Mojo struct
PagedKVCacheFA3Fallback
@register_passable(trivial)
struct PagedKVCacheFA3Fallback[type_: DType, kv_params_: KVCacheStaticParams, page_size: Int]
The PagedKVCache is a wrapper around the KVCache blocks for a given layer. It is used to access the KVCache blocks for PagedAttention.
Aliases
type = type_:kv_params = kv_params_:KeyIdx = 0:ValueIdx = 1: The entire region of memory for KVCache blocks with shape: [2, total_num_blocks, page_size, num_heads, head_size].
Fields
- blocks (
NDBuffer[type_, 5, MutableAnyOrigin]): - cache_lengths (
NDBuffer[int32, 1, MutableAnyOrigin]): The lookup table with shape: [num_layers, batch_size, max_num_blocks_in_batch]. This is to conform to the expected layout in the DaoLabs FA3 kernel. We have a different lookup table for each layer. - lookup_table (
NDBuffer[int32, 3, MutableAnyOrigin]): - max_seq_length (
SIMD[uint32, 1]): - max_cache_length (
SIMD[uint32, 1]): - layer_idx (
Int): - kv_idx (
Int):
Implemented traits
AnyType,
Copyable,
ExplicitlyCopyable,
KVCacheT,
Movable,
UnknownDestructibility
Methods
__init__
__init__(blocks: NDBuffer[type_, 5, origin], cache_lengths: NDBuffer[int32, 1, origin], lookup_table: NDBuffer[int32, 3, origin], max_seq_length: SIMD[uint32, 1], max_cache_length: SIMD[uint32, 1], layer_idx: Int, kv_idx: Int) -> Self
max_tile_size
static max_tile_size() -> Int
Returns the maximum tile size for the KVCache.
cache_lengths_nd
cache_lengths_nd(self) -> NDBuffer[uint32, 1, MutableAnyOrigin]
cache_length
cache_length(self, batch_idx: Int) -> Int
Returns the length of the cache for a given batch index.
load
load[width: Int](self, bs: Int, head_idx: Int, tok_idx: Int, head_dim_idx: Int) -> SIMD[type_, width]
Loads an element from the given index.
store
store(self, bs: Int, head_idx: Int, tok_idx: Int, head_dim_idx: Int, val: SIMD[type_, size])
Stores an element at the given index.
empty_cache
empty_cache(self) -> Bool
Returns true if the cache_lengths for all requests is 0, false otherwise.
max_prompt_length
max_prompt_length(self) -> SIMD[uint32, 1]
Returns the maximum sequence length across all batches of the current request.
max_context_length
max_context_length(self) -> SIMD[uint32, 1]
Returns the maximum cache length used across all batches of the current request.
block_paged_ptr
block_paged_ptr[tile_size: Int](self, batch_idx: Int, start_tok_idx: Int, head_idx: Int, head_dim_idx: Int = 0) -> UnsafePointer[SIMD[type_, 1]]
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