haloscope/cache_utils.py

113 lines
4.7 KiB
Python

import copy
import importlib.metadata
import json
import os
from dataclasses import dataclass
from typing import Any, Dict, List, Optional, Tuple, Union
import torch
from packaging import version
# from .configuration_utils import PretrainedConfig
# from .utils import (
# is_hqq_available,
# is_optimum_quanto_available,
# is_torchdynamo_compiling,
# logging,
# )
# from .utils.deprecation import deprecate_kwarg
# if is_hqq_available():
# from hqq.core.quantize import Quantizer as HQQQuantizer
# logger = logging.get_logger(__name__)
class Cache(torch.nn.Module):
"""
Base, abstract class for all caches. The actual data structure is specific to each subclass.
"""
def __init__(self):
super().__init__()
def update(
self,
key_states: torch.Tensor,
value_states: torch.Tensor,
layer_idx: int,
cache_kwargs: Optional[Dict[str, Any]] = None,
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Updates the cache with the new `key_states` and `value_states` for the layer `layer_idx`.
Parameters:
key_states (`torch.Tensor`):
The new key states to cache.
value_states (`torch.Tensor`):
The new value states to cache.
layer_idx (`int`):
The index of the layer to cache the states for.
cache_kwargs (`Dict[str, Any]`, `optional`):
Additional arguments for the cache subclass. These are specific to each subclass and allow new types of
cache to be created.
Return:
A tuple containing the updated key and value states.
"""
raise NotImplementedError("Make sure to implement `update` in a subclass.")
def get_seq_length(self, layer_idx: Optional[int] = 0) -> int:
"""Returns the sequence length of the cached states. A layer index can be optionally passed."""
# TODO: deprecate this function in favor of `cache_position`
raise NotImplementedError("Make sure to implement `get_seq_length` in a subclass.")
# Deprecate in favor of max-cache-shape because we want to be specifc by what we mean with "max_length"
# Prev some cache objects didn't have "max_length" (SlidingWindowCache or SinkCache) because the cache object technically handles
# infinite amount of tokens. In the codebase what we really need to check is the max capacity of certain cache instances, so
# we change naming to be more explicit
def get_max_length(self) -> Optional[int]:
# logger.warning_once(
# "`get_max_cache()` is deprecated for all Cache classes. Use `get_max_cache_shape()` instead. "
# "Calling `get_max_cache()` will raise error from v4.48"
# )
return self.get_max_cache_shape()
def get_max_cache_shape(self) -> Optional[int]:
"""Returns the maximum sequence length (i.e. max capacity) of the cache object"""
raise NotImplementedError("Make sure to implement `get_max_cache_shape` in a subclass.")
def get_usable_length(self, new_seq_length: int, layer_idx: Optional[int] = 0) -> int:
"""Given the sequence length of the new inputs, returns the usable length of the cache."""
# Cache without size limit -> all cache is usable
# Cache with size limit -> if the length cache plus the length of the new inputs is larger the maximum cache
# length, we will need to evict part of the cache (and thus not all cache is usable)
max_length = self.get_max_cache_shape()
previous_seq_length = self.get_seq_length(layer_idx)
if max_length is not None and previous_seq_length + new_seq_length > max_length:
return max_length - new_seq_length
return previous_seq_length
def reorder_cache(self, beam_idx: torch.LongTensor):
"""Reorders the cache for beam search, given the selected beam indices."""
for layer_idx in range(len(self.key_cache)):
if self.key_cache[layer_idx] != []:
device = self.key_cache[layer_idx].device
self.key_cache[layer_idx] = self.key_cache[layer_idx].index_select(0, beam_idx.to(device))
if self.value_cache[layer_idx] != []:
device = self.value_cache[layer_idx].device
self.value_cache[layer_idx] = self.value_cache[layer_idx].index_select(0, beam_idx.to(device))
@property
def seen_tokens(self):
# logger.warning_once(
# "The `seen_tokens` attribute is deprecated and will be removed in v4.41. Use the `cache_position` "
# "model input instead."
# )
if hasattr(self, "_seen_tokens"):
return self._seen_tokens
else:
return None