Add lock at building program function.

mace/core/net.cc

@@ -48,8 +48,6 @@ bool SimpleNet::Run(RunMetadata *run_metadata) {
       LOG(ERROR) << "Operator failed: " << ProtoDebugString(op->debug_def());
       return false;
     }
-    if (device_type_ == DeviceType::OPENCL)
-      OpenCLRuntime::Get()->command_queue().finish();
     if (op_stats) {
       op_stats->set_op_end_rel_micros(NowInMicroSec() -
                                       op_stats->all_start_micros());

mace/core/runtime/opencl/opencl_runtime.cc

@@ -104,9 +104,11 @@ cl::Device &OpenCLRuntime::device() { return device_; }
 cl::CommandQueue &OpenCLRuntime::command_queue() { return command_queue_; }
 
 cl::Program &OpenCLRuntime::program() {
-  // TODO(heliangliang) Support binary format
+  // TODO(liuqi) : useless, leave it for old code.
   return program_;
 }
+
+// TODO(heliangliang) Support binary format
 const std::map<std::string, std::string>
     OpenCLRuntime::program_map_ = {
   {"addn", "addn.cl"},
@@ -162,6 +164,7 @@ cl::Kernel OpenCLRuntime::BuildKernel(const std::string &program_name,
   }
   std::string built_program_key = program_name + build_options_str;
 
+  std::lock_guard<std::mutex> lock(program_build_mutex_);
   auto built_program_it = built_program_map_.find(built_program_key);
   cl::Program program;
   if (built_program_it != built_program_map_.end()) {

mace/core/runtime/opencl/opencl_runtime.h

@@ -45,6 +45,7 @@ class OpenCLRuntime {
   cl::Device device_;
   cl::CommandQueue command_queue_;
   cl::Program program_;
+  std::mutex program_build_mutex_;
   std::string kernel_path_;
   static const std::map<std::string,
                std::string> program_map_;