[lint] improve ruff check (#11922)

Co-authored-by: Xiaoyu Zhang <35585791+BBuf@users.noreply.github.com>

python/sglang/bench_one_batch_server.py

@@ -16,6 +16,7 @@ import argparse
 import dataclasses
 import itertools
 import json
+import logging
 import multiprocessing
 import os
 import random
@@ -39,6 +40,8 @@ from sglang.srt.server_args import ServerArgs
 from sglang.srt.utils import is_blackwell, kill_process_tree
 from sglang.test.test_utils import is_in_ci, write_github_step_summary
 
+logger = logging.getLogger(__name__)
+
 
 class ProfileLinks(BaseModel):
     """Pydantic model for profile trace links."""