Merge pull request #14075 from sneaxiy/remove_some_locks_in_pe

Remove some locks in ParallelExecutor

paddle/fluid/framework/details/CMakeLists.txt

 cc_library(var_handle SRCS var_handle.cc DEPS place framework_proto node)
 cc_library(op_handle_base SRCS op_handle_base.cc DEPS var_handle device_context lod_tensor)
+cc_library(op_graph_view SRCS op_graph_view.cc DEPS op_handle_base)
 cc_library(scale_loss_grad_op_handle SRCS scale_loss_grad_op_handle.cc DEPS op_handle_base scope lod_tensor ddim memory)
 cc_library(fetch_op_handle SRCS fetch_op_handle.cc DEPS op_handle_base scope lod_tensor ddim memory)
 cc_library(computation_op_handle SRCS computation_op_handle.cc DEPS framework_proto scope place operator op_registry)
@@ -30,7 +31,9 @@ cc_library(data_balance_op_handle SRCS data_balance_op_handle.cc DEPS op_handle_
 cc_library(gather_op_handle SRCS gather_op_handle.cc DEPS op_handle_base scope ddim memory variable_visitor)
 cc_library(fuse_vars_op_handle SRCS fuse_vars_op_handle.cc DEPS op_handle_base scope)
 
-if(WITH_GPU)
+cc_library(modify_op_lock_and_record_event_pass SRCS modify_op_lock_and_record_event_pass.cc DEPS computation_op_handle op_graph_view multi_devices_helper)
+
+if (WITH_GPU)
   cc_library(reference_count_pass SRCS reference_count_pass.cc DEPS computation_op_handle scale_loss_grad_op_handle rpc_op_handle
           all_reduce_op_handle reduce_op_handle broadcast_op_handle data_balance_op_handle graph graph_helper pass)
 endif()
@@ -40,12 +43,13 @@ cc_library(sequential_execution_pass SRCS sequential_execution_pass.cc DEPS grap
 cc_library(multi_devices_graph_pass SRCS multi_devices_graph_pass.cc DEPS multi_devices_helper computation_op_handle
         scale_loss_grad_op_handle rpc_op_handle all_reduce_op_handle reduce_op_handle broadcast_op_handle data_balance_op_handle fused_broadcast_op_handle)
 
-if(WITH_GPU)
-  cc_library(ssa_graph_executor SRCS ssa_graph_executor.cc DEPS graph framework_proto reference_count_pass sequential_execution_pass)
-else()
-  cc_library(ssa_graph_executor SRCS ssa_graph_executor.cc DEPS graph framework_proto sequential_execution_pass)
+set(SSA_GRAPH_EXECUTOR_DEPS graph framework_proto sequential_execution_pass modify_op_lock_and_record_event_pass) 
+if (WITH_GPU)
+  list(APPEND SSA_GRAPH_EXECUTOR_DEPS reference_count_pass)
 endif()
 
+cc_library(ssa_graph_executor SRCS ssa_graph_executor.cc DEPS ${SSA_GRAPH_EXECUTOR_DEPS})
+
 cc_library(threaded_ssa_graph_executor SRCS threaded_ssa_graph_executor.cc DEPS fetch_op_handle ssa_graph_executor scope
         simple_threadpool device_context)
 

paddle/fluid/framework/details/build_strategy.cc

@@ -69,6 +69,10 @@ class ParallelExecutorPassBuilder : public ir::PassBuilder {
 
     // Verify that the graph is correct for multi-device executor.
     AppendPass("multi_devices_check_pass");
+
+    if (strategy_.remove_unnecessary_lock_) {
+      AppendPass("modify_op_lock_and_record_event_pass");
+    }
   }
 
  private:
@@ -136,3 +140,4 @@ USE_PASS(multi_devices_pass);
 USE_PASS(multi_devices_check_pass);
 USE_PASS(multi_devices_print_pass);
 USE_PASS(sequential_execution_pass);
+USE_PASS(modify_op_lock_and_record_event_pass);

paddle/fluid/framework/details/build_strategy.h

@@ -73,6 +73,8 @@ struct BuildStrategy {
 
   bool fuse_broadcast_op_{false};
 
