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/*************************************************************************
* Copyright (c) 2015-2020, NVIDIA CORPORATION. All rights reserved.
*
* See LICENSE.txt for license information
************************************************************************/
#include "devcomm.h"
#include "primitives.h"
#include "collectives.h"
template<class FUNC, typename T, int UNROLL>
class ncclFunction<ncclFuncSendRecv, NCCL_ALGO_RING, NCCL_PROTO_SIMPLE, FUNC, T, UNROLL> {
public:
__device__ void run(struct ncclWorkElem* firstArgs) {
struct ncclWorkElem* args = firstArgs;
int tid = threadIdx.x;
int group = 0;
for (int s=0; s<NCCL_MAX_WORK_ELEMENTS; s++) {
int nThreadsSegment = args->p2p.nThreads;
if (nThreadsSegment == 0) return; // Nothing else to do
int groupRecv = group;
group += 1;
int groupSend = group;
group += nThreadsSegment > 128 ? 2 : 1;
if (tid < nThreadsSegment) {
const int nThreads = nThreadsSegment > 128 ? nThreadsSegment-WARP_SIZE : nThreadsSegment;
// Compute pointers
const T* sendbuff = (const T*)args->sendbuff;
T* recvbuff = (T*)args->recvbuff;
const ssize_t sendCount = args->p2p.sendCount;
const ssize_t recvCount = args->p2p.recvCount;
const int delta = args->p2p.delta;
if (delta == 0) {
if (tid < nThreads && sendbuff != recvbuff) {
// local copy : ReduceOrCopyMulti takes an int as number of elements,
// so we split it in blocks of 1G elements.
int blockSize = 1<<30;
for (size_t offset=0; offset<sendCount; offset += blockSize) {
size_t remaining = sendCount - offset;
if (remaining < blockSize) blockSize = remaining;
ReduceOrCopyMulti<UNROLL, FUNC, T, 1, 1, 1, 1>(tid, nThreads, 1, &sendbuff, 1, &recvbuff, blockSize);
sendbuff += blockSize; recvbuff += blockSize;
}
}
} else {
struct ncclDevComm* comm = args->comm;
struct ncclChannel* channel = comm->channels+blockIdx.x;
const int stepSize = comm->buffSizes[NCCL_PROTO_SIMPLE]/(sizeof(T)*NCCL_STEPS);
const int chunkSize = stepSize/SENDRECV_SLICEFACTOR;
int nThreadsSplit = nThreads/2;
if ((tid < nThreadsSplit) && recvCount >= 0) {
int peer = (comm->rank-delta+comm->nRanks)%comm->nRanks;
int nt = nThreadsSplit;
ncclPrimitives<UNROLL, 1, 1, T, 1, 0, 1, FUNC>
prims(tid, nt, &peer, NULL, recvbuff, stepSize, channel, comm, ncclShmem->ptrs, groupRecv);
if (recvCount == 0) {
prims.recv(recvbuff, 0);
} else for (ssize_t offset = 0; offset < recvCount; offset += chunkSize) {
int realChunkSize = min(chunkSize, recvCount-offset);
ALIGN_SIZE(realChunkSize, nt*sizeof(uint64_t)/sizeof(T));
int nelem = min(realChunkSize, recvCount-offset);
prims.directRecv(recvbuff+offset, offset, nelem);
}
}
if ((tid >= nThreadsSplit) && sendCount >= 0) {
int peer = (comm->rank+delta)%comm->nRanks;
int nt = nThreads-nThreadsSplit;
ncclPrimitives<UNROLL, 1, 1, T, 0, 1, 1, FUNC>
prims(tid-nThreadsSplit, nt, NULL, &peer, recvbuff, stepSize, channel, comm, ncclShmem->ptrs, groupSend);
if (sendCount == 0) {
prims.send(sendbuff, 0);
} else for (ssize_t offset = 0; offset < sendCount; offset += chunkSize) {
int realChunkSize = min(chunkSize, sendCount-offset);
ALIGN_SIZE(realChunkSize, nt*sizeof(uint64_t)/sizeof(T));
int nelem = min(realChunkSize, sendCount-offset);
prims.directSend(sendbuff+offset, offset, nelem);
}
}
}
}
tid -= nThreadsSegment;
if (tid < 0) return;
args++;
}
}
};
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