From 8dec4ad7a1c37b705b584e64c3eef4d6df320c13 Mon Sep 17 00:00:00 2001
From: Yu Yang <yuyang18@baidu.com>
Date: Wed, 21 Mar 2018 17:12:27 +0800
Subject: [PATCH] Use int not Place for vars

---
 paddle/fluid/framework/parallel_executor.cc | 46 ++++++++++-----------
 1 file changed, 21 insertions(+), 25 deletions(-)

diff --git a/paddle/fluid/framework/parallel_executor.cc b/paddle/fluid/framework/parallel_executor.cc
index 440040a2ef..d3919f0d51 100644
--- a/paddle/fluid/framework/parallel_executor.cc
+++ b/paddle/fluid/framework/parallel_executor.cc
@@ -28,6 +28,7 @@ limitations under the License. */
 namespace paddle {
 namespace framework {
 
+using details::ComputationOpHandle;
 using details::DummyVarHandle;
 using details::FetchOpHandle;
 using details::NCCLAllReduceOpHandle;
@@ -35,7 +36,6 @@ using details::OpHandleBase;
 using details::ScaleLossGradOpHandle;
 using details::VarHandle;
 using details::VarHandleBase;
-using details::ComputationOpHandle;
 
 class ParallelExecutorPrivate {
  public:
@@ -43,7 +43,9 @@ class ParallelExecutorPrivate {
                                    const std::vector<platform::Place> &places)
       : places_(places),
         fetch_dev_ctxs_(places),
-        pool_(num_threads <= 1 ? nullptr : new ThreadPool(num_threads)) {}
+        pool_(num_threads <= 1 ? nullptr : new ThreadPool(num_threads)) {
+    vars_.resize(places.size());
+  }
 
   std::vector<platform::Place> places_;
   platform::DeviceContextPool fetch_dev_ctxs_;
@@ -52,12 +54,7 @@ class ParallelExecutorPrivate {
 
   std::unique_ptr<platform::NCCLContextMap> nccl_ctxs_;
 
-  platform::Place main_place_;
-
-  std::unordered_map<platform::Place,
-                     std::unordered_map<std::string, std::map<int, VarHandle>>,
-                     platform::PlaceHash>
-      vars_;
+  std::vector<std::unordered_map<std::string, std::map<int, VarHandle>>> vars_;
 
   std::unordered_set<std::unique_ptr<VarHandleBase>> dep_vars_;
 
@@ -69,8 +66,8 @@ class ParallelExecutorPrivate {
   std::unique_ptr<platform::EnforceNotMet> exception_;
 
   VarHandle *GetVarHandle(const std::string &each_var_name,
-                          const platform::Place &place) {
-    auto &var_holders = vars_[place];
+                          const platform::Place &place, size_t place_offset) {
+    auto &var_holders = vars_[place_offset];
     auto &var_holder = var_holders[each_var_name];
     VarHandle *var = nullptr;
     if (var_holder.empty()) {
@@ -118,8 +115,8 @@ class ParallelExecutorPrivate {
   }
 
   void GenerateVar(OpHandleBase *op_handle, const std::string &each_var_name,
-                   const platform::Place &place) {
-    auto &vars = vars_[place][each_var_name];
+                   const platform::Place &place, size_t place_offset) {
+    auto &vars = vars_[place_offset][each_var_name];
     size_t version = vars.size();
     auto &var = vars[version];
     var.version_ = version;
@@ -144,11 +141,10 @@ ParallelExecutor::ParallelExecutor(
   for (size_t i = 0; i < member_->places_.size(); ++i) {
     member_->local_scopes_.push_back(&scope->NewScope());
   }
-  member_->main_place_ = places[0];
 
   // Bcast Parameters to all GPUs
   BuildNCCLCommunicator();
-  if (platform::is_gpu_place(member_->main_place_) &&
+  if (platform::is_gpu_place(places[0]) &&
       member_->local_scopes_.size() != 1) {  // Is CUDA
     BCastParamsToGPUs(startup_program);
   }
@@ -201,13 +197,13 @@ void ParallelExecutor::ConstructDependencyGraph(
       auto var_names = op->InputArgumentNames();
 
       for (auto &each_var_name : var_names) {
-        VarHandle *var = member_->GetVarHandle(each_var_name, p);
+        VarHandle *var = member_->GetVarHandle(each_var_name, p, i);
         op_handle->AddInput(var);
       }
       var_names = op->OutputArgumentNames();
 
       for (auto &each_var_name : var_names) {
-        member_->GenerateVar(op_handle, each_var_name, p);
+        member_->GenerateVar(op_handle, each_var_name, p, i);
       }
 
       if (is_forwarding) {
@@ -224,7 +220,7 @@ void ParallelExecutor::ConstructDependencyGraph(
           // loss->pending_ops_.emplace_back(op_handle);
           // op_handle->inputs_.emplace_back(loss);
 
-          member_->GenerateVar(op_handle, loss_var_name + "@GRAD", p);
+          member_->GenerateVar(op_handle, loss_var_name + "@GRAD", p, i);
           change_forward = true;
         }
       }
@@ -245,7 +241,7 @@ void ParallelExecutor::ConstructDependencyGraph(
 
           for (size_t i = 0; i < member_->places_.size(); ++i) {
             auto &p = member_->places_[i];
-            auto &vars = member_->vars_[p][og];
+            auto &vars = member_->vars_[i][og];
 
             if (vars.empty()) {  // This device has no data. continue.
               continue;
@@ -280,8 +276,8 @@ void ParallelExecutor::ConstructDependencyGraph(
  * https://en.wikipedia.org/wiki/Hazard_(computer_architecture)#Write_after_read_(WAR)
  */
 void ParallelExecutor::PolishGraphToSupportDataHazards() const {
-  for (auto &place_pair : member_->vars_) {
-    for (auto &name_pair : place_pair.second) {
+  for (auto &var_map : member_->vars_) {
+    for (auto &name_pair : var_map) {
       if (name_pair.second.size() <= 1) {
         return;
       }
@@ -369,8 +365,8 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
   std::unordered_map<OpHandleBase *, size_t> pending_ops;
   std::vector<DummyVarHandle> dummy_vars;
 
-  for (auto &place_pair : member_->vars_) {
-    for (auto &name_pair : place_pair.second) {
+  for (auto &var_map : member_->vars_) {
+    for (auto &name_pair : var_map) {
       for (auto &version_pair : name_pair.second) {
         pending_vars[&version_pair.second] =
             version_pair.second.generated_op_ == nullptr;
@@ -395,9 +391,9 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
   std::unordered_map<std::string, std::vector<VarHandleBase *>> fetched_vars;
 
   for (auto &fetch_var_name : fetch_tensors) {
-    for (auto &pair : member_->vars_) {
-      auto it = pair.second.find(fetch_var_name);
-      if (it != pair.second.end()) {
+    for (auto &var_map : member_->vars_) {
+      auto it = var_map.find(fetch_var_name);
+      if (it != var_map.end()) {
         fetched_vars[fetch_var_name].push_back(&it->second.rbegin()->second);
       }
     }
-- 
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