add some debug flags for communicator

paddle/fluid/operators/distributed/communicator.cc

@@ -30,7 +30,11 @@ DEFINE_bool(communicator_independent_recv_thread, true,
 DEFINE_int32(communicator_send_queue_size, 20,
              "queue size to recv gradient before send");
 DEFINE_int32(communicator_recv_wait_ms, 200, "wait time between each recv");
-DEFINE_int32(communicator_thread_pool_size, 5, "wait time between each recv");
+DEFINE_int32(communicator_thread_pool_size, 5, "thread num to do send or recv");
+DEFINE_int32(communicator_max_merge_var_num, 20,
+             "max var num to merge and send");
+DEFINE_bool(communicator_fake_rpc, false,
+            "fake mode does not really send any thing");
 
 namespace paddle {
 namespace operators {
@@ -92,6 +96,9 @@ Communicator::Communicator(const RpcCtxMap &send_varname_to_ctx,
   VLOG(0) << "communicator_recv_wait_ms: " << FLAGS_communicator_recv_wait_ms;
   VLOG(0) << "communicator_thread_pool_size: "
           << FLAGS_communicator_thread_pool_size;
+  VLOG(0) << "communicator_max_merge_var_num"
+          << FLAGS_communicator_max_merge_var_num;
+  VLOG(0) << "communicator_fake_rpc: " << FLAGS_communicator_fake_rpc;
   send_scope_.reset(new Scope());
   for (auto &iter : send_varname_to_ctx_) {
     send_varname_to_queue_[iter.first] =
@@ -123,17 +130,18 @@ void Communicator::SendThread() {
         auto send_task = [this, &var_name, &var_queue] {
           VLOG(3) << "merge var " << var_name << " and send";
           std::vector<std::shared_ptr<Variable>> vars;
-          // TODO(qiao): need to be configurable
-          const size_t max_merge_var_num = 20;
           size_t merged_var_num = 0;
-          while (var_queue->Size() > 0 && merged_var_num < max_merge_var_num) {
+          while (var_queue->Size() > 0 &&
+                 merged_var_num < FLAGS_communicator_max_merge_var_num) {
             vars.push_back(var_queue->Pop());
             merged_var_num++;
           }
           MergeVars(var_name, vars, send_scope_.get());
           auto send_functor = distributed::ParameterSend<float>();
           auto &ctx = send_varname_to_ctx_.at(var_name);
+          if (!FLAGS_communicator_fake_rpc) {
             send_functor(ctx, *send_scope_, true);
+          }
         };
         task_futures.emplace_back(
             send_threadpool_->enqueue(std::move(send_task)));
@@ -160,7 +168,9 @@ void Communicator::RecvAll() {
       auto &var_name = iter.first;
       VLOG(3) << "recv var " << var_name;
       auto recv_functor = distributed::ParameterRecv<float>();
+      if (!FLAGS_communicator_fake_rpc) {
         recv_functor(iter.second, *recv_scope_);
+      }
     };
     task_futures.emplace_back(recv_threadpool_->enqueue(std::move(recv_task)));
   }