[V1][Metrics] Add several request timing histograms (#12644)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

vllm/v1/request.py

@@ -5,8 +5,8 @@ from typing import TYPE_CHECKING, List, Optional, Union
 
 from vllm.lora.request import LoRARequest
 from vllm.sampling_params import SamplingParams
-from vllm.sequence import RequestMetrics
-from vllm.v1.engine import EngineCoreRequest, FinishReason
+from vllm.v1.engine import (EngineCoreEvent, EngineCoreEventType,
+                            EngineCoreRequest, FinishReason)
 from vllm.v1.utils import ConstantList
 
 if TYPE_CHECKING:
@@ -33,14 +33,10 @@ class Request:
         self.sampling_params = sampling_params
         # Because of LoRA, the eos token id can be different for each request.
         self.eos_token_id = eos_token_id
-        self.metrics = RequestMetrics(arrival_time=arrival_time,
-                                      last_token_time=arrival_time,
-                                      first_scheduled_time=None,
-                                      first_token_time=None,
-                                      time_in_queue=None)
         self.lora_request = lora_request
 
         self.status = RequestStatus.WAITING
+        self.events: List[EngineCoreEvent] = []
         self.stop_reason: Union[int, str, None] = None
         assert sampling_params.max_tokens is not None
         self.max_tokens = sampling_params.max_tokens
@@ -83,6 +79,21 @@ class Request:
             lora_request=request.lora_request,
         )
 
+    def queued(self, timestamp: Optional[float] = None) -> None:
+        self.events.append(
+            EngineCoreEvent.new_event(EngineCoreEventType.QUEUED, timestamp))
+
+    def scheduled(self, timestamp: Optional[float] = None) -> None:
+        self.events.append(
+            EngineCoreEvent.new_event(EngineCoreEventType.SCHEDULED,
+                                      timestamp))
+
+    def take_events(self) -> Optional[List[EngineCoreEvent]]:
+        if not self.events:
+            return None
+        events, self.events = self.events, []
+        return events
+
     def append_output_token_ids(
         self,
         token_ids: Union[int, List[int]],