Files
xc-llm-ascend/vllm_ascend/core/scheduler.py
wangxiyuan 973f993a13 [Misc] fix initialize_kv_cache (#1102)
KV cache manger has been changed by
f8a1a2d108

This PR adapt the change into vllm-ascend to make ci happy

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>
2025-06-06 16:46:23 +08:00

408 lines
18 KiB
Python

#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This file is a part of the vllm-ascend project.
#
from collections import deque
from typing import Iterable, Union
from vllm.config import VllmConfig
from vllm.logger import logger
from vllm.multimodal import MULTIMODAL_REGISTRY, MultiModalRegistry
from vllm.utils import cdiv
from vllm.v1.core.sched.output import NewRequestData, SchedulerOutput
from vllm.v1.core.sched.scheduler import Scheduler
from vllm.v1.engine import EngineCoreOutputs
from vllm.v1.kv_cache_interface import KVCacheConfig
from vllm.v1.outputs import ModelRunnerOutput
from vllm.v1.request import Request, RequestStatus
from vllm.v1.structured_output import StructuredOutputManager
from vllm_ascend.utils import vllm_version_is
class AscendScheduler(Scheduler):
"""This Scheduler extends vllm's original v1 scheduler
with prefill-first scheduling strategy."""
def __init__(
self,
vllm_config: VllmConfig,
kv_cache_config: KVCacheConfig,
structured_output_manager: StructuredOutputManager,
mm_registry: MultiModalRegistry = MULTIMODAL_REGISTRY,
include_finished_set: bool = False,
log_stats: bool = False,
) -> None:
super().__init__(vllm_config, kv_cache_config,
structured_output_manager, mm_registry,
include_finished_set, log_stats)
self.scheduled_req_ids: set[str] = set()
self.running: list[Request] = []
if self.vllm_config.kv_transfer_config is not None and \
self.vllm_config.kv_transfer_config.is_kv_consumer:
raise ValueError(
"AscendScheduler cannot be used for decode nodes. ")
def schedule(self) -> SchedulerOutput:
if self.scheduler_config.chunked_prefill_enabled:
return super().schedule()
scheduled_new_reqs: list[Request] = []
scheduled_resumed_reqs: list[Request] = []
scheduled_running_reqs: list[Request] = []
preempted_reqs: list[Request] = []
req_to_new_block_ids: dict[str, list[int]] = {}
num_scheduled_tokens: dict[str, int] = {}
token_budget = self.max_num_scheduled_tokens
# Spec decode-related.
scheduled_spec_decode_tokens: dict[str, list[int]] = {}
# Record scheduled LoRA requests.
scheduled_loras: set[int] = set()
# Use a temporary deque to collect requests that need to be skipped
# and put back at the head of the waiting queue later
skipped_waiting_requests: deque[Request] = deque()
# Schedule prefill requests first.
while self.waiting and token_budget > 0:
if len(self.running) == self.max_num_running_reqs:
break
request = self.waiting[0]
def skip_cur_request():
self.waiting.popleft()
skipped_waiting_requests.appendleft(request)
# Check that adding the request still respects the max_loras
# constraint.
if (self.lora_config and request.lora_request and
(len(scheduled_loras) == self.lora_config.max_loras
and request.lora_request.lora_int_id not in scheduled_loras)):
# Scheduling would exceed max_loras, skip.
skip_cur_request()
continue
prompt_limit = self._get_prompt_limit(request)
# Get already-cached tokens.
computed_blocks, num_computed_tokens = (
self.kv_cache_manager.get_computed_blocks(request))
num_new_tokens = request.num_tokens - num_computed_tokens
if (0 < self.scheduler_config.long_prefill_token_threshold <
num_new_tokens):
num_new_tokens = (
self.scheduler_config.long_prefill_token_threshold)
max_tokens_in_kvcache = (self.kv_cache_config.num_blocks *
self.block_size)
prompt_limit = min(prompt_limit, max_tokens_in_kvcache)
# Finish request that exceeds prompt_limit or kv cache size.
if num_new_tokens > prompt_limit:
logger.warning(
"Input prompt (%d tokens) is too long"
" and exceeds limit of %d",
num_new_tokens,
prompt_limit,
)
request.status = RequestStatus.FINISHED_IGNORED
self.finished_req_ids.add(request.request_id) # type: ignore
self.waiting.popleft()
continue
if num_new_tokens > token_budget:
# Scheduling would exceed token_budget, skip.
skip_cur_request()
continue
assert num_new_tokens > 0
if vllm_version_is("0.9.0"):
blocks = computed_blocks.blocks
else:
blocks = computed_blocks.blocks[0]
watermark = getattr(self.scheduler_config, "watermark", 0.01)
if not self._check_watermark_for_prefill(request, num_new_tokens,
blocks, watermark):
