diff --git a/paddle/fluid/framework/ir/graph_traits.h b/paddle/fluid/framework/ir/graph_traits.h
index edbe45acb98326ee3bf1d86495832ec8469b634e..f42bab20ed97e372d2da0c4a492a4458ab94e0a0 100644
--- a/paddle/fluid/framework/ir/graph_traits.h
+++ b/paddle/fluid/framework/ir/graph_traits.h
@@ -12,7 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#pragma once
+
 #include <stack>
+#include <vector>
+
 #include "paddle/fluid/framework/ir/graph.h"
 #include "paddle/fluid/framework/ir/node.h"
 
diff --git a/paddle/fluid/inference/analysis/CMakeLists.txt b/paddle/fluid/inference/analysis/CMakeLists.txt
index 27fe575cb6167a726ff92a8f3d2e47b6f536ba39..b972efe5b0a6942bf0710755bbabbaf863477931 100644
--- a/paddle/fluid/inference/analysis/CMakeLists.txt
+++ b/paddle/fluid/inference/analysis/CMakeLists.txt
@@ -8,7 +8,7 @@ cc_library(analysis SRCS pass_manager.cc dot.cc node.cc data_flow_graph.cc graph
   helper.cc
         model_store_pass.cc
   DEPS framework_proto proto_desc)
-cc_test(test_node SRCS node_tester.cc DEPS analysis)
+cc_test(test_node SRCS node_tester.cc DEPS analysis gflags glog gtest)
 cc_test(test_dot SRCS dot_tester.cc DEPS analysis)
 cc_binary(inference_analyzer SRCS analyzer_main.cc DEPS analysis)
 
diff --git a/paddle/fluid/inference/analysis/node.cc b/paddle/fluid/inference/analysis/node.cc
index f2e918f3ff41d9db0c3ec38561015967bed26f4e..3339b5044df0cf91d00aa9ddad310d4bf263bc3c 100644
--- a/paddle/fluid/inference/analysis/node.cc
+++ b/paddle/fluid/inference/analysis/node.cc
@@ -20,17 +20,6 @@ namespace paddle {
 namespace inference {
 namespace analysis {
 
-template <>
-std::string &NodeAttr::As<std::string>() {
-  if (data_.empty()) {
-    type_index_ = std::type_index(typeid(std::string));
-  }
-  PADDLE_ENFORCE_EQ(type_index_, std::type_index(typeid(std::string)));
-  return data_;
-}
-
-std::string &NodeAttr::String() { return As<std::string>(); }
-
 std::vector<Dot::Attr> Value::dot_attrs() const {
   return std::vector<Dot::Attr>({Dot::Attr("style", "filled,rounded"),
                                  Dot::Attr("shape", "box"),
diff --git a/paddle/fluid/inference/analysis/node.h b/paddle/fluid/inference/analysis/node.h
index 47e524bc5c4a6b1324d5f182053129311487522d..fb426fb893d12c017deda74fc05016053fbc6b1c 100644
--- a/paddle/fluid/inference/analysis/node.h
+++ b/paddle/fluid/inference/analysis/node.h
@@ -29,6 +29,7 @@ limitations under the License. */
 #include "paddle/fluid/inference/analysis/device.h"
 #include "paddle/fluid/inference/analysis/dot.h"
 #include "paddle/fluid/inference/analysis/helper.h"
+#include "paddle/fluid/platform/variant.h"
 
 namespace paddle {
 namespace inference {
@@ -38,39 +39,35 @@ class NodeMap;
 
