[Feature] add disable-custom-all-reduce (#1148)

Co-authored-by: chenxu02 <chenxu02@zhihu.com>
Co-authored-by: Yineng Zhang <me@zhyncs.com>

python/sglang/srt/model_executor/model_runner.py

@@ -37,6 +37,7 @@ from vllm.distributed import (
     get_tp_group,
     init_distributed_environment,
     initialize_model_parallel,
+    set_custom_all_reduce,
 )
 from vllm.distributed.parallel_state import in_the_same_node_as
 from vllm.model_executor.model_loader import get_model
@@ -105,6 +106,7 @@ class ModelRunner:
             nccl_init_method = f"tcp://{server_args.nccl_init_addr}"
         else:
             nccl_init_method = f"tcp://127.0.0.1:{self.nccl_port}"
+        set_custom_all_reduce(not server_args.disable_custom_all_reduce)
         init_distributed_environment(
             backend="nccl",
             world_size=self.tp_size,

python/sglang/srt/server_args.py

@@ -86,6 +86,7 @@ class ServerArgs:
     enable_mla: bool = False
     attention_reduce_in_fp32: bool = False
     efficient_weight_load: bool = False
+    disable_custom_all_reduce: bool = False
 
     # Distributed args
     nccl_init_addr: Optional[str] = None
@@ -428,6 +429,12 @@ class ServerArgs:
             action="store_true",
             help="Turn on memory efficient weight loading with quantization (quantize per layer during loading).",
         )
+        parser.add_argument(
+            "--disable-custom-all-reduce",
+            action="store_true",
+            default=False,
+            help="Disable the custom all-reduce kernel and fall back to NCCL.",
+        )
 
     @classmethod
     def from_cli_args(cls, args: argparse.Namespace):