diff --git a/mace/core/mace.cc b/mace/core/mace.cc
index a0e685694ea376a31eedeab7954672bff2cb4310..de6c93534e08bbdbcb71429a5dcddf69c2d50f11 100644
--- a/mace/core/mace.cc
+++ b/mace/core/mace.cc
@@ -494,9 +494,11 @@ MaceEngine::MaceEngine(const NetDef *net_def, DeviceType device_type):
   net_ = std::move(CreateNet(*net_def, ws_.get(), device_type));
 }
 MaceEngine::~MaceEngine(){}
-const float *MaceEngine::Run(const float *input,
-                             const std::vector<index_t> &input_shape,
-                             std::vector<int64_t> &output_shape) {
+bool MaceEngine::Run(const float *input,
+                     const std::vector<index_t> &input_shape,
+                     float *output) {
+  MACE_CHECK(output != nullptr, "output ptr cannot be NULL");
+
   Tensor *input_tensor =
       ws_->CreateTensor("mace_input_node:0", GetDeviceAllocator(device_type_), DT_FLOAT);
   input_tensor->Resize(input_shape);
@@ -509,16 +511,18 @@ const float *MaceEngine::Run(const float *input,
     LOG(FATAL) << "Net run failed";
   }
   // save output
-  const Tensor *output = ws_->GetTensor("mace_output_node:0");
-
-  if (output != nullptr) {
-    Tensor::MappingGuard output_guard(output);
-    auto shape = output->shape();
-    output_shape.resize(shape.size());
-    std::copy(shape.begin(), shape.end(), output_shape.begin());
-    return output->data<float>();
+  const Tensor *output_tensor = ws_->GetTensor("mace_output_node:0");
+
+  if (output_tensor != nullptr) {
+    Tensor::MappingGuard output_guard(output_tensor);
+    auto shape = output_tensor->shape();
+    int64_t output_size = std::accumulate(shape.begin(), shape.end(), 1,
+                                          std::multiplies<int64_t>());
+    std::memcpy(output, output_tensor->data<float>(),
+                output_size * sizeof(float));
+    return true;
   } else {
-    return nullptr;
+    return false;
   }
 }
 
diff --git a/mace/core/public/mace.h b/mace/core/public/mace.h
index caf5b311b0dbbedd40797000362e7d0bd46776be..088d7f9cacde4e800e73f5ffd5cce91d18304e53 100644
--- a/mace/core/public/mace.h
+++ b/mace/core/public/mace.h
@@ -307,9 +307,9 @@ class MaceEngine {
  public:
   explicit MaceEngine(const NetDef *net_def, DeviceType device_type);
   ~MaceEngine();
-  const float *Run(const float *input,
-                   const std::vector<int64_t> &input_shape,
-                   std::vector<int64_t> &output_shape);
+  bool Run(const float *input,
+           const std::vector<int64_t> &input_shape,
+           float *output);
  private:
   DeviceType device_type_;
   std::unique_ptr<Workspace> ws_;
diff --git a/mace/examples/mace_run.cc b/mace/examples/mace_run.cc
index 3de72de9289a419b98f9122c0f196f2fdb101b75..cb8a97257836042a9cfea81f640971215d68d5ec 100644
--- a/mace/examples/mace_run.cc
+++ b/mace/examples/mace_run.cc
@@ -7,7 +7,8 @@
  * mace_run --model=mobi_mace.pb \
  *          --input=input_node  \
  *          --output=MobilenetV1/Logits/conv2d/convolution  \
- *          --input_shape=1,3,224,224   \
+ *          --input_shape=1,224,224,3   \
+ *          --output_shape=1,224,224,2   \
  *          --input_file=input_data \
  *          --output_file=mace.out  \
  *          --device=NEON
@@ -108,6 +109,7 @@ int main(int argc, char **argv) {
   string input_node;
   string output_node;
   string input_shape;
+  string output_shape;
   string input_file;
   string output_file;
   string device;
@@ -119,6 +121,7 @@ int main(int argc, char **argv) {
       Flag("input", &input_node, "input node"),
       Flag("output", &output_node, "output node"),
       Flag("input_shape", &input_shape, "input shape, separated by comma"),
+      Flag("output_shape", &output_shape, "output shape, separated by comma"),
       Flag("input_file", &input_file, "input file name"),
       Flag("output_file", &output_file, "output file name"),
       Flag("device", &device, "CPU/NEON"),
@@ -141,13 +144,16 @@ int main(int argc, char **argv) {
           << "input: " << input_node << std::endl
           << "output: " << output_node << std::endl
           << "input_shape: " << input_shape << std::endl
+          << "output_shape: " << output_shape << std::endl
           << "input_file: " << input_file << std::endl
           << "output_file: " << output_file << std::endl
           << "device: " << device << std::endl
           << "round: " << round << std::endl;
 