 // A helper class to maintain the status from Pass.
 struct NodeAttr {
+  using any_t =
+      boost::variant<bool, float, int32_t, int64_t, void *, std::string>;
   // NOTE T should be a primary type or a struct combined by several primary
   // types.
   // NOTE the STL containers should not use here.
   // Some usages
   //   Attr attr;
   //   attr.Bool() = true;
-
   bool &Bool() { return As<bool>(); }
   float &Float() { return As<float>(); }
   int32_t &Int32() { return As<int32_t>(); }
   int64_t &Int64() { return As<int64_t>(); }
   void *&Pointer() { return As<void *>(); }
-  std::string &String();
+  std::string &String() { return As<std::string>(); }
 
  private:
   template <typename T>
   T &As() {
-    // init storage in the first usage.
-    if (data_.empty()) {
-      VLOG(4) << "resize data to " << sizeof(T);
-      type_index_ = std::type_index(typeid(T));
-      data_.resize(sizeof(T));
+    if (type_index_ == typeid(NodeAttr)) {
+      type_index_ = typeid(T);
+      any_data_ = T();
+    } else {
+      PADDLE_ENFORCE(type_index_ == typeid(T), "fetch error type");
     }
-    PADDLE_ENFORCE(framework::IsType<T>(type_index_),
-                   "type not matched, origin is %s, want %s",
-                   DataTypeNamer::Global().repr(type_index_),
-                   DataTypeNamer::Global().repr<T>());
-    PADDLE_ENFORCE_EQ(data_.size(), sizeof(T), "Node attr type recast error");
-    return *reinterpret_cast<T *>(&data_[0]);
+    return boost::get<T>(any_data_);
   }
 
  private:
-  std::string data_;
+  any_t any_data_;
   std::type_index type_index_{typeid(NodeAttr)};
 };
 
diff --git a/paddle/fluid/inference/analysis/node_tester.cc b/paddle/fluid/inference/analysis/node_tester.cc
index ea832a3a7e47758be9b6bd59a4325ddb576ec446..8bbcfff53741772ee3705e2efdf46a1b59ee02ab 100644
--- a/paddle/fluid/inference/analysis/node_tester.cc
+++ b/paddle/fluid/inference/analysis/node_tester.cc
@@ -20,6 +20,24 @@ namespace paddle {
 namespace inference {
 namespace analysis {
 
+TEST(NodeAttr, bool) {
+  NodeAttr x;
+  x.Bool() = true;
+  ASSERT_EQ(x.Bool(), true);
+}
+
+TEST(NodeAttr, int32) {
+  NodeAttr x;
+  x.Int32() = 32;
+  ASSERT_EQ(x.Int32(), 32);
+}
+
+TEST(NodeAttr, string) {
+  NodeAttr x;
+  x.String() = "Hello";
+  ASSERT_EQ(x.String(), "Hello");
+}
+
 TEST(Node, Attr) {
   // Node is an abstract class, use Value instead for they share the same Attr
   // logic.
@@ -27,6 +45,9 @@ TEST(Node, Attr) {
   auto* node = nodes.Create(Node::Type::kValue);
   node->attr("v0").Int32() = 2008;
   ASSERT_EQ(node->attr("v0").Int32(), 2008);
+
+  node->attr("str").String() = "hello world";
+  ASSERT_EQ(node->attr("str").String(), "hello world");
 }
 
 }  // namespace analysis
diff --git a/paddle/fluid/operators/recv_op.cc b/paddle/fluid/operators/recv_op.cc
index 4a6ce938a5f337d035b21f562d46daf606236db0..a1f368e8690512cec2db7593aabc0279bbe174eb 100644
--- a/paddle/fluid/operators/recv_op.cc
+++ b/paddle/fluid/operators/recv_op.cc
@@ -57,6 +57,8 @@ class RecvOp : public framework::OperatorBase {
 class RecvOpMaker : public framework::OpProtoAndCheckerMaker {
  public:
   void Make() {
+    AddInput("X", "(Any) Dummy inputs, used for control dependency")
+        .AsDuplicable();
     AddOutput("Out", "(Tensor) Variables to get from server.").AsDuplicable();
     AddComment(R"DOC(
 Recv operator
diff --git a/paddle/fluid/operators/send_barrier_op.cc b/paddle/fluid/operators/send_barrier_op.cc
index 1866a86048acbefadcb4d82cd6309cd16f0352d6..14b07649c416ff1b671fc9b5ee4eb956b44570c5 100644
--- a/paddle/fluid/operators/send_barrier_op.cc
+++ b/paddle/fluid/operators/send_barrier_op.cc
@@ -37,22 +37,19 @@ class SendBarrierOp : public framework::OperatorBase {
   void RunImpl(const framework::Scope& scope,
                const platform::Place& place) const override {
     std::vector<std::string> eps = Attr<std::vector<std::string>>("endpoints");
-    bool sync_mode = Attr<bool>("sync_mode");
 
