[XPU] Remove distributed_executor_backend check (#30760)

Signed-off-by: sihao.li <sihao.li@intel.com>
Co-authored-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/platforms/xpu.py

@@ -7,7 +7,6 @@ from typing import TYPE_CHECKING, Optional
 
 import torch
 
-import vllm.envs as envs
 from vllm.attention.backends.registry import AttentionBackendEnum
 from vllm.logger import init_logger
 
@@ -168,32 +167,6 @@ class XPUPlatform(Platform):
         if vllm_config.kv_transfer_config is not None:
             vllm_config.kv_transfer_config.enable_permute_local_kv = True
 
-        if parallel_config.distributed_executor_backend is None:
-            if parallel_config.world_size > 1:
-                parallel_config.distributed_executor_backend = "ray"
-            else:
-                parallel_config.distributed_executor_backend = "uni"
-        elif parallel_config.distributed_executor_backend == "mp":
-            # FIXME(kunshang):
-            # spawn needs calling `if __name__ == '__main__':`
-            # fork is not supported for xpu start new process.
-            if envs.VLLM_WORKER_MULTIPROC_METHOD != "spawn":
-                os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"
-                logger.warning(
-                    "Please use spawn as start method if you want to use mp."
-                )
-        elif (
-            parallel_config.distributed_executor_backend != "ray"
-            and parallel_config.distributed_executor_backend != "uni"
-            and parallel_config.distributed_executor_backend != "external_launcher"
-        ):
-            logger.warning(
-                "%s is not supported on XPU, fallback to ray distributed"
-                " executor backend.",
-                parallel_config.distributed_executor_backend,
-            )
-            parallel_config.distributed_executor_backend = "ray"
-
         if model_config and model_config.use_mla:
             logger.info(
                 "MLA is enabled on a non-GPU platform; forcing chunked "