Files
sglang/python/sglang/srt/mem_cache/chunk_cache.py

115 lines
3.6 KiB
Python

from __future__ import annotations
"""Cache for chunked prefill, used when RadixCache is disabled."""
import logging
from typing import TYPE_CHECKING, Any, Optional
import torch
from sglang.srt.mem_cache.base_prefix_cache import (
BasePrefixCache,
EvictParams,
EvictResult,
InsertParams,
InsertResult,
MatchPrefixParams,
MatchResult,
)
from sglang.srt.mem_cache.swa_memory_pool import SWATokenToKVPoolAllocator
if TYPE_CHECKING:
from sglang.srt.managers.schedule_batch import Req
from sglang.srt.mem_cache.cache_init_params import CacheInitParams
logger = logging.getLogger(__name__)
class ChunkCache(BasePrefixCache):
def __init__(self, params: CacheInitParams):
self.req_to_token_pool = params.req_to_token_pool
self.token_to_kv_pool_allocator = params.token_to_kv_pool_allocator
self.page_size = params.page_size
if self.token_to_kv_pool_allocator:
self.device = self.token_to_kv_pool_allocator.device
else:
self.device = torch.device("cpu")
self.protected_size_ = 0
def is_chunk_cache(self) -> bool:
return True
# NOTE (csy): this is to determine if a cache has prefix matching feature.
# Chunk cache always return True to indicate no prefix matching.
# TODO (csy): Using a prefix cache trait to replace this
@property
def disable(self):
return True
def reset(self):
pass
def match_prefix(self, params: MatchPrefixParams) -> MatchResult:
return MatchResult(
device_indices=torch.empty((0,), dtype=torch.int64),
last_device_node=None,
last_host_node=None,
)
def insert(self, params: InsertParams) -> InsertResult:
# ChunkCache does not support prefix caching, so insert is a no-op
return InsertResult(prefix_len=0)
def cache_finished_req(self, req: Req, is_insert: bool = True):
kv_committed_len = req.pop_committed_kv_cache()
# For decode server: if req.output_ids is empty, we want to free all req.origin_input_ids
kv_indices = self.req_to_token_pool.req_to_token[
req.req_pool_idx, :kv_committed_len
]
self.token_to_kv_pool_allocator.free(kv_indices)
def cache_unfinished_req(self, req: Req, chunked=False):
kv_indices = self.req_to_token_pool.req_to_token[
req.req_pool_idx, : len(req.fill_ids)
]
# `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
req.prefix_indices = kv_indices.to(dtype=torch.int64, copy=True)
def evict(self, params: EvictParams) -> EvictResult:
return EvictResult()
def inc_lock_ref(self, node: Any):
return 0
def dec_lock_ref(self, node: Any, swa_uuid_for_lock: Optional[str] = None):
return 0
def protected_size(self):
# NOTE: no protected size in chunk cache. Chunk cache's eviction is the same with request's lifecycle.
return 0
def pretty_print(self):
return ""
class SWAChunkCache(ChunkCache):
"""ChunkCache with support for sliding window attention."""
def __init__(self, params: CacheInitParams):
assert isinstance(params.token_to_kv_pool_allocator, SWATokenToKVPoolAllocator)
super().__init__(params)
self.sliding_window_size = params.sliding_window_size
self.chunked_prefill_size = params.chunked_prefill_size
def supports_swa(self) -> bool:
assert (
self.sliding_window_size is not None
), "sliding_window_size must be set for SWAChunkCache"
return True
def evict(self, params: EvictParams) -> EvictResult:
return EvictResult()