Tiny support customizing prometheus buckets for prefill delayer (#16831)

python/sglang/srt/metrics/collector.py

@@ -271,7 +271,7 @@ class SchedulerMetricsCollector:
         self,
         labels: Dict[str, str],
         enable_lora: bool = False,
-        prefill_delayer_max_delay_passes: int = 30,
+        server_args: Optional["ServerArgs"] = None,
     ) -> None:
         # We need to import prometheus_client after setting the env variable `PROMETHEUS_MULTIPROC_DIR`
         from prometheus_client import Counter, Gauge, Histogram, Summary
@@ -762,19 +762,36 @@ class SchedulerMetricsCollector:
             labelnames=list(labels.keys()) + ["category", "num_prefill_ranks"],
         )
 
+        max_delay = server_args.prefill_delayer_max_delay_passes
         self.prefill_delayer_wait_forward_passes = Histogram(
             name="sglang:prefill_delayer_wait_forward_passes",
             documentation="Histogram of forward passes waited by prefill delayer.",
             labelnames=labels.keys(),
-            # Need bucket "<=0" for zero-delay cases
-            buckets=[0, 5, 20, prefill_delayer_max_delay_passes - 1],
+            buckets=sorted(
+                set(
+                    x
+                    for x in (
+                        server_args.prefill_delayer_forward_passes_buckets
+                        or [5, 20, 50, 100, 200]
+                    )
+                    if x < max_delay
+                )
+                # Need bucket "<=0" for zero-delay cases, and "max_delay-1" to distinguish "max_delay" timeout passes
+                | {0, max_delay - 1}
+            ),
         )
         self.prefill_delayer_wait_seconds = Histogram(
             name="sglang:prefill_delayer_wait_seconds",
             documentation="Histogram of wait time in seconds by prefill delayer.",
             labelnames=labels.keys(),
-            # Need bucket "<=0" for zero-delay cases
-            buckets=[0, 5, 20, 100, 500],
+            buckets=sorted(
+                set(
+                    server_args.prefill_delayer_wait_seconds_buckets
+                    or [1, 2, 5, 10, 20, 50, 100, 200, 500]
+                )
+                # Need bucket "<=0" for zero-delay cases
+                | {0}
+            ),
         )
         self.prefill_delayer_outcomes_total = Counter(
             name="sglang:prefill_delayer_outcomes_total",