support 1 shot allreduce in 1-node and 2-node using mscclpp (#6277)

python/sglang/srt/model_executor/model_runner.py

@@ -35,6 +35,7 @@ from sglang.srt.distributed import (
     init_distributed_environment,
     initialize_model_parallel,
     set_custom_all_reduce,
+    set_mscclpp_all_reduce,
 )
 from sglang.srt.distributed.parallel_state import monkey_patch_vllm_parallel_state
 from sglang.srt.layers.attention.tbo_backend import TboAttnBackend
@@ -460,6 +461,7 @@ class ModelRunner:
         else:
             dist_init_method = f"tcp://127.0.0.1:{self.dist_port}"
         set_custom_all_reduce(not self.server_args.disable_custom_all_reduce)
+        set_mscclpp_all_reduce(self.server_args.enable_mscclpp)
 
         if not self.is_draft_worker:
             # Only initialize the distributed environment on the target model worker.