From 76b321872a0c449d4f082cf437672e1d9e7510cb Mon Sep 17 00:00:00 2001
From: Zeng Jinle <32832641+sneaxiy@users.noreply.github.com>
Date: Mon, 14 Oct 2019 09:40:04 +0800
Subject: [PATCH] fix cuda dev_ctx by event, test=develop (#20553)

---
 .../details/sparse_all_reduce_op_handle.cc    | 31 ++++++++++++++++---
 .../details/sparse_all_reduce_op_handle.h     |  2 ++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/paddle/fluid/framework/details/sparse_all_reduce_op_handle.cc b/paddle/fluid/framework/details/sparse_all_reduce_op_handle.cc
index 070a17a9de5..e69bda6fcf8 100644
--- a/paddle/fluid/framework/details/sparse_all_reduce_op_handle.cc
+++ b/paddle/fluid/framework/details/sparse_all_reduce_op_handle.cc
@@ -13,6 +13,7 @@
 // limitations under the License.
 #include "paddle/fluid/framework/details/sparse_all_reduce_op_handle.h"
 #include <algorithm>
+#include <utility>
 #include "dgc/dgc.h"
 #include "paddle/fluid/framework/details/container_cast.h"
 #include "paddle/fluid/framework/details/reduce_and_gather.h"
@@ -41,11 +42,30 @@ SparseAllReduceOpHandle::SparseAllReduceOpHandle(
   }
 }
 
+void SparseAllReduceOpHandle::WaitInputVarGenerated() {
+#ifdef PADDLE_WITH_CUDA
+  for (auto &p : dev_ctxes_) {
+    if (platform::is_gpu_place(p.first)) {
+      int dev_id = boost::get<platform::CUDAPlace>(p.first).device;
+      auto *compute_dev_ctx =
+          platform::DeviceContextPool::Instance().GetByPlace(
+              platform::CUDAPlace(dev_id));
+      auto *dev_ctx = static_cast<platform::CUDADeviceContext *>(p.second);
+      if (compute_dev_ctx->stream() != dev_ctx->stream()) {
+        auto &event = events_.at(dev_id);
+        PADDLE_ENFORCE_CUDA_SUCCESS(
+            cudaEventRecord(event, compute_dev_ctx->stream()));
+        PADDLE_ENFORCE_CUDA_SUCCESS(
+            cudaStreamWaitEvent(dev_ctx->stream(), event, 0));
+      }
+    }
+  }
+#endif
+}
+
 void SparseAllReduceOpHandle::RunImplEncoded() {
   platform::RecordEvent record_event(Name());
 
-  WaitInputVarGenerated();
-
   auto in_var_handles = DynamicCast<VarHandle>(this->Inputs());
   auto out_var_handles = DynamicCast<VarHandle>(this->Outputs());
   PADDLE_ENFORCE_EQ(
@@ -87,6 +107,8 @@ void SparseAllReduceOpHandle::RunImplEncoded() {
   PADDLE_ENFORCE(nranks_ > 1);
   std::vector<std::function<void()>> all_reduce_calls;
 
+  std::vector<memory::AllocationPtr> allocations;
+
   for (size_t i = 0; i < local_scopes_.size(); ++i) {
     auto &place = places_[i];
     auto &in = *ins[i];
@@ -104,7 +126,6 @@ void SparseAllReduceOpHandle::RunImplEncoded() {
     int dev_id = boost::get<platform::CUDAPlace>(place).device;
     auto *nccl_ctxs = nccl_ctxs_->GetRunEnvNCCLCtx(run_order_, false);
     auto &nccl_ctx = nccl_ctxs->at(dev_id);
-    auto *dev_ctx = nccl_ctxs->DevCtx(dev_id);
     auto stream = nccl_ctx.stream();
     auto comm = nccl_ctx.comm_;
 
@@ -112,8 +133,9 @@ void SparseAllReduceOpHandle::RunImplEncoded() {
     // dgc use ncclAllGather to get all the encoded data
     // so the buffer need nranks.
     int buf_size = nranks_ * encode_size;
-    auto tmp_ious_data = memory::Alloc(*dev_ctx, buf_size);
+    auto tmp_ious_data = memory::Alloc(place, buf_size);
     void *gather_buff = reinterpret_cast<void *>(tmp_ious_data->ptr());
+    allocations.emplace_back(std::move(tmp_ious_data));
 
     VLOG(10) << "in_numel:" << in_numel << ", out_numel:" << out_numel
              << ", nranks:" << nranks_ << ", gather_buf size:" << buf_size
@@ -126,6 +148,7 @@ void SparseAllReduceOpHandle::RunImplEncoded() {
     });
   }
 
+  WaitInputVarGenerated();
   NCCLAllReduceFunc(all_reduce_calls);
 }
 
diff --git a/paddle/fluid/framework/details/sparse_all_reduce_op_handle.h b/paddle/fluid/framework/details/sparse_all_reduce_op_handle.h
index 9802f8dba7e..d15814a2197 100644
--- a/paddle/fluid/framework/details/sparse_all_reduce_op_handle.h
+++ b/paddle/fluid/framework/details/sparse_all_reduce_op_handle.h
@@ -36,6 +36,8 @@ class SparseAllReduceOpHandle : public AllReduceOpHandle {
                           bool is_encoded = false, int nranks = -1);
   std::string Name() const override;
 
+  void WaitInputVarGenerated() override;
+
  protected:
   void RunImpl() override;
   int GetKValue(const std::string &grad_name);
-- 
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