+  bool remove_unnecessary_lock_{false};
+
   // User normally doesn't need to call this API.
   // The PassBuilder allows for more customized insert, remove of passes
   // from python side.

paddle/fluid/framework/details/computation_op_handle.cc

@@ -29,9 +29,15 @@ ComputationOpHandle::ComputationOpHandle(ir::Node *node, Scope *scope,
 void ComputationOpHandle::RunImpl() {
   WaitInputVarGenerated(place_);
 
-  this->RunAndRecordEvent([this] {
+  auto run_func = [this]() {
     op_->Run(*scope_->FindVar(kLocalExecScopeName)->Get<Scope *>(), place_);
-  });
+  };
+
+  if (is_lock_and_record_event_free_) {
+    run_func();
+  } else {
+    this->RunAndRecordEvent(run_func);
+  }
 }
 
 bool ComputationOpHandle::NeedWait(VarHandleBase *in_var) {

paddle/fluid/framework/details/computation_op_handle.h

@@ -36,6 +36,8 @@ struct ComputationOpHandle : public OpHandleBase {
 
   const platform::Place &GetPlace() const { return place_; }
 
+  void SetLockAndRecordEventFree(bool b) { is_lock_and_record_event_free_ = b; }
+
  protected:
   void RunImpl() override;
 
@@ -45,6 +47,7 @@ struct ComputationOpHandle : public OpHandleBase {
   std::unique_ptr<OperatorBase> op_;
   Scope *scope_;
   platform::Place place_;
+  bool is_lock_and_record_event_free_{false};
 };
 }  // namespace details
 }  // namespace framework

paddle/fluid/framework/details/modify_op_lock_and_record_event_pass.cc

+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/fluid/framework/details/modify_op_lock_and_record_event_pass.h"
+#include "paddle/fluid/framework/details/computation_op_handle.h"
+#include "paddle/fluid/framework/details/multi_devices_helper.h"
+#include "paddle/fluid/framework/details/op_graph_view.h"
+
+namespace paddle {
+namespace framework {
+namespace details {
+
+static bool IsLockAndRecordEventFreeComputationOpHandle(
+    ComputationOpHandle *op, const OpGraphView &graph_view) {
+  if (!platform::is_gpu_place(op->GetPlace())) return false;
+  for (auto &pending_op : graph_view.PendingOps(op)) {
+    auto *tmp = dynamic_cast<ComputationOpHandle *>(pending_op);
+    if (tmp == nullptr || !(tmp->GetPlace() == op->GetPlace())) {
+      return false;
+    }
+  }
+  return true;
+}
+
+std::unique_ptr<ir::Graph> ModifyOpLockAndRecordEventPass::ApplyImpl(
+    std::unique_ptr<ir::Graph> ir_graph) const {
+  auto &all_ops = ir_graph->Get<GraphOps>(kGraphOps);
+  OpGraphView graph_view(all_ops);
+  for (auto &op : all_ops) {
+    auto *compute_op = dynamic_cast<ComputationOpHandle *>(op.get());
+    if (compute_op == nullptr) continue;
+    bool is_lock_and_record_event_free =
+        IsLockAndRecordEventFreeComputationOpHandle(compute_op, graph_view);
+    compute_op->SetLockAndRecordEventFree(is_lock_and_record_event_free);
+    if (is_lock_and_record_event_free) {
+      VLOG(10) << "Set is_lock_and_record_event_free be true in op "
+               << compute_op->DebugString();
+    }
+  }
+  return ir_graph;
+}
+
+}  // namespace details
+}  // namespace framework
+}  // namespace paddle
+
+REGISTER_PASS(modify_op_lock_and_record_event_pass,
+              paddle::framework::details::ModifyOpLockAndRecordEventPass);

paddle/fluid/framework/details/modify_op_lock_and_record_event_pass.h

+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "paddle/fluid/framework/ir/graph.h"
+#include "paddle/fluid/framework/ir/pass.h"
+
+namespace paddle {
+namespace framework {
+namespace details {
+
+class ModifyOpLockAndRecordEventPass : public ir::Pass {
+ protected:
+  std::unique_ptr<ir::Graph> ApplyImpl(
+      std::unique_ptr<ir::Graph> graph) const override;
+};
+
+}  // namespace details
+}  // namespace framework
+}  // namespace paddle

