Raise error for data-parallel with benchmark_throughput

Author: kartikx

benchmarks/benchmark_throughput.py

@@ -520,6 +520,10 @@ def validate_args(args):
         raise ValueError(
             "Tokenizer must be the same as the model for MII backend.")
 
+    # --data-parallel is not supported currently.
+    # https://github.com/vllm-project/vllm/issues/16222
+    if args.data_parallel_size > 1:
+        raise ValueError("Data parallel is not supported currently.")
 
 if __name__ == "__main__":
     parser = FlexibleArgumentParser(description="Benchmark the throughput.")