diff --git a/oneflow/core/comm_network/iocp/io_worker.cpp b/oneflow/core/comm_network/iocp/io_worker.cpp
index 83eea80bff80c468fca7e9d9a425728ffcd06e3d..02b58ebb7f8e8cb2a3ca44780a4c1e13afdd0168 100644
--- a/oneflow/core/comm_network/iocp/io_worker.cpp
+++ b/oneflow/core/comm_network/iocp/io_worker.cpp
@@ -108,13 +108,15 @@ void IOWorker::Start() {
 }
 
 void IOWorker::Stop() {
-  IOData* stop_io_data = new IOData;
-  stop_io_data->IO_type = IOType::kStop;
-  memset(&(stop_io_data->overlapped), 0, sizeof(OVERLAPPED));
-  ResetIODataBuff(stop_io_data);
-  PostQueuedCompletionStatus(completion_port_, 0,
-                             machine_id2socket_[this_machine_id_],
-                             reinterpret_cast<LPOVERLAPPED>(stop_io_data));
+  for (size_t i = 0; i < num_of_concurrent_threads_; ++i) {
+    IOData* stop_io_data = new IOData;
+    stop_io_data->IO_type = IOType::kStop;
+    memset(&(stop_io_data->overlapped), 0, sizeof(OVERLAPPED));
+    ResetIODataBuff(stop_io_data);
+    PostQueuedCompletionStatus(completion_port_, 0, i,
+                               reinterpret_cast<LPOVERLAPPED>(stop_io_data));
+    LOG(INFO) << "Post stop request " << i << " to IOCP\n";
+  }
 }
 
 void IOWorker::InitSockets() {
@@ -124,7 +126,6 @@ void IOWorker::InitSockets() {
   SOCKET listen_socket = socket(AF_INET, SOCK_STREAM, 0);
   PCHECK(listen_socket != INVALID_SOCKET)
       << "socket failed with error:" << WSAGetLastError() << "\n";
-  machine_id2socket_[this_machine_id_] = listen_socket;
   uint16_t this_listen_port = 1024;
   uint16_t listen_port_max = std::numeric_limits<uint16_t>::max();
   for (; this_listen_port < listen_port_max; ++this_listen_port) {
@@ -204,6 +205,7 @@ DWORD IOWorker::ThreadProc() {
     switch (io_data_ptr->IO_type) {
       case IOType::kStop: {
         delete io_data_ptr;
+        LOG(INFO) << "stop IOworker " << completion_key << " \n";
         return 0;
       }
       case IOType::kRecvMsgHead: {