paddle/fluid/framework/details/op_graph_view.cc

+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/fluid/framework/details/op_graph_view.h"
+#include <queue>
+#include <utility>
+
+namespace paddle {
+namespace framework {
+namespace details {
+
+OpGraphView::OpGraphView(
+    const std::vector<std::unique_ptr<OpHandleBase>> &ops) {
+  Build(ops);
+}
+
+void OpGraphView::Build(const std::vector<std::unique_ptr<OpHandleBase>> &ops) {
+  for (auto &op : ops) {
+    preceding_ops_[op.get()];
+    pending_ops_[op.get()];
+    for (auto &var : op->Outputs()) {
+      for (auto &pending_op : var->PendingOps()) {
+        preceding_ops_[pending_op].insert(op.get());
+        pending_ops_[op.get()].insert(pending_op);
+      }
+    }
+  }
+  PADDLE_ENFORCE(
+      preceding_ops_.size() == ops.size() && pending_ops_.size() == ops.size(),
+      "There are duplicate ops in graph.");
+}
+
+size_t OpGraphView::OpNumber() const { return preceding_ops_.size(); }
+
+std::unordered_set<OpHandleBase *> OpGraphView::AllOps() const {
+  std::unordered_set<OpHandleBase *> ret;
+  for (auto &pair : preceding_ops_) {
+    ret.insert(pair.first);
+  }
+  return ret;
+}
+
+bool OpGraphView::HasOp(OpHandleBase *op) const {
+  return preceding_ops_.count(op) != 0;
+}
+
+void OpGraphView::EnforceHasOp(OpHandleBase *op) const {
+  PADDLE_ENFORCE(HasOp(op), "Cannot find op %s in OpGraphView",
+                 op == nullptr ? "nullptr" : op->DebugString());
+}
+
+const std::unordered_set<OpHandleBase *> &OpGraphView::PrecedingOps(
+    OpHandleBase *op) const {
+  EnforceHasOp(op);
+  return preceding_ops_.at(op);
+}
+
+const std::unordered_set<OpHandleBase *> &OpGraphView::PendingOps(
+    OpHandleBase *op) const {
+  EnforceHasOp(op);
+  return pending_ops_.at(op);
+}
+
+}  // namespace details
+}  // namespace framework
+}  // namespace paddle

paddle/fluid/framework/details/op_graph_view.h

+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <memory>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+#include "paddle/fluid/framework/details/op_handle_base.h"
+
+namespace paddle {
+namespace framework {
+namespace details {
+
+class OpGraphView {
+ public:
+  explicit OpGraphView(const std::vector<std::unique_ptr<OpHandleBase>> &ops);
+
+  size_t OpNumber() const;
+
+  std::unordered_set<OpHandleBase *> AllOps() const;
+
+  const std::unordered_set<OpHandleBase *> &PrecedingOps(
+      OpHandleBase *op) const;
+
+  const std::unordered_set<OpHandleBase *> &PendingOps(OpHandleBase *op) const;
+
+  bool HasOp(OpHandleBase *op) const;
+
+ private:
+  void Build(const std::vector<std::unique_ptr<OpHandleBase>> &ops);
+  void EnforceHasOp(OpHandleBase *op) const;
+
+  std::unordered_map<OpHandleBase *, std::unordered_set<OpHandleBase *>>
+      preceding_ops_;
+  std::unordered_map<OpHandleBase *, std::unordered_set<OpHandleBase *>>
+      pending_ops_;
+};
+
+}  // namespace details
+}  // namespace framework
+}  // namespace paddle

paddle/fluid/framework/details/reference_count_op_handle.h

@@ -51,7 +51,7 @@ class ReferenceCountOpHandle : public OpHandleBase {
     dev_ctx_ = static_cast<platform::CUDADeviceContext *>(
         platform::DeviceContextPool::Instance().Get(place));
     if (IsStreamGarabageCollector()) {
-      PADDLE_ENFORCE(cudaSetDevice(place.device));
+      platform::SetDeviceId(place.device);
       PADDLE_ENFORCE(cudaEventCreateWithFlags(&event_, cudaEventDisableTiming));
     }
 
