[Bugfix] Get available quantization methods from quantization registry (#4098)

benchmarks/benchmark_throughput.py

@@ -10,6 +10,8 @@ from tqdm import tqdm
 from transformers import (AutoModelForCausalLM, AutoTokenizer,
                           PreTrainedTokenizerBase)
 
+from vllm.model_executor.layers.quantization import QUANTIZATION_METHODS
+
 
 def sample_requests(
     dataset_path: str,
@@ -267,7 +269,7 @@ if __name__ == "__main__":
     parser.add_argument("--tokenizer", type=str, default=None)
     parser.add_argument('--quantization',
                         '-q',
-                        choices=['awq', 'gptq', 'squeezellm', None],
+                        choices=[*QUANTIZATION_METHODS, None],
                         default=None)
     parser.add_argument("--tensor-parallel-size", "-tp", type=int, default=1)
     parser.add_argument("--n",