     distributed::RPCClient* rpc_client =
         distributed::RPCClient::GetInstance<RPCCLIENT_T>();
 
-    VLOG(3) << "SendBarrierOp sync_mode:" << sync_mode;
+    VLOG(3) << "SendBarrierOp sync";
 
     // need to wait before sending send_barrier message
     PADDLE_ENFORCE(rpc_client->Wait(), "internal error in RPCClient");
-    if (sync_mode) {
-      for (auto& ep : eps) {
-        VLOG(3) << "send barrier, ep: " << ep;
-        rpc_client->AsyncSendBatchBarrier(ep);
-      }
-      PADDLE_ENFORCE(rpc_client->Wait(), "internal error in RPCClient");
+    for (auto& ep : eps) {
+      VLOG(3) << "send barrier, ep: " << ep;
+      rpc_client->AsyncSendBatchBarrier(ep);
     }
+    PADDLE_ENFORCE(rpc_client->Wait(), "internal error in RPCClient");
   }
 };
 
@@ -70,7 +67,6 @@ the Parameter Server would knew all variables have been sent.
                                       "(string vector, default 127.0.0.1:6164)"
                                       "Server endpoints to send variables to.")
         .SetDefault({"127.0.0.1:6164"});
-    AddAttr<bool>("sync_mode", "work in sync_mode or not").SetDefault(true);
   }
 };
 
diff --git a/paddle/fluid/operators/send_op.cc b/paddle/fluid/operators/send_op.cc
index 3cd42f2d059532b7090e66ce21de8e5cb014adf1..82a70e4bf13247d784371ffdf419c9f792d7f721 100644
--- a/paddle/fluid/operators/send_op.cc
+++ b/paddle/fluid/operators/send_op.cc
@@ -66,6 +66,8 @@ class SendOpMaker : public framework::OpProtoAndCheckerMaker {
   void Make() {
     AddInput("X", "(Tensor, SelectedRows) Input variables to be sent")
         .AsDuplicable();
+    AddOutput("Out", "(Any) Dummy outputs, used for control dependency")
+        .AsDuplicable();
     AddComment(R"DOC(
 Send operator
 
diff --git a/paddle/fluid/platform/cuda_device_function.h b/paddle/fluid/platform/cuda_device_function.h
index 23457ff5fe1ec27094113ba0dde26adc64c716b5..9f504d14a8da116648483c0f64cb511b46e6a97e 100644
--- a/paddle/fluid/platform/cuda_device_function.h
+++ b/paddle/fluid/platform/cuda_device_function.h
@@ -36,7 +36,7 @@ __forceinline__ __device__ T CudaShuffleDownSync(unsigned mask, T val,
 #if CUDA_VERSION < 9000
   return __shfl_down(val, delta, width);
 #else
-  return __shfl_down_sync(mask, val, delta, width);
+  return __shfl_down_sync(mask, val, static_cast<unsigned>(delta), width);
 #endif
 }
 