@@ -61,7 +61,7 @@ class ReferenceCountOpHandle : public OpHandleBase {
   ~ReferenceCountOpHandle() {
     if (IsStreamGarabageCollector()) {
       auto gpu_place = boost::get<platform::CUDAPlace>(dev_ctx_->GetPlace());
-      PADDLE_ENFORCE(cudaSetDevice(gpu_place.device));
+      platform::SetDeviceId(gpu_place.device);
       PADDLE_ENFORCE(cudaEventDestroy(event_));
     }
   }

paddle/fluid/framework/details/reference_count_pass.cc

@@ -43,6 +43,23 @@ static ComputationOpHandle *FindNextComputationOpHandle(VarHandle *var_in) {
   return nullptr;
 }
 
+static void AddDependencyBetween(OpHandleBase *in, OpHandleBase *out,
+                                 ir::Graph *graph) {
+  auto it = std::find_if(
+      in->Outputs().begin(), in->Outputs().end(), [](VarHandleBase *var) {
+        return dynamic_cast<DummyVarHandle *>(var) != nullptr;
+      });
+
+  if (it != in->Outputs().end()) {
+    out->AddInput(*it);
+  } else {
+    auto *dep_var = new DummyVarHandle(graph->CreateControlDepVar());
+    graph->Get<GraphDepVars>(kGraphDepVars).emplace(dep_var);
+    in->AddOutput(dep_var);
+    out->AddInput(dep_var);
+  }
+}
+
 std::unique_ptr<ir::Graph> ReferenceCountPass::ApplyImpl(
     std::unique_ptr<ir::Graph> graph) const {
   auto &ref_cnts = Get<DeviceReferenceCountMap>(kGlobalReferenceCount);
@@ -133,12 +150,7 @@ std::unique_ptr<ir::Graph> ReferenceCountPass::ApplyImpl(
             auto *ref_cnt_handle = new ReferenceCountOpHandle(
                 ref_cnt_node, next_compute_op->GetScope(), place, {var_name},
                 gcs[place.device].get(), cur_ref_cnts[place.device].get());
-            if (next_compute_op->Outputs().empty()) {
-              auto *dep_var = new DummyVarHandle(graph->CreateControlDepVar());
-              next_compute_op->AddOutput(dep_var);
-              graph->Get<GraphDepVars>(kGraphDepVars).emplace(dep_var);
-            }
-            ref_cnt_handle->AddInput(next_compute_op->Outputs().front());
+            AddDependencyBetween(next_compute_op, ref_cnt_handle, graph.get());
             compute_ref_cnt_map[next_compute_op].reset(ref_cnt_handle);
           }
         }
@@ -160,12 +172,7 @@ std::unique_ptr<ir::Graph> ReferenceCountPass::ApplyImpl(
     auto *ref_cnt_handle = new ReferenceCountOpHandle(
         ref_cnt_node, compute_op->GetScope(), place, in_var_names,
         gcs[place.device].get(), cur_ref_cnts[place.device].get());
-    if (compute_op->Outputs().empty()) {
-      auto *dep_var = new DummyVarHandle(graph->CreateControlDepVar());
-      compute_op->AddOutput(dep_var);
-      graph->Get<GraphDepVars>(kGraphDepVars).emplace(dep_var);
-    }
-    ref_cnt_handle->AddInput(compute_op->Outputs().front());
+    AddDependencyBetween(compute_op, ref_cnt_handle, graph.get());
     compute_ref_cnt_map[compute_op].reset(ref_cnt_handle);
   }
 

paddle/fluid/operators/conv_cudnn_op.cu.cc

@@ -160,6 +160,7 @@ class CUDNNConvOpKernel : public framework::OpKernel<T> {
 
     // ------------------- cudnn conv forward ---------------------
     ScalingParamType<T> alpha = 1.0f, beta = 0.0f;
+    auto workspace_handle = dev_ctx.cudnn_workspace_handle();
     for (int i = 0; i < groups; i++) {
       auto cudnn_func = [&](void* cudnn_workspace) {
         CUDNN_ENFORCE(platform::dynload::cudnnConvolutionForward(
@@ -168,7 +169,7 @@ class CUDNNConvOpKernel : public framework::OpKernel<T> {
             cudnn_conv_desc, algo, cudnn_workspace, workspace_size_in_bytes,
             &beta, cudnn_output_desc, output_data + i * group_offset_out));
       };
-      dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+      workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
     }
   }
 };
@@ -314,6 +315,7 @@ class CUDNNConvGradOpKernel : public framework::OpKernel<T> {
 
