Tiny add response length metrics (#649)

Co-authored-by: Zilin Zhu <zhuzilinallen@gmail.com>

Author: fzyzcjy

slime/ray/rollout.py

@@ -17,7 +17,7 @@
 from slime.utils.http_utils import find_available_port, get_host_info, init_http_client
 from slime.utils.iter_utils import group_by
 from slime.utils.metric_checker import MetricChecker
-from slime.utils.metric_utils import compute_pass_rate, dict_add_prefix
+from slime.utils.metric_utils import compute_pass_rate, compute_statistics, dict_add_prefix
 from slime.utils.misc import load_function
 from slime.utils.ray_utils import Box
 from slime.utils.types import Sample
@@ -492,6 +492,7 @@ def _log_rollout_data(rollout_id, args, samples, rollout_extra_metrics, rollout_
     if args.rollout_num_gpus:
         log_dict["perf/tokens_per_gpu_per_sec"] = sum(response_lengths) / rollout_time / args.rollout_num_gpus
     log_dict["perf/longest_sample_tokens_per_sec"] = max(response_lengths) / rollout_time
+    log_dict |= dict_add_prefix(compute_statistics(response_lengths), f"rollout/response_len/")
     log_dict |= _compute_zero_std_metrics(args, samples)
     log_dict |= _compute_spec_metrics(args, samples)
     log_dict |= dict_add_prefix(_compute_reward_cat_metrics(args, samples), f"rollout/")

slime/utils/metric_utils.py

@@ -53,6 +53,14 @@ def estimator(n, c, k):
     return np.array([estimator(int(n), int(c), k) for n, c in zip(num_samples, num_correct)])
 
 
+def compute_statistics(values: List[float]) -> Dict[str, float]:
+    values = np.array(values)
+    return {
+        "mean": np.mean(values).item(),
+        "median": np.median(values).item(),
+    }
+
+
 def compression_ratio(
     data: Union[str, bytes],
     *,