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Python module

manager

Abstract base class for KVCacheManager for KV Cache.

KVCacheManager​

class max.pipelines.kv_cache.manager.KVCacheManager(params: KVCacheParams, max_cache_batch_size: int, max_seq_len: int, num_layers: int, devices: List[Device], session: InferenceSession, is_ragged: bool = False)

claim()​

claim(n: int) → List[int]

Claims n blocks of memory in the cache for incoming requests.

This returns a list of sequence ids, which identify a sequence’s location within the cache. This sequence id can then be passed in the fetch function to return the ContinuousBatchingKVCacheCollection for those sequences.

contains()​

contains(seq_id: int) → bool

estimated_memory_size()​

abstract classmethod estimated_memory_size(params: KVCacheParams, max_cache_batch_size: int, max_seq_len: int, num_layers: int, available_cache_memory: int, devices: List[Device]) → int

Returns the estimated total memory usage of the kv cache.

external_claim()​

external_claim(seq_ids: List[int]) → None

Variant of the above where sequence ids are reserved externally.

fetch()​

abstract fetch(seq_ids_and_lengths: dict[int, int], num_steps: int = 1) → List[tuple[max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor]]

increment_cache_lengths()​

increment_cache_lengths(kv_cache_inputs: List[tuple[max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor]], prev_model_inputs: tuple[max.driver.tensor.Tensor, ...]) → List[tuple[max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor, max.driver.tensor.Tensor]]

Prepare the inputs for a multistep execution, generally by incrementing the cache lengths. This should not require a device synchronization, as this would defeat the purpose of multistep execution.

This should also not update the cache lengths in our manager, this batch is still considered in-progress.

input_symbols()​

abstract input_symbols() → List[tuple[max.graph.type.TensorType, max.graph.type.TensorType, max.graph.type.TensorType, max.graph.type.TensorType]]

max_sequence_length​

property max_sequence_length*: int*

The maximum sequence length in current cache.

release()​

release(seq_id: int) → None

Release seq_id provided, marking this sequence as complete. This returns the seq_id back to the available pool of cache memory, allowing it to be reused when a new sequence is claimed.

slots_remaining​

property slots_remaining*: set[int]*

The outstanding cache slots available.

step()​

step(seq_ids_and_lengths: dict[int, int], num_steps: int = 1) → None

Update the cache_lengths objects to not that a new kv projection step has occurred, and that the underlying memory has been written to. This cache_lengths value is then used downstream in fetch to track what section of memory should be used in the kernels.