Add scheduler metrics extension hooks (#29207)

Co-authored-by: Yinghai Lu <yinghai@meta.com>

python/sglang/srt/model_executor/model_runner.py

@@ -3052,13 +3052,18 @@ class ModelRunner(ModelRunnerKVCacheMixin):
                 and self.prefill_cuda_graph_runner.can_run_graph(forward_batch)
                 and get_cp_strategy() is None
             ):
+                category = (
+                    "target_verify"
+                    if forward_batch.forward_mode.is_target_verify()
+                    else "extend"
+                )
                 # Prefill cuda graph (piecewise).
                 kwargs = self._extend_forward_kwargs(forward_batch, pp_proxy_tensors)
                 # TODO: device_timer.wrap is too broad here — it also includes
                 # load_batch time. Move timing into the prefill cuda graph runner
                 # to capture only the model.forward part.
                 ctx = (
-                    self.device_timer.wrap(metadata={"category": "extend"})
+                    self.device_timer.wrap(metadata={"category": category})
                     if self.device_timer
                     else contextlib.nullcontext()
                 )

python/sglang/srt/model_executor/runner/eager_runner.py

@@ -282,8 +282,13 @@ class EagerRunner(BaseRunner):
             kwargs["input_embeds"] = sharded_hidden_states
             forward_positions = sharded_positions
 
+        category = (
+            "target_verify"
+            if forward_batch.forward_mode.is_target_verify()
+            else "extend"
+        )
         ctx = (
-            model_runner.device_timer.wrap(metadata={"category": "extend"})
+            model_runner.device_timer.wrap(metadata={"category": category})
             if model_runner.device_timer
             else contextlib.nullcontext()
         )