     // ------------------- cudnn conv backward data ---------------------
     ScalingParamType<T> alpha = 1.0f, beta = 0.0f;
+    auto workspace_handle = dev_ctx.cudnn_workspace_handle();
     if (input_grad) {
       T* input_grad_data = input_grad->mutable_data<T>(ctx.GetPlace());
       // Because beta is zero, it is unnecessary to reset input_grad.
@@ -327,7 +329,7 @@ class CUDNNConvGradOpKernel : public framework::OpKernel<T> {
               data_algo, cudnn_workspace, workspace_size_in_bytes, &beta,
               cudnn_input_desc, input_grad_data + i * group_offset_in));
         };
-        dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+        workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
       }
     }
     // ------------------- cudnn conv backward filter ---------------------
@@ -343,7 +345,7 @@ class CUDNNConvGradOpKernel : public framework::OpKernel<T> {
               filter_algo, cudnn_workspace, workspace_size_in_bytes, &beta,
               cudnn_filter_desc, filter_grad_data + i * group_offset_filter));
         };
-        dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+        workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
       }
     }
   }

paddle/fluid/operators/conv_transpose_cudnn_op.cu.cc

@@ -104,6 +104,7 @@ class CUDNNConvTransposeOpKernel : public framework::OpKernel<T> {
     int output_offset = output->numel() / output->dims()[0] / groups;
     int filter_offset = filter->numel() / groups;
     T alpha = 1.0f, beta = 0.0f;
+    auto workspace_handle = dev_ctx.cudnn_workspace_handle();
     for (int g = 0; g < groups; g++) {
       auto cudnn_func = [&](void* cudnn_workspace) {
         CUDNN_ENFORCE(platform::dynload::cudnnConvolutionBackwardData(
@@ -112,7 +113,7 @@ class CUDNNConvTransposeOpKernel : public framework::OpKernel<T> {
             algo, cudnn_workspace, workspace_size_in_bytes, &beta,
             cudnn_output_desc, output_data + output_offset * g));
       };
-      dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+      workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
     }
   }
 };
@@ -208,6 +209,7 @@ class CUDNNConvTransposeGradOpKernel : public framework::OpKernel<T> {
         output_grad->numel() / output_grad->dims()[0] / groups;
     int filter_offset = filter->numel() / groups;
     T alpha = 1.0f, beta = 0.0f;
+    auto workspace_handle = dev_ctx.cudnn_workspace_handle();
     if (input_grad) {
       T* input_grad_data = input_grad->mutable_data<T>(ctx.GetPlace());
       // Because beta is zero, it is unnecessary to reset input_grad.
@@ -220,7 +222,7 @@ class CUDNNConvTransposeGradOpKernel : public framework::OpKernel<T> {
               cudnn_workspace, workspace_size_in_bytes, &beta, cudnn_input_desc,
               input_grad_data + input_offset * g));
         };
-        dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+        workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
       }
     }
 
@@ -238,7 +240,7 @@ class CUDNNConvTransposeGradOpKernel : public framework::OpKernel<T> {
               cudnn_workspace, workspace_size_in_bytes, &beta,
               cudnn_filter_desc, filter_grad_data + filter_offset * g));
         };
-        dev_ctx.RunCudnnFuncWithWorkspace(cudnn_func, workspace_size_in_bytes);
+        workspace_handle.RunFunc(cudnn_func, workspace_size_in_bytes);
       }
     }
   }

paddle/fluid/platform/device_context.cc

@@ -153,34 +153,20 @@ class EigenCudaStreamDevice : public Eigen::StreamInterface {
   mutable unsigned int* semaphore_;
 };
 