# Scheduling would exceed watermark, skip.
skip_cur_request()
continue
new_blocks = self.kv_cache_manager.allocate_slots(
request, num_new_tokens, new_computed_blocks=computed_blocks)
if new_blocks is None:
# The request cannot be scheduled.
break
self.waiting.popleft()
self.running.append(request)
self.scheduled_req_ids.add(request.request_id)
# Check request status.
if request.status == RequestStatus.WAITING:
scheduled_new_reqs.append(request)
elif request.status == RequestStatus.PREEMPTED:
scheduled_resumed_reqs.append(request)
else:
raise RuntimeError(f"Invalid request status: {request.status}")
if self.lora_config and request.lora_request:
scheduled_loras.add(request.lora_request.lora_int_id)
req_to_new_block_ids[request.request_id] = (
self.kv_cache_manager.get_block_ids(request.request_id))
# Update request info.
num_scheduled_tokens[request.request_id] = num_new_tokens
token_budget -= num_new_tokens
request.status = RequestStatus.RUNNING
request.num_computed_tokens = num_computed_tokens
# Put back any skipped requests at the head of the waiting queue
if skipped_waiting_requests:
self.waiting.extendleft(skipped_waiting_requests)
# If no prefill requests are scheduled,
# Schedule decode requests next.
if len(self.scheduled_req_ids) == 0:
req_index = 0
while req_index < len(self.running) and token_budget > 0:
request = self.running[req_index]
if request.request_id in self.scheduled_req_ids:
# This request has already been scheduled.
req_index += 1
continue
num_new_tokens = (request.num_tokens_with_spec -
request.num_computed_tokens)
if (0 < self.scheduler_config.long_prefill_token_threshold <
num_new_tokens):
num_new_tokens = (
self.scheduler_config.long_prefill_token_threshold)
num_new_tokens = min(num_new_tokens, token_budget)
assert num_new_tokens == 1
while True:
new_blocks = self.kv_cache_manager.allocate_slots(
request, num_new_tokens)
if new_blocks is None:
# The request cannot be scheduled.
# Preempt the lowest-priority request.
preempted_req = self.running.pop()
self.kv_cache_manager.free(preempted_req)
preempted_req.status = RequestStatus.PREEMPTED
preempted_req.num_computed_tokens = 0
self.waiting.appendleft(preempted_req)
preempted_reqs.append(preempted_req)
if preempted_req == request:
# No more request to preempt.
can_schedule = False
break
else:
# The request can be scheduled.
can_schedule = True
break
if not can_schedule:
break
assert new_blocks is not None
# Schedule the request.
scheduled_running_reqs.append(request)
self.scheduled_req_ids.add(request.request_id)
req_to_new_block_ids[request.request_id] = (
new_blocks.get_block_ids())
num_scheduled_tokens[request.request_id] = num_new_tokens
token_budget -= num_new_tokens
req_index += 1
# Speculative decode related.
if request.spec_token_ids:
num_scheduled_spec_tokens = (num_new_tokens +
request.num_computed_tokens -
request.num_tokens)
if num_scheduled_spec_tokens > 0:
# Trim spec_token_ids list to num_scheduled_spec_tokens.
del request.spec_token_ids[num_scheduled_spec_tokens:]
scheduled_spec_decode_tokens[request.request_id] = (
request.spec_token_ids)
# Check if the scheduling constraints are satisfied.
total_num_scheduled_tokens = sum(num_scheduled_tokens.values())
assert total_num_scheduled_tokens <= self.max_num_scheduled_tokens
assert token_budget >= 0
assert len(self.running) <= self.max_num_running_reqs
assert len(scheduled_new_reqs) + len(scheduled_resumed_reqs) + len(
scheduled_running_reqs) <= len(self.running)
# Get the longest common prefix among all requests in the running queue.
# This can be potentially used for cascade attention.
num_common_prefix_blocks = 0
if self.running:
any_request = self.running[0]
num_common_prefix_blocks = (
self.kv_cache_manager.get_num_common_prefix_blocks(
any_request, len(self.running)))
# Construct the scheduler output.
new_reqs_data = [
NewRequestData.from_request(req,
req_to_new_block_ids[req.request_id])
for req in scheduled_new_reqs
]
resumed_reqs_data = [
self._make_cached_request_data(
req,
num_scheduled_tokens[req.request_id],
len(scheduled_spec_decode_tokens.get(req.request_id, ())),
req_to_new_block_ids[req.request_id],
resumed_from_preemption=True,
) for req in scheduled_resumed_reqs
]
running_reqs_data = [
self._make_cached_request_data(
req,
num_scheduled_tokens[req.request_id],
len(scheduled_spec_decode_tokens.get(req.request_id, ())),
req_to_new_block_ids[req.request_id],
resumed_from_preemption=False,
) for req in scheduled_running_reqs
]
