[Benchmark] Update seed argument handling in benchmark_serving.py (#7356)

benchmarks/benchmark_serving.py

@@ -1123,6 +1123,8 @@ def save_to_pytorch_benchmark_format(args: argparse.Namespace, results: dict[str
 def main(args: argparse.Namespace):
     """Main entry point"""
     print(args)
+    if args.seed is not None:
+        print(f"Using random seed: {args.seed}")
         random.seed(args.seed)
         np.random.seed(args.seed)
 
@@ -1431,7 +1433,7 @@ if __name__ == "__main__":
         "bursty requests. A higher burstiness value (burstiness > 1) "
         "results in a more uniform arrival of requests.",
     )
-    parser.add_argument("--seed", type=int, default=0)
+    parser.add_argument("--seed", type=int, default=None)
     parser.add_argument(
         "--shuffle",
         action="store_true",