@@ -46,9 +46,16 @@ template <>
 __forceinline__ __device__ float16 CudaShuffleDownSync(unsigned mask,
                                                        float16 val, int delta,
                                                        int width) {
-  half tmp = static_cast<half>(val);
-  __shfl_down(tmp, static_cast<unsigned>(delta), width);
-  return float16(tmp);
+  return float16(
+      __shfl_down(static_cast<half>(val), static_cast<unsigned>(delta), width));
+}
+#else
+template <>
+__forceinline__ __device__ float16 CudaShuffleDownSync(unsigned mask,
+                                                       float16 val, int delta,
+                                                       int width) {
+  return float16(__shfl_down_sync(mask, static_cast<half>(val),
+                                  static_cast<unsigned>(delta), width));
 }
 #endif
 
diff --git a/paddle/fluid/platform/cuda_helper_test.cu b/paddle/fluid/platform/cuda_helper_test.cu
index ca5ca1caeb23f01c047feeccf9c276b2dcd1cb68..ee45afab93d079374aefe366425502890854c28d 100644
--- a/paddle/fluid/platform/cuda_helper_test.cu
+++ b/paddle/fluid/platform/cuda_helper_test.cu
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <gtest/gtest.h>
+#include <algorithm>
 #include <iostream>
 #include <random>
 
