[Auto Sync] Update collector.py (20251014) (#11625)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Byron Hsu <byronhsu1230@gmail.com>

python/sglang/srt/metrics/collector.py

@@ -118,6 +118,7 @@ class SchedulerStats:
     num_running_reqs: int = 0
     num_used_tokens: int = 0
     token_usage: float = 0.0
+    pending_prealloc_token_usage: float = 0.0
     swa_token_usage: float = 0.0
     gen_throughput: float = 0.0
     num_queue_reqs: int = 0
@@ -177,6 +178,12 @@ class SchedulerMetricsCollector:
             labelnames=labels.keys(),
             multiprocess_mode="mostrecent",
         )
+        self.pending_prealloc_token_usage = Gauge(
+            name="sglang:pending_prealloc_token_usage",
+            documentation="The token usage for pending preallocated tokens (not preallocated yet).",
+            labelnames=labels.keys(),
+            multiprocess_mode="mostrecent",
+        )
         self.swa_token_usage = Gauge(
             name="sglang:swa_token_usage",
             documentation="The token usage for SWA layers.",
@@ -516,6 +523,9 @@ class SchedulerMetricsCollector:
         self._log_gauge(self.num_running_reqs, stats.num_running_reqs)
         self._log_gauge(self.num_used_tokens, stats.num_used_tokens)
         self._log_gauge(self.token_usage, stats.token_usage)
+        self._log_gauge(
+            self.pending_prealloc_token_usage, stats.pending_prealloc_token_usage
+        )
         self._log_gauge(self.swa_token_usage, stats.swa_token_usage)
         self._log_gauge(self.gen_throughput, stats.gen_throughput)
         self._log_gauge(self.num_queue_reqs, stats.num_queue_reqs)