-  vector<int64_t> shape;
-  ParseShape(input_shape, &shape);
+  vector<int64_t> input_shape_vec;
+  vector<int64_t> output_shape_vec;
+  ParseShape(input_shape, &input_shape_vec);
+  ParseShape(output_shape, &output_shape_vec);
 
   // load model
   int64_t t0 = utils::NowMicros();
@@ -158,9 +164,12 @@ int main(int argc, char **argv) {
 
   DeviceType device_type = ParseDeviceType(device);
   VLOG(1) << "Device Type" << device_type;
-  int64_t input_size = std::accumulate(shape.begin(), shape.end(), 1,
-                                       std::multiplies<int64_t>());
+  int64_t input_size = std::accumulate(input_shape_vec.begin(),
+      input_shape_vec.end(), 1, std::multiplies<int64_t>());
+  int64_t output_size = std::accumulate(output_shape_vec.begin(),
+      output_shape_vec.end(), 1, std::multiplies<int64_t>());
   std::unique_ptr<float[]> input_data(new float[input_size]);
+  std::unique_ptr<float[]> output_data(new float[output_size]);
 
   // load input
   ifstream in_file(input_file, ios::in | ios::binary);
@@ -178,10 +187,9 @@ int main(int argc, char **argv) {
 
   LOG(INFO) << "Total init duration: " << init_micros << " us";
 
-  std::vector<int64_t> output_shape;
   VLOG(0) << "Warm up";
   t0 = utils::NowMicros();
-  engine.Run(input_data.get(), shape, output_shape);
+  engine.Run(input_data.get(), input_shape_vec, output_data.get());
   t1 = utils::NowMicros();
   LOG(INFO) << "1st warm up run duration: " << t1 - t0 << " us";
 
@@ -190,7 +198,7 @@ int main(int argc, char **argv) {
     t0 = utils::NowMicros();
     struct mallinfo prev = mallinfo();
     for (int i = 0; i < round; ++i) {
-      engine.Run(input_data.get(), shape, output_shape);
+      engine.Run(input_data.get(), input_shape_vec, output_data.get());
       if (malloc_check_cycle >= 1 && i % malloc_check_cycle == 0) {
         LOG(INFO) << "=== check malloc info change #" << i << " ===";
         prev = LogMallinfoChange(prev);
@@ -200,21 +208,12 @@ int main(int argc, char **argv) {
     LOG(INFO) << "Avg duration: " << (t1 - t0) / round << " us";
   }
 
-  const float *output = engine.Run(input_data.get(), shape, output_shape);
-  if (output != nullptr) {
+  MACE_CHECK(engine.Run(input_data.get(), input_shape_vec, output_data.get()));
+  if (output_data != nullptr) {
     ofstream out_file(output_file, ios::binary);
-    int64_t output_size =
-        std::accumulate(output_shape.begin(), output_shape.end(), 1,
-                        std::multiplies<int64_t>());
-    out_file.write((const char *)(output), output_size * sizeof(float));
+    out_file.write((const char *) (output_data.get()),
+                   output_size * sizeof(float));
     out_file.flush();
     out_file.close();
-    stringstream ss;
-    ss << "Output shape: [";
-    for (auto i : output_shape) {
-      ss << i << ", ";
-    }
-    ss << "]";
-    VLOG(0) << ss.str();
   }
 }
diff --git a/tools/validate_gcn.sh b/tools/validate_gcn.sh
index 645df8b586e255394900dbb6f6b5fa2b9e6f7675..a0f8e580ba174664e53dada6f9f0b83a3466c6d6 100644
--- a/tools/validate_gcn.sh
+++ b/tools/validate_gcn.sh
@@ -69,6 +69,7 @@ build_and_run()
     --input=mace_input_node \
     --output=mace_output_node \
     --input_shape="1,${IMAGE_SIZE},${IMAGE_SIZE},3"\
+    --output_shape="1,${IMAGE_SIZE},${IMAGE_SIZE},2"\
     --input_file=${PHONE_DATA_DIR}/${INPUT_FILE_NAME} \
     --output_file=${PHONE_DATA_DIR}/${OUTPUT_FILE_NAME} \
     --device=OPENCL   \