Sylvain Jeaugey
920dbe5b35
Optimization for Tree allreduce on A100. Improve aggregation performance. Use shared buffers for inter-node send/recv. Add NVTX profiling hooks. Accelerate alltoall connections by merging communication for all channels. Add support for one hop communication through NVLink, for faster send/recv communication on cubemesh topologies like DGX-1. Improve alltoall scheduling to better balance intra/inter node communication. Increase send/recv parallelism by 8x, each warp sending or receiving to a different peer. Net: move to v4. Net: make flush operation asynchronous to accelerate alltoall. Net: define maximum number of requests. Fix hang when using LL128 protocol after 2^31 steps. Fix #379 : topology injection failing when using less GPUs than described in the XML. Fix #394 : protocol mismatch causing hangs or crashes when using one GPU per node.
20 lines
939 B
C++
20 lines
939 B
C++
/*************************************************************************
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* Copyright (c) 2015-2020, 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 "enqueue.h"
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#include "collectives.h"
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NCCL_API(ncclResult_t, ncclReduceScatter, const void* sendbuff, void* recvbuff, size_t recvcount,
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ncclDataType_t datatype, ncclRedOp_t op, ncclComm* comm, cudaStream_t stream);
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ncclResult_t ncclReduceScatter(const void* sendbuff, void* recvbuff, size_t recvcount,
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ncclDataType_t datatype, ncclRedOp_t op, ncclComm* comm, cudaStream_t stream) {
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NVTX3_FUNC_RANGE_IN(nccl_domain);
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struct ncclInfo info = { ncclFuncReduceScatter, "ReduceScatter",
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sendbuff, recvbuff, recvcount, datatype, op, 0, comm, stream, /* Args */
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REDUCESCATTER_CHUNKSTEPS, REDUCESCATTER_SLICESTEPS };
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return ncclEnqueueCheck(&info);
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}
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