ollama/kvcache/cache.go
jmorganca b42970063d kvcache: Add check for values that fall out of sliding window cache
The sliding window cache trims entries that are outside the window for
the latest token. This works when we are extending the cache, such as
when the conversation continues. However, if we have a partial overlap
in conversation (including the BOS tokens), then we resume from a past
point in the conversation and the needed tokens are no longer stored
in memory. This verifies that the new window overlaps with the old one
before reusing the cache.

Co-authored-by: Jesse Gross <jesse@ollama.com>
2025-04-02 11:55:48 -07:00

77 lines
2.7 KiB
Go

package kvcache
import (
"errors"
"github.com/ollama/ollama/ml"
"github.com/ollama/ollama/model/input"
)
var (
ErrKvCacheFull = errors.New("could not find a kv cache slot")
ErrNotSupported = errors.New("model does not support operation")
)
type Cache interface {
// ** used by model implementations **
// SetLayer sets the active layer of the cache
SetLayer(layer int)
// Get returns the history of key and value tensors plus a mask
//
// The shape of the tensors is documented in the specific
// cache implementation used.
Get(ctx ml.Context) (ml.Tensor, ml.Tensor, ml.Tensor)
// Put stores a batch of key and value in the cache
//
// The shape of the tensors is documented in the specific
// cache implementation used.
Put(ctx ml.Context, key, value ml.Tensor)
// SetConfig controls optimizations (mostly backend-specific) that may transform
// the output of the cache to work better with specific kernels. If not called,
// the backend settings will be used. This works well when calling Attention.
//
// The config can be overridden by models, especially if they require vanilla
// output when implementing their own version of attention. To do this, pass
// an empty ml.CacheConfig.
//
// Most models will not need to use this.
SetConfig(ml.CacheConfig)
// ** cache management **
// Init sets up runtime parameters.
// backend: Used to allocate cache data storage and execute management operations (such as defrag)
// dtype: The data type for storing cache entries
// maxSequences: The maximum number of sequences stored in the cache - across all batches
// capacity: The number of cache entries to store, per sequence
// maxBatch: The maximum number of tokens that can occur in a single batch
Init(backend ml.Backend, dtype ml.DType, maxSequences, capacity, maxBatch int)
// Close closes the cache and frees resources associated with it
Close()
// StartForward is called before the start of the model's forward pass.
// For each token in the coming batch, there must be a corresponding
// entry in positions and seqs.
StartForward(ctx ml.Context, batch input.Batch) error
// CopyPrefix copies tokens in the range [0, len) from srcSeq to dstSeq
CopyPrefix(srcSeq, dstSeq int, len int32)
// CanResume returns true if the cache can continue with the next token at
// the given position and sequence. Assumes that the caller has already
// verified the contents of the cache.
CanResume(seq int, pos int32) bool
// Remove deletes tokens in the range [beginIndex, endIndex) from seq. Set
// endIndex to math.MaxInt32 to remove everything starting at beginIndex.
//
// If an error occurs, the entire context for the sequence should be
// removed by calling Remove(seq, 0, math.MaxInt32)
Remove(seq int, beginIndex, endIndex int32) error
}