@@ -123,7 +124,7 @@ void TestUnalign(size_t num, const int shift_bit) {
   cudaMemcpy(out, d_in2, array_size, cudaMemcpyDeviceToHost);
   cudaDeviceSynchronize();
   for (size_t i = 0; i < num / 2; ++i) {
-    // NOTE(dzhwinter): the float16 add has small underflow/overflow
+    // NOTE(dzhwinter): the float16 add has small truncate error.
     // so we use EXPECT_NEAR to check the result.
     EXPECT_NEAR(static_cast<float>(out[i]),
                 static_cast<float>(AddFunctor<float16>()(r_in1[i], r_in2[i])),
@@ -151,3 +152,83 @@ TEST(CudaAtomic, float16Unalign) {
   TestUnalign(static_cast<size_t>(1024), /*shift_bit*/ 3);
   TestUnalign(static_cast<size_t>(1024 * 1024), /*shift_bit*/ 3);
 }
+
+// https://devblogs.nvidia.com/faster-parallel-reductions-kepler/
+template <typename T>
+static __forceinline__ __device__ T WarpReduceSum(T val) {
+  unsigned mask = 0u;
+  CREATE_SHFL_MASK(mask, true);
+  for (int offset = warpSize / 2; offset > 0; offset /= 2) {
+    val += paddle::platform::CudaShuffleDownSync(mask, val, offset);
+  }
+  return val;
+}
+
+template <typename T>
+__forceinline__ __device__ T BlockReduce(T val) {
+  static __shared__ T shared[32];  // Shared mem for 32 partial sums
+  int lane = threadIdx.x % warpSize;
+  int wid = threadIdx.x / warpSize;
+
+  val = WarpReduceSum(val);  // Each warp performs partial reduction
+
+  if (lane == 0) shared[wid] = val;  // Write reduced value to shared memory
+
+  __syncthreads();  // Wait for all partial reductions
+
+  // read from shared memory only if that warp existed
+  val =
+      (threadIdx.x < blockDim.x / warpSize) ? shared[lane] : static_cast<T>(0);
+
+  if (wid == 0) val = WarpReduceSum(val);  // Final reduce within first warp
+
+  return val;
+}
+
+template <typename T>
+__global__ void DeviceReduceSum(T* in, T* out, size_t N) {
+  T sum(0);
+  for (int i = blockIdx.x * blockDim.x + threadIdx.x; i < N;
+       i += blockDim.x * gridDim.x) {
+    sum += in[i];
+  }
+  sum = BlockReduce<T>(sum);
+  __syncthreads();
+  if (threadIdx.x == 0) out[blockIdx.x] = sum;
+}
+
+template <typename T>
+void TestReduce(size_t num, float atol = 0.01) {
+  T* in1;
+  T *d_in1, *d_in2;
+  size_t size = sizeof(T) * num;
+  cudaMalloc(reinterpret_cast<void**>(&d_in1), size);
+  cudaMalloc(reinterpret_cast<void**>(&d_in2), sizeof(T));
+  in1 = reinterpret_cast<T*>(malloc(size));
+  std::minstd_rand engine;
+  std::uniform_real_distribution<double> dist(0.0, 1.0);
+  for (size_t i = 0; i < num; ++i) {
+    in1[i] = static_cast<T>(dist(engine));
+  }
+  auto out = std::accumulate(in1, in1 + num, static_cast<T>(0));
+  cudaMemcpy(d_in1, in1, size, cudaMemcpyHostToDevice);
+  cudaDeviceSynchronize();
+  DeviceReduceSum<T><<<1, PADDLE_CUDA_NUM_THREADS>>>(d_in1, d_in2, num);
+  cudaMemcpy(in1, d_in2, sizeof(T), cudaMemcpyDeviceToHost);
+  cudaDeviceSynchronize();
+  // NOTE(dzhwinter): the float16 add has small underflow/overflow
+  // so we use EXPECT_NEAR to check the result.
+  EXPECT_NEAR(static_cast<float>(in1[0]), static_cast<float>(out), atol);
+  free(in1);
+  cudaFree(d_in1);
+  cudaFree(d_in2);
+}
+
+TEST(CudaShuffleSync, float16) {
+  TestReduce<float>(10);
+  TestReduce<float>(1000);
+
+  // float16 will overflow or accumulate truncate errors in big size.
+  TestReduce<float16>(10);
+  TestReduce<float16>(100, /*atol error*/ 1.0);
+}
diff --git a/paddle/scripts/submit_local.sh.in b/paddle/scripts/submit_local.sh.in
index 1283de9d957a46b848c7bb6caf9c5f49398468e2..622a2d51049d164b6e8423e4054081f40f190cb9 100755
--- a/paddle/scripts/submit_local.sh.in
+++ b/paddle/scripts/submit_local.sh.in
@@ -54,7 +54,7 @@ function cpu_config() {
   if [ $platform == "Linux" ]; then
     ht=`lscpu |grep "per core"|awk -F':' '{print $2}'|xargs`
   elif [ $platform == "Darwin" ]; then
-    if [`sysctl -n hw.physicalcpu` -eq `sysctl -n hw.logicalcpu`]; then
+    if [ `sysctl -n hw.physicalcpu` -eq `sysctl -n hw.logicalcpu` ]; then
       # HT is OFF
       ht=1
     fi
diff --git a/python/paddle/dataset/mnist.py b/python/paddle/dataset/mnist.py
index 3038747bf8d03cf82613f1b329b7eeb778a0b9f2..38addd0cfd9bd0afde7eefc57f2111b717b7e636 100644
--- a/python/paddle/dataset/mnist.py
+++ b/python/paddle/dataset/mnist.py
@@ -24,7 +24,6 @@ import paddle.dataset.common
 import subprocess
 import numpy
 import platform
-import six
 import tempfile
 from six.moves import range
 __all__ = ['train', 'test', 'convert']
diff --git a/python/paddle/fluid/layers/io.py b/python/paddle/fluid/layers/io.py
index 21a295a0982cbc51947a063beee542c13494024d..b03ee514f50f9a8c1425bd5b1d409b58ed62351a 100644
--- a/python/paddle/fluid/layers/io.py
+++ b/python/paddle/fluid/layers/io.py
@@ -24,7 +24,7 @@ from .layer_function_generator import templatedoc
 from .. import core
 from ..executor import global_scope
 from ..framework import convert_np_dtype_to_dtype_, default_main_program, \
-    default_startup_program, program_guard, Program
+    default_startup_program, program_guard, Program, Variable
 from ..layer_helper import LayerHelper
 from ..unique_name import generate as unique_name
 
@@ -209,7 +209,7 @@ class ListenAndServ(object):
             })
 
