[Core] feat: Implement Priority Scheduling in V1 Engine (#19057)

Signed-off-by: amit <amit.man@gmail.com>
Co-authored-by: Roger Wang <Rogerw0108@gmail.com>

vllm/v1/request.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import enum
+import time
 from typing import TYPE_CHECKING, Any, Optional, Union
 
 from vllm.multimodal.inputs import MultiModalKwargs, PlaceholderRange
@@ -30,18 +31,23 @@ class Request:
         pooling_params: Optional[PoolingParams],
         eos_token_id: Optional[int],
         client_index: int = 0,
+        arrival_time: Optional[float] = None,
         lora_request: Optional["LoRARequest"] = None,
         structured_output_request: Optional["StructuredOutputRequest"] = None,
         cache_salt: Optional[str] = None,
+        priority: int = 0,
     ) -> None:
         self.request_id = request_id
         self.client_index = client_index
+        self.priority = priority
         self.sampling_params = sampling_params
         self.pooling_params = pooling_params
         # Because of LoRA, the eos token id can be different for each request.
         self.eos_token_id = eos_token_id
         self.lora_request = lora_request
         self.structured_output_request = structured_output_request
+        self.arrival_time = arrival_time if arrival_time is not None else \
+            time.time()
 
         self.status = RequestStatus.WAITING
         if sampling_params and sampling_params.guided_decoding is not None:
@@ -118,11 +124,13 @@ class Request:
             sampling_params=request.sampling_params,
             pooling_params=request.pooling_params,
             eos_token_id=request.eos_token_id,
+            arrival_time=request.arrival_time,
             lora_request=request.lora_request,
             structured_output_request=StructuredOutputRequest(
                 sampling_params=request.sampling_params) \
                     if request.sampling_params else None,
             cache_salt=request.cache_salt,
+            priority=request.priority,
         )
 
     def append_output_token_ids(