-class CudnnHolder {
- public:
-  CudnnHolder(const cudaStream_t* stream, const CUDAPlace& place)
+CudnnHolder::CudnnHolder(const cudaStream_t* stream, const CUDAPlace& place)
     : workspace_(nullptr), workspace_len_(0), stream_(stream), place_(place) {
   PADDLE_ENFORCE(dynload::cudnnCreate(&cudnn_handle_));
   PADDLE_ENFORCE(dynload::cudnnSetStream(cudnn_handle_, *stream_));
-  }
-
-  cudnnHandle_t cudnn_handle() const { return cudnn_handle_; }
-
-  void RunFunc(const std::function<void(void*)>& cudnn_func,
-               size_t required_workspace_len) {
-    std::lock_guard<std::mutex> lock(mtx_);
-    if (required_workspace_len > workspace_len_) {
-      ReallocateWorkspace(required_workspace_len);
-    }
-    cudnn_func(workspace_);
-  }
+}
 
-  ~CudnnHolder() {
+CudnnHolder::~CudnnHolder() {
   PADDLE_ENFORCE(dynload::cudnnDestroy(cudnn_handle_));
   if (workspace_ != nullptr) {
     paddle::memory::Free(place_, workspace_);
   }
-  }
+}
 
- private:
-  void ReallocateWorkspace(size_t required_workspace_len) {
+void CudnnHolder::ReallocateWorkspace(size_t required_workspace_len) {
   if (required_workspace_len <= workspace_len_) {
     return;
   }
@@ -191,17 +177,7 @@ class CudnnHolder {
   }
   workspace_ = paddle::memory::Alloc(place_, required_workspace_len);
   workspace_len_ = required_workspace_len;
-  }
-
-  cudnnHandle_t cudnn_handle_;
-  void* workspace_;
-  size_t workspace_len_;
-
-  const cudaStream_t* stream_;  // not owned;
-  const CUDAPlace place_;
-
-  std::mutex mtx_;
-};
+}
 
 CUDADeviceContext::CUDADeviceContext(CUDAPlace place)
     : place_(place), cudnn_holder_(nullptr) {
@@ -269,9 +245,8 @@ cudnnHandle_t CUDADeviceContext::cudnn_handle() const {
   return cudnn_holder_->cudnn_handle();
 }
 
-void CUDADeviceContext::RunCudnnFuncWithWorkspace(
-    const std::function<void(void*)>& cudnn_func, size_t workspace_len) const {
-  cudnn_holder_->RunFunc(cudnn_func, workspace_len);
+CudnnWorkspaceHandle CUDADeviceContext::cudnn_workspace_handle() const {
+  return CudnnWorkspaceHandle(cudnn_holder_.get());
 }
 
 cudaStream_t CUDADeviceContext::stream() const { return stream_; }

paddle/fluid/platform/device_context.h

@@ -73,7 +73,60 @@ struct DefaultDeviceContextType<platform::CPUPlace> {
 #ifdef PADDLE_WITH_CUDA
 
 class EigenCudaStreamDevice;
-class CudnnHolder;
+class CudnnHolder {
+ public:
+  CudnnHolder(const cudaStream_t* stream, const CUDAPlace& place);
+  ~CudnnHolder();
+  cudnnHandle_t cudnn_handle() const { return cudnn_handle_; }
+
+ private:
+  friend class CudnnWorkspaceHandle;
+  void ReallocateWorkspace(size_t required_workspace_len);
+
+  template <typename Callback>
+  void RunFuncImpl(Callback&& cudnn_func, size_t required_workspace_len) {
+    if (required_workspace_len > workspace_len_) {
+      ReallocateWorkspace(required_workspace_len);
+    }
+    cudnn_func(workspace_);
+  }
+
+  std::mutex& Mutex() { return mtx_; }
+
+  cudnnHandle_t cudnn_handle_;
+  void* workspace_;
+  size_t workspace_len_;
+
+  const cudaStream_t* stream_;  // not owned;
+  const CUDAPlace place_;
+
+  std::mutex mtx_;
+};
+
+class CudnnWorkspaceHandle {
+ public:
+  /*! \brief The lock would not be acquired when constructor calls.
+   *  The lock would be acquired when RunFunc() is called first time. */
+  inline explicit CudnnWorkspaceHandle(CudnnHolder* holder) : holder_(holder) {}
+
+  /*! \brief Thread which call RunFunc() would acquire the lock first
+   *  before invoking cudnn functions. */
+  template <typename Callback>
+  inline void RunFunc(Callback&& cudnn_func, size_t required_workspace_len) {
+    if (!guard_) {
+      guard_.reset(new std::lock_guard<std::mutex>(holder_->Mutex()));
+    }
+    holder_->RunFuncImpl(std::forward<Callback>(cudnn_func),
+                         required_workspace_len);
+  }
+
+  CudnnWorkspaceHandle(CudnnWorkspaceHandle&&) = default;
+  CudnnWorkspaceHandle& operator=(CudnnWorkspaceHandle&&) = delete;
+
+ private:
+  CudnnHolder* holder_;  // not own
+  std::unique_ptr<std::lock_guard<std::mutex>> guard_;
+};
 
