(budget, plan->nWorkBatches + nChannels, plan->workBytes + workNode->size)) {
return ncclSuccess;
}
devWork->channelLo = channelId;
devWork->channelHi = channelId + nChannels-1;
devWork->cbd.countLo = countLo;
devWork->cbd.countMid = countMid;
devWork->cbd.countHi = countHi;
// calcCollChunking() uses global bytes instead of traffic which differs
// in that allreduce isn't multiplied by 2.
size_t globalBytesPerElement = elementSize*ncclFuncMaxSendRecvCount(task->func, comm->nRanks, 1);
struct ncclProxyOp proxyOpLo, proxyOpMid, proxyOpHi;
uint32_t chunkSize, directFlags=0;
size_t grainSize = ncclProtoGrainSize(task->protocol);
if (countLo != 0) {
NCCLCHECK(calcCollChunking(comm, task, /*nChannels=*/1, globalBytesPerElement*countLo, &chunkSize, &directFlags, &proxyOpLo));
devWork->cbd.chunkGrainsLo = chunkSize/grainSize;
}
if (countHi != 0) {
NCCLCHECK(calcCollChunking(comm, task, /*nChannels=*/1, globalBytesPerElement*countHi, &chunkSize, &directFlags, &proxyOpHi));
devWork->cbd.chunkGrainsHi = chunkSize/grainSize;
}
if (nMidChannels != 0) {
NCCLCHECK(calcCollChunking(comm, task, /*nChannels=*/1, globalBytesPerElement*countMid, &chunkSize, &directFlags, &proxyOpMid));
devWork->cbd.chunkGrainsMid = chunkSize/grainSize;
}
devWork->direct = directFlags;
// Update the current channel and vacant traffic budget.
if (countHi != 0) {
channelId += nChannels-1;
currentTraffic = cellsHi*elementsPerCell*trafficPerElement;
} else if (nMidChannels != 0) {
channelId += nChannels;
currentTraffic = 0;
} else {
currentTraffic += cellsLo*elementsPerCell*trafficPerElement;
}
if (currentTraffic >= trafficPerChannel && channelId+1 != nMaxChannels[kind]) {
channelId += 1;
currentTraffic = 0;
}
uint64_t proxyOpId = uint64_t(plan->collOpCount++)<<1 | 0;
for (int c=devWork->channelLo; c <= (int)devWork->channelHi; c++) {
struct ncclProxyOp* proxyOp;
if (c == (int)devWork->channelLo) {
proxyOp = &proxyOpLo;
} else if (c == (int)devWork->channelHi) {
proxyOp = &proxyOpHi;
} else {
proxyOp = &proxyOpMid;
}
proxyOp->channelId = c;
proxyOp->opCount = proxyOpId;
proxyOp->task.coll = task;
proxyOp->rank = comm->rank;
addWorkBatchToPlan(comm, plan, c, workNode->workType, task->devFuncId, plan->workBytes);
// Coverity reports "proxyOp->connection" as being possibly uninitialized. It's hard to
// determine if that's actually true but it's also not clear if that would be an issue.
// coverity[uninit_use_in_call:FALSE]
NCCLCHECK(addProxyOpIfNeeded(comm, plan, proxyOp));
}
}
plan->channelMask |= (2ull<<devWork->channelHi) - (1ull<<devWork->channelLo);
plan->threadPerBlock = std::max(plan->threadPerBlock, task->nWarps*WARP_SIZE);
if (!plan->kernelSpecialized) {
plan->kernelFn = ncclDevKernelForFunc[task->devFuncId];
plan->kernelSpecialized = ncclDevKernelForFuncIsSpecialized[task->devFuncId];
}
if (comm->rank == 0) {
if (task->isCollnet) {
TRACE(NCCL_COLL, "Collective %s(%s, %s, %s, %s) count=%ld devFuncId=%d channel{Lo..Hi}={%d..%d} count=%ld chunkCount=%d",
ncclFuncToString(task->func), ncclDevRedOpToString(task->opDev.op),
ncclDatatypeToString(task->datatype), ncclAlgoToString(task->algorithm),
ncclProtoToString(task->protocol),
(long)task->count, task->devFuncId, devWork->channelLo, devWork->channelHi,
(long)devWork->collnet.count, devWork->collnet.chunkCount);
} else {
TRACE(NCCL_COLL, "Collective %s(%s, %s, %s, %s) count=%ld devFuncId=%d channel{Lo..Hi}={%d..%d} count{Lo,Mid,Hi}={%ld,%ld,%ld} chunkBytes{Lo,Mid,Hi}={%d,%d,%d}",
ncclFuncToString(task->func), ncclDevRedOpToString(task->opDev.op),
