diff --git a/vllm/benchmarks/serve.py b/vllm/benchmarks/serve.py
index ca8d218581e77..6d52b51a9fcd0 100644
--- a/vllm/benchmarks/serve.py
+++ b/vllm/benchmarks/serve.py
@@ -948,7 +948,10 @@ def add_cli_args(parser: argparse.ArgumentParser):
     )
 
 
-def main(args: argparse.Namespace):
+def main(args: argparse.Namespace) -> dict[str, Any]:
+    return asyncio.run(main_async(args))
+
+async def main_async(args: argparse.Namespace) -> dict[str, Any]:
     print(args)
     random.seed(args.seed)
     np.random.seed(args.seed)
@@ -1025,8 +1028,7 @@ def main(args: argparse.Namespace):
     gc.collect()
     gc.freeze()
 
-    benchmark_result = asyncio.run(
-        benchmark(
+    benchmark_result = await benchmark(
             endpoint_type=args.endpoint_type,
             api_url=api_url,
             base_url=base_url,
@@ -1052,62 +1054,62 @@ def main(args: argparse.Namespace):
             ramp_up_start_rps=args.ramp_up_start_rps,
             ramp_up_end_rps=args.ramp_up_end_rps,
             ready_check_timeout_sec=args.ready_check_timeout_sec,
-        ))
+        )
 
     # Save config and results to json
-    if args.save_result or args.append_result:
-        result_json: dict[str, Any] = {}
+    result_json: dict[str, Any] = {}
 
-        # Setup
-        current_dt = datetime.now().strftime("%Y%m%d-%H%M%S")
-        result_json["date"] = current_dt
-        result_json["endpoint_type"] = args.endpoint_type
-        result_json["label"] = label
-        result_json["model_id"] = model_id
-        result_json["tokenizer_id"] = tokenizer_id
-        result_json["num_prompts"] = args.num_prompts
+    # Setup
+    current_dt = datetime.now().strftime("%Y%m%d-%H%M%S")
+    result_json["date"] = current_dt
+    result_json["endpoint_type"] = args.endpoint_type
+    result_json["label"] = label
+    result_json["model_id"] = model_id
+    result_json["tokenizer_id"] = tokenizer_id
+    result_json["num_prompts"] = args.num_prompts
 
-        # Metadata
-        if args.metadata:
-            for item in args.metadata:
-                if "=" in item:
-                    kvstring = item.split("=")
-                    result_json[kvstring[0].strip()] = kvstring[1].strip()
-                else:
-                    raise ValueError(
-                        "Invalid metadata format. Please use KEY=VALUE format."
-                    )
+    # Metadata
+    if args.metadata:
+        for item in args.metadata:
+            if "=" in item:
+                kvstring = item.split("=")
+                result_json[kvstring[0].strip()] = kvstring[1].strip()
+            else:
+                raise ValueError(
+                    "Invalid metadata format. Please use KEY=VALUE format."
+                )
 
-        # Traffic
-        result_json["request_rate"] = (args.request_rate if args.request_rate
-                                       < float("inf") else "inf")
-        result_json["burstiness"] = args.burstiness
-        result_json["max_concurrency"] = args.max_concurrency
+    # Traffic
+    result_json["request_rate"] = (args.request_rate if args.request_rate
+                                    < float("inf") else "inf")
+    result_json["burstiness"] = args.burstiness
+    result_json["max_concurrency"] = args.max_concurrency
 
-        if args.ramp_up_strategy is not None:
-            result_json["ramp_up_strategy"] = args.ramp_up_strategy
-            result_json["ramp_up_start_rps"] = args.ramp_up_start_rps
-            result_json["ramp_up_end_rps"] = args.ramp_up_end_rps
+    if args.ramp_up_strategy is not None:
+        result_json["ramp_up_strategy"] = args.ramp_up_strategy
+        result_json["ramp_up_start_rps"] = args.ramp_up_start_rps
+        result_json["ramp_up_end_rps"] = args.ramp_up_end_rps
 
-        # Merge with benchmark result
-        result_json = {**result_json, **benchmark_result}
+    # Merge with benchmark result
+    result_json = {**result_json, **benchmark_result}
 
-        if not args.save_detailed:
-            # Remove fields with too many data points
-            for field in [
-                    "input_lens",
-                    "output_lens",
-                    "ttfts",
-                    "itls",
-                    "generated_texts",
-                    "errors",
-            ]:
-                if field in result_json:
-                    del result_json[field]
-                if field in benchmark_result:
-                    del benchmark_result[field]
+    if not args.save_detailed:
+        # Remove fields with too many data points
+        for field in [
+                "input_lens",
+                "output_lens",
+                "ttfts",
+                "itls",
+                "generated_texts",
+                "errors",
+        ]:
+            if field in result_json:
+                del result_json[field]
+            if field in benchmark_result:
+                del benchmark_result[field]
 
         # Save to file
+    if args.save_result or args.append_result:
         base_model_id = model_id.split("/")[-1]
         max_concurrency_str = (f"-concurrency{args.max_concurrency}"
                                if args.max_concurrency is not None else "")
@@ -1129,3 +1131,5 @@ def main(args: argparse.Namespace):
                 outfile.write("\n")
             json.dump(result_json, outfile)
         save_to_pytorch_benchmark_format(args, result_json, file_name)
+
+    return result_json
\ No newline at end of file