Add wait log

paddle/fluid/framework/parallel_executor.cc

@@ -146,6 +146,7 @@ struct ComputationOpHandle : public OpHandle {
     auto *cur_ctx = dev_ctx_[place_];
     for (auto *in : inputs_) {
       if (in->generated_op_ && in->generated_op_->dev_ctx_[place_] != cur_ctx) {
+        VLOG(3) << "Wait " << in->generated_op_->DebugString();
         in->generated_op_->Wait(cur_ctx);
       }
     }
@@ -163,13 +164,9 @@ struct ScaleLossGradOpHandle : public OpHandle {
                                  platform::Place place)
       : coeff_(static_cast<float>(1.0 / num_dev)),
         scope_(scope),
-        place_(place) {
-    cudaSetDevice(boost::get<platform::CUDAPlace>(place_).device);
-  }
+        place_(place) {}
 
-  ~ScaleLossGradOpHandle() {
-    cudaSetDevice(boost::get<platform::CUDAPlace>(place_).device);
-  }
+  ~ScaleLossGradOpHandle() {}
 
  protected:
   void RunImpl() override {