ncclDatatypeToString(task->datatype), ncclAlgoToString(task->algorithm),
ncclProtoToString(task->protocol),
(long)task->count, task->devFuncId, devWork->channelLo, devWork->channelHi,
(long)devWork->cbd.countLo, (long)devWork->cbd.countMid, (long)devWork->cbd.countHi,
int(devWork->cbd.chunkGrainsLo*ncclProtoGrainSize(task->protocol)),
int(devWork->cbd.chunkGrainsMid*ncclProtoGrainSize(task->protocol)),
int(devWork->cbd.chunkGrainsHi*ncclProtoGrainSize(task->protocol)));
}
}
for (int i=0; i < task->nCleanupQueueElts; i++) {
ncclIntruQueueEnqueue(&plan->cleanupQueue, ncclIntruQueueDequeue(&planner->collCleanupQueue));
}
ncclIntruQueueDequeue(&planner->collTaskQueue);
ncclIntruQueueDequeue(&planner->collWorkQueue);
nPlanColls -= 1;
planner->nTasksColl -= 1;
ncclIntruQueueEnqueue(&plan->collTaskQueue, task);
ncclIntruQueueEnqueue(&plan->workQueue, workNode);
plan->workBytes += workNode->size;
}
return ncclSuccess;
}
NCCL_PARAM(P2pLLThreshold, "P2P_LL_THRESHOLD", 16384);
NCCL_PARAM(ChunkSize, "CHUNK_SIZE", 0);
// Put p2p op in plan assuming there is sizeof(ncclDevWorkBatch) in batch budget
// and sizeof(ncclDevWorkP2p) in work budget. "sendRank" and "recvRank" must
// match the corresponding values for this round of the p2p schedule (no -1's).
// No-op's are encoded with a -1 size.
static ncclResult_t addP2pToPlan(
struct ncclComm* comm, struct ncclKernelPlan* plan,
int nChannelsMin, int nChannelsMax, int p2pRound,
int sendRank, void* sendAddr, ssize_t sendBytes,
int recvRank, void* recvAddr, ssize_t recvBytes,
struct ncclTaskP2p** p2pTasks
) {
constexpr int connIndex = 1;
bool selfSend = (sendRank == comm->rank);
// recv: dir=0, send: dir=1
void* addrs[2] = {recvAddr, sendAddr};
ssize_t bytes[2] = {recvBytes, sendBytes};
bool protoLL[2] = {!selfSend, !selfSend};
bool network[2] = {false, false};
bool proxySameProcess[2] = {true, true};
uint8_t base = ncclP2pChannelBaseForRound(comm, p2pRound);
if (!selfSend) {
for (int part=0; part < nChannelsMax; part++) {
int channelId = ncclP2pChannelForPart(comm->p2pnChannels, base, part);
struct ncclChannelPeer** channelPeers = comm->channels[channelId].peers;
for (int dir=0; dir <= 1; dir++) {
int peerRank = dir ? sendRank : recvRank;
struct ncclConnector* conn = dir ? &channelPeers[peerRank]->send[connIndex]
: &channelPeers[peerRank]->recv[connIndex];
protoLL[dir] &= conn->conn.buffs[NCCL_PROTO_LL] != nullptr;
network[dir] |= conn->transportComm == (dir ? &netTransport.send : &netTransport.recv);
proxySameProcess[dir] &= conn->proxyConn.sameProcess;
}
}
}
ssize_t thresholdLL = nChannelsMax*ncclParamP2pLLThreshold();
ssize_t paramChunkSize = ncclParamChunkSize();
// Arrays indexed by dir where recv=0, send=1:
int nChannels[2];
int protocol[2];
int stepSize[2];
int chunkSize[2];
int chunkDataSize[2];
int chunkDataSize_u32fp8[2];
bool registered[2] = {false, false};
bool ipcRegistered[2] = {false, false};
for (int dir=0; dir < 2; dir++) { // 0=recv, 1=send
if (bytes[dir] != -1) protoLL[dir] &= bytes[dir] <= thresholdLL;
protocol[dir] = protoLL[dir] ? NCCL_PROTO_LL : NCCL_PROTO_SIMPLE;
stepSize[dir] = comm->buffSizes[protocol[dir]]/NCCL_STEPS;
if (protocol[dir] == NCCL_PROTO_SIMPLE) stepSize[dir] = comm->p2pChunkSize;
chunkSize[dir] = stepSize[dir];
if (paramChunkSize != 0) {
chunkSize[dir] = paramChunkSize;
} else if (network[dir]) {
// Tune chunk size for the network
if (protocol[dir] == NCCL_PROTO_SIMPLE && bytes[dir] < stepSize[dir]) chunkSize[dir] /= 4;
else if (bytes[dir] < 8*stepSize[dir]) chunkSize[dir] /= 2;
}