From 41bfec8dbb03ccf5a040e2b64fd5564c00532632 Mon Sep 17 00:00:00 2001
From: WangXi <wangxi16@baidu.com>
Date: Mon, 26 Apr 2021 11:50:39 +0800
Subject: [PATCH] [HybridParallel] fix port reuse when create multi group
 (#31876)

---
 paddle/fluid/imperative/nccl_context.cc       | 22 +++++++++++++++----
 paddle/fluid/imperative/nccl_context.h        |  3 ++-
 .../imperative/tests/nccl_context_test.cc     |  7 +++++-
 .../operators/collective/c_gen_nccl_id_op.cc  |  5 +++--
 4 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/paddle/fluid/imperative/nccl_context.cc b/paddle/fluid/imperative/nccl_context.cc
index b91fc460781..9f036742f0f 100644
--- a/paddle/fluid/imperative/nccl_context.cc
+++ b/paddle/fluid/imperative/nccl_context.cc
@@ -35,7 +35,7 @@ namespace imperative {
 
 void NCCLParallelContext::BcastNCCLId(
     std::vector<ncclUniqueId> &nccl_ids,  // NOLINT
-    int root) {
+    int root, int server_fd) {
   if (strategy_.local_rank_ == root) {
     std::vector<std::string> other_trainers;
     for (auto &ep : strategy_.trainer_endpoints_) {
@@ -45,11 +45,14 @@ void NCCLParallelContext::BcastNCCLId(
     }
     platform::SendBroadCastCommID(other_trainers, &nccl_ids);
   } else {
-    platform::RecvBroadCastCommID(strategy_.current_endpoint_, &nccl_ids);
+    platform::RecvBroadCastCommID(server_fd, strategy_.current_endpoint_,
+                                  &nccl_ids);
   }
 }
 
 void NCCLParallelContext::Init() {
+  int server_fd = -1;
+
   std::vector<ncclUniqueId> nccl_ids;
   nccl_ids.resize(strategy_.nrings_);
 
@@ -58,8 +61,13 @@ void NCCLParallelContext::Init() {
     for (size_t i = 0; i < nccl_ids.size(); ++i) {
       platform::dynload::ncclGetUniqueId(&nccl_ids[i]);
     }
+  } else {
+    // FIXME(wangxi): gloo will use rank0 endpoint, so not create socket server
+    // on rank0.
+    server_fd = platform::SocketServer::GetInstance(strategy_.current_endpoint_)
+                    .socket();
   }
-  BcastNCCLId(nccl_ids, 0);
+  BcastNCCLId(nccl_ids, 0, server_fd);
 
   int gpu_id = BOOST_GET_CONST(platform::CUDAPlace, place_).device;
   for (int ring_id = 0; ring_id < strategy_.nrings_; ring_id++) {
@@ -80,14 +88,20 @@ void NCCLParallelContext::Init() {
 }
 
 void NCCLParallelContext::InitWithRingID(int ring_id) {
+  int server_fd = -1;
   std::vector<ncclUniqueId> nccl_ids;
   nccl_ids.resize(1);
 
   if (strategy_.local_rank_ == 0) {
     // generate the unique ncclid on the root worker
     platform::dynload::ncclGetUniqueId(&nccl_ids[0]);
+  } else {
+    // FIXME(wangxi): gloo will use rank0 endpoint, so not create socket server
+    // on rank0.
+    server_fd = platform::SocketServer::GetInstance(strategy_.current_endpoint_)
+                    .socket();
   }
-  BcastNCCLId(nccl_ids, 0);
+  BcastNCCLId(nccl_ids, 0, server_fd);
 
   int gpu_id = BOOST_GET_CONST(platform::CUDAPlace, place_).device;
   VLOG(0) << "init nccl context nranks: " << strategy_.nranks_
diff --git a/paddle/fluid/imperative/nccl_context.h b/paddle/fluid/imperative/nccl_context.h
index bcaeb811b10..1eee393aa71 100644
--- a/paddle/fluid/imperative/nccl_context.h
+++ b/paddle/fluid/imperative/nccl_context.h
@@ -49,7 +49,8 @@ class NCCLParallelContext : public ParallelContext {
 
   ~NCCLParallelContext() override = default;
 
-  void BcastNCCLId(std::vector<ncclUniqueId>& nccl_ids, int root);  // NOLINT
+  void BcastNCCLId(std::vector<ncclUniqueId>& nccl_ids, int root,  // NOLINT
+                   int server_fd);
 
   void Init() override;
 
diff --git a/paddle/fluid/imperative/tests/nccl_context_test.cc b/paddle/fluid/imperative/tests/nccl_context_test.cc
index 4967df5341d..2d8a08217b0 100644
--- a/paddle/fluid/imperative/tests/nccl_context_test.cc
+++ b/paddle/fluid/imperative/tests/nccl_context_test.cc
@@ -15,6 +15,7 @@
 #include <thread>  // NOLINT
 
 #include "paddle/fluid/imperative/nccl_context.h"
+#include "paddle/fluid/platform/gen_comm_id_helper.h"
 
 #include "gtest/gtest.h"
 
@@ -36,9 +37,13 @@ imperative::ParallelStrategy GetStrategy(int local_rank) {
 #if defined(PADDLE_WITH_NCCL) || defined(PADDLE_WITH_RCCL)
 void BcastNCCLId(int local_rank, std::vector<ncclUniqueId>* nccl_ids) {
   auto strategy = GetStrategy(local_rank);
+  int server_fd = platform::CreateListenSocket(strategy.current_endpoint_);
+
   platform::CUDAPlace gpu(local_rank);
   imperative::NCCLParallelContext ctx(strategy, gpu);
-  ctx.BcastNCCLId(*nccl_ids, 0);
+  ctx.BcastNCCLId(*nccl_ids, 0, server_fd);
+
+  platform::CloseSocket(server_fd);
 }
 
 TEST(BcastNCCLId, Run) {
diff --git a/paddle/fluid/operators/collective/c_gen_nccl_id_op.cc b/paddle/fluid/operators/collective/c_gen_nccl_id_op.cc
index 7da30f64d1c..470537582e9 100644
--- a/paddle/fluid/operators/collective/c_gen_nccl_id_op.cc
+++ b/paddle/fluid/operators/collective/c_gen_nccl_id_op.cc
@@ -66,6 +66,9 @@ class CGenNCCLIdOp : public framework::OperatorBase {
       return Output("Out");
     };
 
+    std::string endpoint = Attr<std::string>("endpoint");
+    int server_fd = platform::SocketServer::GetInstance(endpoint).socket();
+
     std::vector<ncclUniqueId> nccl_ids;
     nccl_ids.resize(1);
 
@@ -75,8 +78,6 @@ class CGenNCCLIdOp : public framework::OperatorBase {
           Attr<std::vector<std::string>>("other_endpoints");
       platform::SendBroadCastCommID(endpoint_list, &nccl_ids);
     } else {
-      std::string endpoint = Attr<std::string>("endpoint");
-      int server_fd = platform::SocketServer::GetInstance(endpoint).socket();
       platform::RecvBroadCastCommID(server_fd, endpoint, &nccl_ids);
     }
 
-- 
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