Wait input when data transform

Author: reyoung

paddle/fluid/framework/data_device_transform.cc

@@ -25,6 +25,10 @@ void TransDataDevice(const Tensor &in, const platform::Place &dst_place,
       in.place().which(), dst_place.which(),
       "Currently, model parallelism is only supported between CPU and CUDA");
 
+  // NOTE(yy): TransDataDevice should wait for computation of input.
+  platform::DeviceContextPool::Instance().Get(in.place())->Wait();
+  platform::DeviceContextPool::Instance().Get(dst_place)->Wait();
+
   // FIXME(zcd): TransDataDevice is used to transform data from GPU to CPU and
   // the enforced checkings have been done in GetDeviceContext, so the
   // `dev_ctx->Wait()` is necessary. But `dev_ctx->Wait()` will make the program