 
-def Send(endpoints, send_vars, sync=True):
+def Send(endpoints, send_vars, dummy_output=None, sync=True):
     """
     Send variables to the server side, and get vars from server
     side when server have finished running server side program.
@@ -223,6 +223,13 @@ def Send(endpoints, send_vars, sync=True):
     """
     assert (type(send_vars) == list)
 
+    if dummy_output is None:
+        dummy_output = []
+    elif isinstance(dummy_output, Variable):
+        dummy_output = [dummy_output]
+
+    assert (type(dummy_output) == list)
+
     epmap = endpoints.split(",")
     endpoints = list(set(epmap))
 
@@ -232,6 +239,7 @@ def Send(endpoints, send_vars, sync=True):
     helper.append_op(
         type="send",
         inputs={"X": send_vars},
+        outputs={"Out": dummy_output},
         attrs={
             "endpoints": endpoints,
             "epmap": epmap,
@@ -241,7 +249,7 @@ def Send(endpoints, send_vars, sync=True):
         helper.append_op(type="send_barrier", attrs={"endpoints": endpoints})
 
 
-def Recv(endpoints, get_vars, sync=True):
+def Recv(endpoints, get_vars, dummy_input=None, sync=True):
     """
     Receive variables from server side
 
@@ -256,13 +264,20 @@ def Recv(endpoints, get_vars, sync=True):
     """
     assert (type(get_vars) == list)
 
+    if dummy_input is None:
+        dummy_input = []
+    elif isinstance(dummy_input, Variable):
+        dummy_input = [dummy_input]
+
+    assert (type(dummy_input) == list)
+
     epmap = endpoints.split(",")
     endpoints = list(set(epmap))
 
     helper = LayerHelper("Recv", **locals())
     helper.append_op(
         type="recv",
-        inputs={"X": get_vars},
+        inputs={"X": dummy_input},
         outputs={"Out": get_vars},
         attrs={"endpoints": endpoints,
                "epmap": epmap})
diff --git a/python/paddle/fluid/tests/unittests/dist_se_resnext.py b/python/paddle/fluid/tests/unittests/dist_se_resnext.py
index b0ee6ff9f5941b090e663dac0122cfb575f2f442..1307ba4e4ad11ef01094c44068d916ff2d442f78 100644
--- a/python/paddle/fluid/tests/unittests/dist_se_resnext.py
+++ b/python/paddle/fluid/tests/unittests/dist_se_resnext.py
@@ -16,7 +16,6 @@ from __future__ import print_function
 
 import numpy as np
 import argparse
-import six
 import time
 import math
 
diff --git a/python/paddle/fluid/transpiler/distribute_transpiler.py b/python/paddle/fluid/transpiler/distribute_transpiler.py
index 49d1b6c7b4e8fe353a4e849a407bc988183c96eb..57bc2e8a0ba173bb1273a5183340d0b618f0d73c 100644
--- a/python/paddle/fluid/transpiler/distribute_transpiler.py
+++ b/python/paddle/fluid/transpiler/distribute_transpiler.py
@@ -34,6 +34,7 @@ import math
 import random
 import numpy as np
 import collections
+import six
 
 from .ps_dispatcher import RoundRobin, HashName, PSDispatcher
 from .. import core, framework
@@ -210,6 +211,9 @@ class DistributeTranspiler(object):
 
         ps_dispatcher = self.config.split_method(self.pserver_endpoints)
         self.has_distributed_lookup_table = self._has_distributed_lookup_table()
+        self.param_name_to_grad_name = dict()
+        for param_var, grad_var in self.params_grads:
+            self.param_name_to_grad_name[param_var.name] = grad_var.name
 
         # step 1: split and create vars, then put splited vars in dicts for later use.
         self._init_splited_vars()
@@ -229,34 +233,39 @@ class DistributeTranspiler(object):
             random.seed(self.origin_program.random_seed)
             random.shuffle(grad_var_mapping_items)
 
