Improve MFU metrics for prefill and verify timing (#29000)

Co-authored-by: Pranjal Shankhdhar <pranjal.ssh@gmail.com>

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

@@ -309,6 +309,11 @@ class EagerRunner(BaseRunner):
     ) -> Union[LogitsProcessorOutput, PPProxyTensors, EmbeddingPoolerOutput]:
         model_runner = self.model_runner
         kwargs = model_runner._extend_forward_kwargs(forward_batch, pp_proxy_tensors)
+        category = (
+            "target_verify"
+            if forward_batch.forward_mode.is_target_verify()
+            else "extend"
+        )
 
         if not model_runner.server_args.enable_pdmux:
             forward_batch = self.load_batch(forward_batch, pp_proxy_tensors)
@@ -337,7 +342,7 @@ class EagerRunner(BaseRunner):
             forward_positions = sharded_positions
 
         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()
         )