scheduler_output = SchedulerOutput(
scheduled_new_reqs=new_reqs_data,
scheduled_cached_reqs=resumed_reqs_data + running_reqs_data,
num_scheduled_tokens=num_scheduled_tokens,
total_num_scheduled_tokens=total_num_scheduled_tokens,
scheduled_spec_decode_tokens=scheduled_spec_decode_tokens,
scheduled_encoder_inputs={},
num_common_prefix_blocks=num_common_prefix_blocks,
# finished_req_ids is an existing state in the scheduler,
# instead of being newly scheduled in this step.
# It contains the request IDs that are finished in between
# the previous and the current steps.
finished_req_ids=self.finished_req_ids, # type: ignore
free_encoder_input_ids=self.encoder_cache_manager.get_freed_ids(),
structured_output_request_ids={},
grammar_bitmask=None,
)
# NOTE(Kuntai): this function is designed for multiple purposes:
# 1. Plan the KV cache store
# 2. Wrap up all the KV cache load / save ops into an opaque object
# 3. Clear the internal states of the connector
if self.connector is not None:
meta = self.connector.build_connector_meta(scheduler_output)
scheduler_output.kv_connector_metadata = meta
# Advance the number of computed tokens for the request AFTER
# the request is scheduled.
# 1. The scheduler_output of the current step has to include the
# original number of scheduled tokens to determine input IDs.
# 2. Advance the number of computed tokens here allowing us to
# schedule the prefill request again immediately in the next
# scheduling step.
# 3. If some tokens (e.g. spec tokens) are rejected later, the number of
# computed tokens will be adjusted in update_from_output.
for req_id, num_scheduled_token in num_scheduled_tokens.items():
self.requests[req_id].num_computed_tokens += num_scheduled_token
self.finished_req_ids = set() # type: ignore
return scheduler_output
def _check_watermark_for_prefill(self,
request,
num_new_tokens,
computed_blocks,
watermark=0.01):
computed_blocks = computed_blocks or []
watermark_blocks = self.kv_cache_config.num_blocks * watermark
num_computed_tokens = (request.num_computed_tokens +
len(computed_blocks) * self.block_size)
num_required_blocks = cdiv(num_new_tokens + num_computed_tokens,
self.block_size)
if vllm_version_is("0.9.0"):
req_blocks = self.kv_cache_manager.single_type_manager.req_to_blocks[
request.request_id]
else:
req_blocks = self.kv_cache_manager.coordinator.get_blocks(
request.request_id)
num_new_blocks = (num_required_blocks - len(req_blocks) -
len(computed_blocks))
num_evictable_computed_blocks = sum(1 for blk in computed_blocks
if blk.ref_cnt == 0)
# If number of free blocks is less than water mark after allocating, don't allocate.
if (self.kv_cache_manager.block_pool.get_num_free_blocks() -
num_evictable_computed_blocks -
num_new_blocks) < watermark_blocks:
return False
return True
def _get_prompt_limit(self, request: Request) -> int:
if (self.scheduler_config.chunked_prefill_enabled
and not self.scheduler_config.is_multi_step):
prompt_limit = self.scheduler_config.max_model_len
else:
prompt_limit = min(
self.scheduler_config.max_model_len,
self.scheduler_config.max_num_batched_tokens,
)
# Model is fine tuned with long context. Return the fine tuned max_len.
if request.lora_request and request.lora_request.long_lora_max_len:
assert prompt_limit <= request.lora_request.long_lora_max_len
return request.lora_request.long_lora_max_len
else:
return prompt_limit
def finish_requests(
self,
request_ids: Union[str, Iterable[str]],
finished_status: RequestStatus,
) -> None:
"""Handles the finish signal from outside the scheduler.
For example, the API server can abort a request when the client
disconnects.
"""
for req_id in request_ids:
request = self.requests.get(req_id)
if request is None:
# Invalid request ID.
continue
if request.status == RequestStatus.RUNNING:
self.scheduled_req_ids.discard(request.request_id)
super().finish_requests(request_ids, finished_status)
def update_from_output(
self,
scheduler_output: SchedulerOutput,
model_runner_output: ModelRunnerOutput,
) -> EngineCoreOutputs:
num_scheduled_tokens = scheduler_output.num_scheduled_tokens
# NOTE(woosuk): As len(self.running) can be up to 1K or more, the below
# loop can be a performance bottleneck. We should do our best to avoid
# expensive operations inside the loop.
for request in self.running:
req_id = request.request_id
num_tokens_scheduled = num_scheduled_tokens.get(req_id, 0)
if num_tokens_scheduled == 0:
# The request was not scheduled in this step.
continue
self.scheduled_req_ids.remove(req_id)
return super().update_from_output(scheduler_output,
model_runner_output)