From 2ecef6f2c5802886eb0c7de509b9875c0dd9b28e Mon Sep 17 00:00:00 2001
From: Megvii Engine Team <megengine@megvii.com>
Date: Thu, 13 Aug 2020 17:38:33 +0800
Subject: [PATCH] refactor(nccl): disable cudaStreamSync in nccl opr

GitOrigin-RevId: a2604c9d039c05240be86bcede641f8b730e980e
---
 src/nccl/communicator.cpp | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/src/nccl/communicator.cpp b/src/nccl/communicator.cpp
index 4a1b70d..3757c3c 100644
--- a/src/nccl/communicator.cpp
+++ b/src/nccl/communicator.cpp
@@ -55,7 +55,6 @@ Status NcclCommunicator::send(const void* sendbuff, size_t len, uint32_t rank,
     cudaStream_t stream = static_cast<CudaContext*>(ctx.get())->get_stream();
     // perform nccl send synchronously
     NCCL_CHECK(ncclSend(sendbuff, len, ncclChar, rank, m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -66,7 +65,6 @@ Status NcclCommunicator::recv(void* recvbuff, size_t len, uint32_t rank,
     cudaStream_t stream = static_cast<CudaContext*>(ctx.get())->get_stream();
     // perform nccl send synchronously
     NCCL_CHECK(ncclRecv(recvbuff, len, ncclChar, rank, m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -87,8 +85,6 @@ Status NcclCommunicator::scatter(const void* sendbuff, void* recvbuff,
     }
     NCCL_CHECK(ncclRecv(recvbuff, recvlen, nccl_dtype, root, m_comm, stream));
     ncclGroupEnd();
-    // cuda stream synchronize
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -109,8 +105,6 @@ Status NcclCommunicator::gather(const void* sendbuff, void* recvbuff,
     }
     NCCL_CHECK(ncclSend(sendbuff, sendlen, nccl_dtype, root, m_comm, stream));
     ncclGroupEnd();
-    // cuda stream synchronize
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -130,8 +124,6 @@ Status NcclCommunicator::all_to_all(const void* sendbuff, void* recvbuff,
         NCCL_CHECK(ncclRecv((void*)q, len, nccl_dtype, r, m_comm, stream));
     }
     ncclGroupEnd();
-    // cuda stream synchronize
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -143,7 +135,6 @@ Status NcclCommunicator::all_gather(const void* sendbuff, void* recvbuff, size_t
     // perform all gather synchronously
     NCCL_CHECK(ncclAllGather(sendbuff, recvbuff, sendlen, get_nccl_dtype(dtype),
             m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -155,7 +146,6 @@ Status NcclCommunicator::all_reduce(const void* sendbuff, void* recvbuff, size_t
     // perform all reduce synchronously
     NCCL_CHECK(ncclAllReduce(sendbuff, recvbuff, len, get_nccl_dtype(dtype),
             get_nccl_reduce_op(op), m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -167,7 +157,6 @@ Status NcclCommunicator::reduce_scatter(const void* sendbuff, void* recvbuff, si
     // perform reduce scatter synchronously
     NCCL_CHECK(ncclReduceScatter(sendbuff, recvbuff, recvlen, get_nccl_dtype(dtype),
             get_nccl_reduce_op(op), m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -179,7 +168,6 @@ Status NcclCommunicator::broadcast(const void* sendbuff, void* recvbuff, size_t
     // perform broadcast synchronously
     NCCL_CHECK(ncclBroadcast(sendbuff, recvbuff, len, get_nccl_dtype(dtype), root,
             m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
@@ -191,7 +179,6 @@ Status NcclCommunicator::reduce(const void* sendbuff, void* recvbuff, size_t len
     // perform reduce synchronously
     NCCL_CHECK(ncclReduce(sendbuff, recvbuff, len, get_nccl_dtype(dtype),
             get_nccl_reduce_op(op), root, m_comm, stream));
-    CUDA_CHECK(cudaStreamSynchronize(stream));
     return MEGRAY_OK;
 }
 
-- 
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