From 1f53193a630bc3b6289154dd5f5334a45ddb9285 Mon Sep 17 00:00:00 2001
From: Yu Yang <yuyang18@baidu.com>
Date: Mon, 19 Mar 2018 19:22:03 +0800
Subject: [PATCH] Use atomic code

---
 paddle/fluid/framework/parallel_executor.cc | 13 ++++++-----
 paddle/fluid/framework/parallel_executor.h  | 25 +++------------------
 2 files changed, 10 insertions(+), 28 deletions(-)

diff --git a/paddle/fluid/framework/parallel_executor.cc b/paddle/fluid/framework/parallel_executor.cc
index 2fb274d3a56..fa6763b5b58 100644
--- a/paddle/fluid/framework/parallel_executor.cc
+++ b/paddle/fluid/framework/parallel_executor.cc
@@ -645,7 +645,7 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
   auto fetched_data = std::make_shared<FetchedData>(fetch_tensors.size());
   // Version --> VarHandle
   member_->exception_.reset();
-  std::unordered_map<VarHandleBase *, GuardedBool> pending_vars;
+  std::unordered_map<VarHandleBase *, std::atomic<bool>> pending_vars;
   std::unordered_map<OpHandle *, size_t> pending_ops;
   std::vector<DummyVarHandle> dummy_vars;
 
@@ -694,7 +694,7 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
     op->offset_ = i;
     op->local_scopes_ = &member_->local_scopes_;
     for (auto &p : member_->places_) {
-      op->dev_ctx_[p] = this->member_->GetNCCLCtx(p).ctx_.get();
+      op->dev_ctx_[p] = member_->GetNCCLCtx(p).ctx_.get();
     }
 
     for (auto *var : vars) {
@@ -718,7 +718,7 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
   while (!pending_vars.empty()) {
     VarHandleBase *ready_var = nullptr;
     for (auto &pair : pending_vars) {
-      if (pair.second) {
+      if (pair.second.load(std::memory_order_consume)) {
         ready_var = pair.first;
       }
     }
@@ -750,9 +750,10 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
 }
 
 void ParallelExecutor::RunOp(
-    std::unordered_map<VarHandleBase *, GuardedBool> &pending_vars,
+    std::unordered_map<VarHandleBase *, std::atomic<bool>> &pending_vars,
     OpHandle *op) const {
-  std::vector<GuardedBool *> *ready_buffer = new std::vector<GuardedBool *>();
+  std::vector<std::atomic<bool> *> *ready_buffer =
+      new std::vector<std::atomic<bool> *>();
   for (auto *var : op->outputs_) {
     ready_buffer->emplace_back(&pending_vars[var]);
   }
@@ -761,7 +762,7 @@ void ParallelExecutor::RunOp(
     try {
       op->Run();
       for (auto *ready : *ready_buffer) {
-        *ready = true;
+        ready->store(true, std::memory_order_release);
       }
       delete ready_buffer;
     } catch (platform::EnforceNotMet ex) {
diff --git a/paddle/fluid/framework/parallel_executor.h b/paddle/fluid/framework/parallel_executor.h
index 8fe93fb62e1..03bf60b8bc4 100644
--- a/paddle/fluid/framework/parallel_executor.h
+++ b/paddle/fluid/framework/parallel_executor.h
@@ -33,26 +33,6 @@ class VarHandle;
 class OpHandle;
 class VarHandleBase;
 
-struct GuardedBool {
- public:
-  GuardedBool() {}
-
-  operator bool() const {
-    std::lock_guard<std::mutex> g(mtx_);
-    return value_;
-  }
-
-  GuardedBool& operator=(bool o) {
-    std::lock_guard<std::mutex> g(mtx_);
-    value_ = o;
-    return *this;
-  }
-
- private:
-  mutable std::mutex mtx_;
-  bool value_;
-};
-
 class ParallelExecutor {
  public:
   explicit ParallelExecutor(const std::vector<platform::Place>& places,
@@ -81,8 +61,9 @@ class ParallelExecutor {
 
   void BuildNCCLCommunicator() const;
 
-  void RunOp(std::unordered_map<VarHandleBase*, GuardedBool>& pending_vars,
-             OpHandle* op) const;
+  void RunOp(
+      std::unordered_map<VarHandleBase*, std::atomic<bool>>& pending_vars,
+      OpHandle* op) const;
 
   void PolishGraphToSupportDataHarzaeds() const;
 };
-- 
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