 class CUDADeviceContext : public DeviceContext {
  public:
@@ -101,10 +154,14 @@ class CUDADeviceContext : public DeviceContext {
   /*! \brief  Return cudnn  handle in the device context. */
   cudnnHandle_t cudnn_handle() const;
 
-  /*! \brief  Run a cudnn function with the workspace provided by
-   * CUDADeviceContext */
-  void RunCudnnFuncWithWorkspace(const std::function<void(void*)>& cudnn_func,
-                                 size_t workspace_len) const;
+  /*! \brief  Return a cudnn workspace handle to call multiple cudnn
+   *  functions without interrupting by other threads.
+   *  Once the first cudnn function is called by the handle, a lock
+   *  would be acquired to prevent other threads from accessing the
+   *  workspace. Once the handle is destructed, the lock would be released.
+   *  CudnnWorkspaceHandle is an RAII object to implement thread-safe
+   *  sequential cudnn function calls. */
+  CudnnWorkspaceHandle cudnn_workspace_handle() const;
 
   /*! \brief  Return cuda stream in the device context. */
   cudaStream_t stream() const;

paddle/fluid/pybind/pybind.cc

@@ -821,13 +821,24 @@ All parameter, weight, gradient are variables in Paddle.
           [](BuildStrategy &self, bool b) {
             self.enable_data_balance_ = b;
           })  // FIXME(chengudo): enable_data_balance seems not important
-      .def_property("enable_sequential_execution",
+      .def_property(
+          "enable_sequential_execution",
           [](const BuildStrategy &self) {
             return self.enable_sequential_execution_;
           },
           [](BuildStrategy &self, bool b) {
             self.enable_sequential_execution_ = b;
-                    })
+          },
+          R"DOC(The type is BOOL. If set True, the execution order of ops would be the same as what is in the program. Default False.)DOC")
+      .def_property(
+          "remove_unnecessary_lock",
+          [](const BuildStrategy &self) {
+            return self.remove_unnecessary_lock_;
+          },
+          [](BuildStrategy &self, bool b) {
+            self.remove_unnecessary_lock_ = b;
+          },
+          R"DOC(The type is BOOL. If set True, some locks in GPU ops would be released and ParallelExecutor would run faster. Default False.)DOC")
       .def_property(
           "fuse_elewise_add_act_ops",
           [](const BuildStrategy &self) {

python/paddle/fluid/tests/unittests/parallel_executor_test_base.py

@@ -18,6 +18,7 @@ import multiprocessing
 import os
 import unittest
 import paddle.fluid as fluid
+import paddle.fluid.core as core
 import time
 import numpy as np
 import math
@@ -82,6 +83,8 @@ class TestParallelExecutorBase(unittest.TestCase):
                 if use_reduce else fluid.BuildStrategy.ReduceStrategy.AllReduce
             build_strategy.fuse_elewise_add_act_ops = fuse_elewise_add_act_ops
             build_strategy.enable_sequential_execution = enable_sequential_execution
+            if use_cuda and core.is_compiled_with_cuda():
+                build_strategy.remove_unnecessary_lock = True
 
             if use_parallel_executor:
                 exe = fluid.ParallelExecutor(