Replace time.time() to time.perf_counter() for benchmarking. (#6178)

Signed-off-by: Lifu Huang <lifu.hlf@gmail.com>

benchmark/llm_judge/bench_sglang.py

@@ -59,7 +59,7 @@ def main(args):
     backend = select_sglang_backend(args)
 
     # Run requests
-    tic = time.time()
+    tic = time.perf_counter()
     states = multi_dimension_judge.run_batch(
         arguments,
         temperature=0,
@@ -67,7 +67,7 @@ def main(args):
         num_threads=args.parallel,
         progress_bar=True,
     )
-    latency = time.time() - tic
+    latency = time.perf_counter() - tic
 
     print(f"Latency: {latency:.3f}")