[Frontend] Add FlexibleArgumentParser to support both underscore and dash in names (#5718)

benchmarks/benchmark_throughput.py

@@ -12,6 +12,7 @@ from transformers import (AutoModelForCausalLM, AutoTokenizer,
 
 from vllm.engine.arg_utils import EngineArgs
 from vllm.model_executor.layers.quantization import QUANTIZATION_METHODS
+from vllm.utils import FlexibleArgumentParser
 
 
 def sample_requests(
@@ -261,7 +262,7 @@ def main(args: argparse.Namespace):
 
 
 if __name__ == "__main__":
-    parser = argparse.ArgumentParser(description="Benchmark the throughput.")
+    parser = FlexibleArgumentParser(description="Benchmark the throughput.")
     parser.add_argument("--backend",
                         type=str,
                         choices=["vllm", "hf", "mii"],