!3257 [AutoParallel]Support_NCCL_SUB_GROUP

Merge pull request !3257 from lichen/AutoParallel_support_sub_nccl_group

mindspore/ccsrc/frontend/parallel/device_manager.cc

@@ -345,9 +345,6 @@ std::string DeviceManager::GenerateGroupNameByRanks(RankList ranks) {
 // name. Otherwise, let the pointer g point to that group.
 Group DeviceManager::CreateGroup(const std::string &group_name,
                                  const std::vector<mindspore::parallel::Device> &devices) {
-  if ((world_group() == NCCL_WORLD_GROUP) && (devices.size() != devices_.size())) {
-    MS_LOG(EXCEPTION) << "Do not support sub group for nccl";
-  }
   Group g;
   (void)gm_.CreateGroup(group_name, devices, &g);
   return g;

mindspore/ccsrc/frontend/parallel/group_manager.cc

@@ -74,7 +74,7 @@ Status GroupManager::CreateGroup(const std::string &group_name, const std::vecto
     (void)CommManager::GetInstance().GetRankSize(world_group_, &world_size);
   }
 
-  if ((world_group_ == NCCL_WORLD_GROUP) || (devices.size() == world_size)) {
+  if (devices.size() == world_size) {
     auto it = groups_.find(world_group_);
     if (it == groups_.end()) {
       (void)group->Init(world_group_, devices);