[XPU]Bug fix for some unexpected error when use AgRs backend on XPU device. (#36593)

Signed-off-by: yisheng <yi.sheng@intel.com>

vllm/v1/worker/xpu_worker.py

@@ -85,6 +85,9 @@ class XPUWorker(Worker):
             current_platform.dist_backend,
         )
 
+        # global all_reduce needed for overall oneccl warm up
+        torch.distributed.all_reduce(torch.zeros(1).xpu())
+
         # Set random seed.
         set_random_seed(self.model_config.seed)