[Feature] add multi-rank support for Lora (#4492)

Co-authored-by: rudy152 <czh1137892874@gmail.com>

python/sglang/bench_serving.py

@@ -965,7 +965,7 @@ async def benchmark(
     request_rate: float,
     max_concurrency: Optional[int],
     disable_tqdm: bool,
-    lora_name: str,
+    lora_names: List[str],
     extra_request_body: Dict[str, Any],
     profile: bool,
     pd_seperated: bool = False,
@@ -988,6 +988,11 @@ async def benchmark(
     # Warmup
     print("Starting initial single prompt test run...")
     test_prompt, test_prompt_len, test_output_len = input_requests[0]
+    if lora_names != None and len(lora_names) != 0:
+        lora_name = lora_names[0]
+    else:
+        lora_name = None
+
     test_input = RequestFuncInput(
         model=model_id,
         prompt=test_prompt,
@@ -1028,6 +1033,12 @@ async def benchmark(
     tasks: List[asyncio.Task] = []
     async for request in get_request(input_requests, request_rate):
         prompt, prompt_len, output_len = request
+        if lora_names != None and len(lora_names) != 0:
+            idx = random.randint(0, len(lora_names) - 1)
+            lora_name = lora_names[idx]
+        else:
+            lora_name = None
+
         request_func_input = RequestFuncInput(
             model=model_id,
             prompt=prompt,
@@ -1347,7 +1358,7 @@ def run_benchmark(args_: argparse.Namespace):
             request_rate=args.request_rate,
             max_concurrency=args.max_concurrency,
             disable_tqdm=args.disable_tqdm,
-            lora_name=args.lora_name,
+            lora_names=args.lora_name,
             extra_request_body=extra_request_body,
             profile=args.profile,
             pd_seperated=args.pd_seperated,
@@ -1366,6 +1377,13 @@ def set_ulimit(target_soft_limit=65535):
             print(f"Fail to set RLIMIT_NOFILE: {e}")
 
 
+class LoRAPathAction(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        setattr(namespace, self.dest, [])
+        for lora_name in values:
+            getattr(namespace, self.dest).append(lora_name)
+
+
 if __name__ == "__main__":
     parser = ArgumentParser(description="Benchmark the online serving throughput.")
     parser.add_argument(
@@ -1509,8 +1527,10 @@ if __name__ == "__main__":
     parser.add_argument(
         "--lora-name",
         type=str,
+        nargs="*",
         default=None,
-        help="The name of LoRA adapter",
+        action=LoRAPathAction,
+        help="The names of LoRA adapters. You can provide a list of names in the format {name} {name} {name}...",
     )
     parser.add_argument(
         "--prompt-suffix",