-        for orig_varname, splited_vars in grad_var_mapping_items:
+        grad_name_to_send_dummy_out = dict()
+        for grad_varname, splited_vars in grad_var_mapping_items:
             eplist = ps_dispatcher.dispatch(splited_vars)
 
             if not self.config.slice_var_up:
                 assert (len(splited_vars) == 1)
 
+            splited_grad_varname = grad_varname
             if len(splited_vars) == 1:
-                orig_varname = splited_vars[0].name
+                splited_grad_varname = splited_vars[0].name
                 index = find_op_by_output_arg(program.global_block(),
-                                              orig_varname)
+                                              splited_grad_varname)
             elif len(splited_vars) > 1:
-                orig_var = program.global_block().vars[orig_varname]
+                orig_var = program.global_block().vars[splited_grad_varname]
                 index = find_op_by_output_arg(program.global_block(),
-                                              orig_varname)
+                                              splited_grad_varname)
                 self._insert_split_op(program, orig_var, index, splited_vars)
                 index += 1
             else:
                 AssertionError("Can not insert the send op by original "
-                               "variable name :", orig_varname)
+                               "variable name :", splited_grad_varname)
 
+            dummy_output = program.global_block().create_var()
+            grad_name_to_send_dummy_out[grad_varname] = dummy_output
             program.global_block()._insert_op(
                 index=index + 1,
                 type="send",
                 inputs={"X": splited_vars},
-                outputs={},
+                outputs={"Out": dummy_output},
                 attrs={
                     "epmap": eplist,
-                    RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE
+                    RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE,
+                    "sync_mode": not self.sync_mode,
                 })
             for _, var in enumerate(splited_vars):
                 send_vars.append(var)
@@ -268,7 +277,6 @@ class DistributeTranspiler(object):
                 outputs={},
                 attrs={
                     "endpoints": pserver_endpoints,
-                    "sync_mode": self.sync_mode,
                     RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE
                 })
 
@@ -284,19 +292,21 @@ class DistributeTranspiler(object):
             self.param_grad_ep_mapping[ep]["grads"].append(send_vars[i])
 
         # step4: Concat the parameters splits together after recv.
-        for varname, splited_var in six.iteritems(self.param_var_mapping):
+        for param_varname, splited_var in six.iteritems(self.param_var_mapping):
             eps = []
             for var in splited_var:
                 index = [v.name for v in recv_vars].index(var.name)
                 eps.append(eplist[index])
-
+            grad_send_dummy_out = grad_name_to_send_dummy_out[
+                self.param_name_to_grad_name[param_varname]]
             program.global_block().append_op(
                 type="recv",
-                inputs={},
+                inputs={"X": [grad_send_dummy_out]},
                 outputs={"Out": splited_var},
                 attrs={
                     "epmap": eps,
-                    RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE
+                    RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE,
+                    "sync_mode": not self.sync_mode
                 })
 
         if self.sync_mode:
@@ -309,10 +319,10 @@ class DistributeTranspiler(object):
                     RPC_OP_ROLE_ATTR_NAME: RPC_OP_ROLE_ATTR_VALUE
                 })
 
-        for varname, splited_var in six.iteritems(self.param_var_mapping):
+        for param_varname, splited_var in six.iteritems(self.param_var_mapping):
             if len(splited_var) <= 1:
                 continue
-            orig_param = program.global_block().vars[varname]
+            orig_param = program.global_block().vars[param_varname]
             program.global_block().append_op(
                 type="concat",
                 inputs={"X": splited_var},
@@ -380,7 +390,7 @@ class DistributeTranspiler(object):
 
             op = startup_program.global_block().append_op(
                 type="recv",
-                inputs={},
+                inputs={"X": []},
                 outputs={"Out": splited_var},
                 attrs={
                     "epmap": eps,
@@ -786,19 +796,21 @@ class DistributeTranspiler(object):
                                           self.config.min_block_size)
         assert (len(grad_blocks) == len(param_blocks))
 
