polish code test=develop

paddle/fluid/framework/details/build_strategy.cc

@@ -34,7 +34,7 @@ namespace details {
 static inline bool SeqOnlyAllReduceOps(const BuildStrategy &strategy) {
   // Should fix the allreduce op order if scheduling
   // them in multiple threads or processes to avoid hang.
-  // NOTE: ParallelExecutor would execute this pass on each graph, so
+  // NOTE: ParallelGraph would execute this pass on each graph, so
   // don't need to append it here.
   return (!strategy.enable_sequential_execution_ &&
           strategy.num_trainers_ > 1) &&

paddle/fluid/framework/details/multi_devices_graph_pass.cc

@@ -389,8 +389,8 @@ void MultiDevSSAGraphBuilderBase::CreateAllReduceOp(
   OpHandleBase *op_handle = nullptr;
 
   auto append_allreduce_op = [&](
-      std::vector<Scope *> &scopes,
-      std::vector<platform::Place> &places) -> OpHandleBase * {
+      const std::vector<Scope *> &scopes,
+      const std::vector<platform::Place> &places) -> OpHandleBase * {
 #if defined(PADDLE_WITH_CUDA) && !defined(_WIN32)
     result->Get<GraphOps>(kGraphOps).emplace_back(new AllReduceOpHandle(
         result->CreateEmptyNode("allreduce", ir::Node::Type::kOperation),
@@ -407,13 +407,11 @@ void MultiDevSSAGraphBuilderBase::CreateAllReduceOp(
     op_handle = append_allreduce_op(local_scopes_, places_);
 
   for (size_t i = 0; i < places_.size(); ++i) {
-    auto p = places_[i];
-    std::vector<Scope *> ss{local_scopes_[i]};
-    std::vector<platform::Place> ps{p};
-    if (strategy_.enable_parallel_graph_)
-      op_handle = append_allreduce_op(ss, ps);
+    if (strategy_.enable_parallel_graph_) {
+      op_handle = append_allreduce_op({local_scopes_[i]}, {places_[i]});
+    }
 
-    SetCommunicationContext(op_handle, p);
+    SetCommunicationContext(op_handle, places_[i]);
     auto &vars = result->Get<GraphVars>(kGraphVars)[i][og];
     PADDLE_ENFORCE(!vars.empty());
     auto &prev_grad = vars.back();
@@ -421,7 +419,7 @@ void MultiDevSSAGraphBuilderBase::CreateAllReduceOp(
 
     auto var =
         new VarHandle(result->CreateEmptyNode(og, ir::Node::Type::kVariable),
-                      vars.size(), i, og, p);
+                      vars.size(), i, og, places_[i]);
     vars.emplace_back(var);
     op_handle->AddOutput(var);
   }

paddle/fluid/framework/details/parallel_ssa_graph_executor.cc

@@ -32,8 +32,9 @@ ParallelSSAGraphExecutor::SeparateMultiDevicesGraph(
     g->Set(kGraphDepVars, new GraphDepVars);
     g->Set(kGraphOps, new GraphOps);
   }
+  auto op_handles = ir::FilterByNodeWrapper<OpHandleBase>(*graph);
 
-  for (auto &op : graph->Get<GraphOps>(kGraphOps)) {
+  for (auto &op : op_handles) {
     auto &dev_ctx = op->DeviceContext();
     auto &p = dev_ctx.begin()->first;
     int dev_id = boost::get<platform::CUDAPlace>(p).device;