diff --git a/core/general-server/op/general_response_op.cpp b/core/general-server/op/general_response_op.cpp
index 956a69e5e7f15386eeed85a5ae7e56e197a16b17..271278c9cad3445423c893cce0c95432261194f4 100644
--- a/core/general-server/op/general_response_op.cpp
+++ b/core/general-server/op/general_response_op.cpp
@@ -76,8 +76,9 @@ int GeneralResponseOp::inference() {
   Response *res = mutable_data<Response>();
 
   // to let the client know which server the current response comes from
-  VLOG(2) << "getpid: " << getpid();
-  res->set_server_pid(static_cast<int>(getpid()));
+  int server_pid = static_cast<int>(getpid());
+  VLOG(2) << "getpid: " << server_pid;
+  res->set_server_pid(server_pid);
 
   for (int i = 0; i < batch_size; ++i) {
     FetchInst *fetch_inst = res->add_insts();