-        # origin_varname -> [splited_var]
+        # origin_param_name -> [splited_param_vars]
         self.param_var_mapping = self._create_vars_from_blocklist(
             self.origin_program, param_blocks)
+        # origin_grad_name -> [splited_grad_vars]
         self.grad_var_mapping = self._create_vars_from_blocklist(
             self.origin_program,
             grad_blocks,
             add_trainer_suffix=self.trainer_num > 1)
+        # dict(grad_splited_var -> param_splited_var)
         self.grad_param_mapping = collections.OrderedDict()
         for g, p in zip(grad_blocks, param_blocks):
             g_name, g_bid, _ = g.split(":")
             p_name, p_bid, _ = p.split(":")
             self.grad_param_mapping[self.grad_var_mapping[g_name][int(g_bid)]] =  \
-                    self.param_var_mapping[p_name][int(p_bid)]
+                self.param_var_mapping[p_name][int(p_bid)]
 
         # create mapping of endpoint -> split var to create pserver side program
         self.param_grad_ep_mapping = collections.OrderedDict()
@@ -919,7 +931,7 @@ class DistributeTranspiler(object):
                     index=op_index + 2,
                     type="send",
                     inputs={'X': self.trainer_side_table_grad_list},
-                    outputs={},
+                    outputs={'Out': []},
                     attrs={
                         "sync_mode": True,
                         "epmap": pserver_endpoints,
diff --git a/tools/manylinux1/Dockerfile.x64 b/tools/manylinux1/Dockerfile.x64
index 987fc01cfc13bcefbb9d792a6780fdfff158755d..0d59e4c110ff8502acb4dbcda15f855f7652a946 100644
--- a/tools/manylinux1/Dockerfile.x64
+++ b/tools/manylinux1/Dockerfile.x64
@@ -13,7 +13,7 @@ ENV PATH /opt/rh/devtoolset-2/root/usr/bin:$PATH
 ENV LD_LIBRARY_PATH /opt/rh/devtoolset-2/root/usr/lib64:/opt/rh/devtoolset-2/root/usr/lib:/usr/local/lib64:/usr/local/lib:${LD_LIBRARY_PATH}
 ENV PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
 
-RUN yum install -y sqlite-devel zlib-devel openssl-devel pcre-devel vim tk-devel tkinter libtool xz freetype-devel libpng-devel graphviz
+RUN yum install -y sqlite-devel zlib-devel openssl-devel pcre-devel vim tk-devel tkinter libtool xz graphviz
 COPY build_scripts /build_scripts
 RUN bash build_scripts/build.sh && \
   bash build_scripts/install_nccl2.sh && rm -r build_scripts
diff --git a/tools/manylinux1/build_scripts/build.sh b/tools/manylinux1/build_scripts/build.sh
index d99d3db2ed7e3a719f044d8117baeb7ac212b74d..eb4b477dcb538f7ba17cfc54057a97c9669a6916 100644
--- a/tools/manylinux1/build_scripts/build.sh
+++ b/tools/manylinux1/build_scripts/build.sh
@@ -28,7 +28,7 @@ AUTOCONF_HASH=954bd69b391edc12d6a4a51a2dd1476543da5c6bbf05a95b59dc0dd6fd4c2969
 PYTHON_COMPILE_DEPS="zlib-devel bzip2-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel"
 
 # Libraries that are allowed as part of the manylinux1 profile
-MANYLINUX1_DEPS="glibc-devel libstdc++-devel glib2-devel libX11-devel libXext-devel libXrender-devel  mesa-libGL-devel libICE-devel libSM-devel ncurses-devel"
+MANYLINUX1_DEPS="glibc-devel libstdc++-devel glib2-devel libX11-devel libXext-devel libXrender-devel  mesa-libGL-devel libICE-devel libSM-devel ncurses-devel freetype-devel libpng-devel"
 
 # Get build utilities
 MY_DIR=$(dirname "${BASH_SOURCE[0]}")