[Misc] Optimize ray worker initialization time (vllm-project#11275)

Signed-off-by: Rui Qiao <ruisearch42@gmail.com>
Co-authored-by: Cody Yu <hao.yu.cody@gmail.com>

vllm/executor/ray_gpu_executor.py

@@ -123,6 +123,7 @@ def _init_workers_ray(self, placement_group: "PlacementGroup",
 
         # Create the workers.
         driver_ip = get_ip()
+        workers = []
         for bundle_id, bundle in enumerate(placement_group.bundle_specs):
             if not bundle.get("GPU", 0):
                 continue
@@ -138,20 +139,30 @@ def _init_workers_ray(self, placement_group: "PlacementGroup",
                 scheduling_strategy=scheduling_strategy,
                 **ray_remote_kwargs,
             )(RayWorkerWrapper).remote(vllm_config=self.vllm_config)
+            workers.append(worker)
 
-            if self.use_ray_spmd_worker:
-                self.workers.append(worker)
-            else:
-                worker_ip = ray.get(worker.get_node_ip.remote())
-                if worker_ip == driver_ip and self.driver_dummy_worker is None:
+        worker_ip_refs = [
+            worker.get_node_ip.remote()  # type: ignore[attr-defined]
+            for worker in workers
+        ]
+        worker_ips = ray.get(worker_ip_refs)
+
+        if not self.use_ray_spmd_worker:
+            for i in range(len(workers)):
+                worker = workers[i]
+                worker_ip = worker_ips[i]
+                if self.driver_dummy_worker is None and worker_ip == driver_ip:
                     # If the worker is on the same node as the driver, we use it
                     # as the resource holder for the driver process.
                     self.driver_dummy_worker = worker
                     self.driver_worker = RayWorkerWrapper(
                         vllm_config=self.vllm_config)
-                else:
-                    # Else, added to the list of workers.
-                    self.workers.append(worker)
+                    workers.pop(i)
+                    worker_ips.pop(i)
+                    self.workers = workers
+                    break
+        else:
+            self.workers = workers
 
         logger.debug("workers: %s", self.workers)
         logger.debug("driver_dummy_worker: %s", self.driver_dummy_worker)
@@ -161,14 +172,12 @@ def _init_workers_ray(self, placement_group: "PlacementGroup",
                 "adjusting the Ray placement group or running the driver on a "
                 "GPU node.")
 
-        worker_ips = [
-            ray.get(worker.get_node_ip.remote())  # type: ignore[attr-defined]
-            for worker in self.workers
-        ]
         ip_counts: Dict[str, int] = {}
         for ip in worker_ips:
             ip_counts[ip] = ip_counts.get(ip, 0) + 1
 
+        worker_to_ip = dict(zip(self.workers, worker_ips))
+
         def sort_by_driver_then_worker_ip(worker):
             """
             Sort the workers based on 3 properties:
@@ -179,7 +188,7 @@ def sort_by_driver_then_worker_ip(worker):
             3. Finally, if the work is on a node with smaller IP address, it
                 should be placed first.
             """
-            ip = ray.get(worker.get_node_ip.remote())
+            ip = worker_to_ip[worker]
             return (ip != driver_ip, ip_counts[ip], ip)
 
         # After sorting, the workers on the same node will be