[XPU] Fix MOE DP accuracy issue on XPU (vllm-project#25465)

Signed-off-by: xuebwang-amd <xuebwang@amd.com>

Author: faaany

examples/offline_inference/data_parallel.py

@@ -101,6 +101,13 @@ def parse_args():
         "--quantization",
         type=str,
     )
+    parser.add_argument(
+        "--disable-expert-parallel",
+        dest="enable_expert_parallel",
+        action="store_false",
+        help="Disable expert parallel (default: enabled).",
+    )
+    parser.set_defaults(enable_expert_parallel=True)
     return parser.parse_args()
 
 
@@ -113,6 +120,7 @@ def main(
     dp_master_port,
     GPUs_per_dp_rank,
     enforce_eager,
+    enable_expert_parallel,
     trust_remote_code,
     max_num_seqs,
     max_model_len,
@@ -168,7 +176,7 @@ def start(rank):
         model=model,
         tensor_parallel_size=GPUs_per_dp_rank,
         enforce_eager=enforce_eager,
-        enable_expert_parallel=True,
+        enable_expert_parallel=enable_expert_parallel,
         trust_remote_code=trust_remote_code,
         max_num_seqs=max_num_seqs,
         max_model_len=max_model_len,
@@ -229,6 +237,7 @@ def start(rank):
                 dp_master_port,
                 tp_size,
                 args.enforce_eager,
+                args.enable_expert_parallel,
                 args.trust_remote_code,
                 args.max_num_seqs,
                 args.max_model_len,

vllm/distributed/device_communicators/xpu_communicator.py

@@ -25,6 +25,12 @@ def __init__(self,
         super().__init__(cpu_group, device, device_group, unique_name)
         if self.use_all2all:
             all2all_backend = envs.VLLM_ALL2ALL_BACKEND
+            if all2all_backend != "naive":
+                logger.warning(
+                    "`%s` all2all manager is not supported on XPU."
+                    "Falling back to `naive` all2all manager for XPU.",
+                    all2all_backend)
+                all2all_backend = "naive"
             if all2all_backend == "naive":
                 from .all2all import NaiveAll2AllManager
                 self.all2all_manager = NaiveAll2AllManager(self.cpu_group)
@@ -67,3 +73,16 @@ def gather(self,
 
     def broadcast(self, input_: torch.Tensor, src: int = 0) -> None:
         dist.broadcast(input_, src=src, group=self.device_group)
+
+    def dispatch(
+            self, hidden_states: torch.Tensor,
+            router_logits: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
+        assert self.all2all_manager is not None
+        hidden_states, router_logits = self.all2all_manager.dispatch(
+            hidden_states, router_logits)
+        return hidden_states, router_logits
+
+    def combine(self, hidden_states: torch.Tensor) -> torch.Tensor:
+        assert self.all2all_manager is not None
+        hidden_states = self.all2all_manager.combine(hidden_states)
+        return hidden_states