Files
2025-08-05 19:02:46 +08:00

223 lines
10 KiB
Python

from typing import Dict, List, Optional
import torch
from vllm.attention.backends.abstract import AttentionMetadata
class MambaCacheManager:
def __init__(self, dtype, num_mamba_layers, max_batch_size,
conv_state_shape, temporal_state_shape):
conv_state = torch.empty(size=(num_mamba_layers, max_batch_size) +
conv_state_shape,
dtype=dtype,
device="cuda")
temporal_state = torch.empty(size=(num_mamba_layers, max_batch_size) +
temporal_state_shape,
dtype=dtype,
device="cuda")
self.mamba_cache = (conv_state, temporal_state)
# Maps between the request id and a dict that maps between the seq_id
# and its index inside the self.mamba_cache
self.mamba_cache_indices_mapping: Dict[str, Dict[int, int]] = {}
def current_run_tensors(self, input_ids: torch.Tensor,
attn_metadata: AttentionMetadata, **kwargs):
"""
Return the tensors for the current run's conv and ssm state.
"""
if "seqlen_agnostic_capture_inputs" not in kwargs:
# We get here only on Prefill/Eager mode runs
request_ids_to_seq_ids = kwargs["request_ids_to_seq_ids"]
finished_requests_ids = kwargs["finished_requests_ids"]
self._release_finished_requests(finished_requests_ids)
mamba_cache_tensors = self._prepare_current_run_mamba_cache(
request_ids_to_seq_ids, finished_requests_ids)
else:
# CUDA graph capturing runs
mamba_cache_tensors = kwargs["seqlen_agnostic_capture_inputs"]
return mamba_cache_tensors
def copy_inputs_before_cuda_graphs(self, input_buffers, **kwargs):
"""
Copy the relevant Mamba cache into the CUDA graph input buffer
that was provided during the capture runs
(JambaForCausalLM.mamba_gc_cache_buffer).
"""
assert all(
key in kwargs
for key in ["request_ids_to_seq_ids", "finished_requests_ids"])
finished_requests_ids = kwargs["finished_requests_ids"]
request_ids_to_seq_ids = kwargs["request_ids_to_seq_ids"]
self._release_finished_requests(finished_requests_ids)
self._prepare_current_run_mamba_cache(request_ids_to_seq_ids,
finished_requests_ids)
def get_seqlen_agnostic_capture_inputs(self, batch_size: int):
"""
Provide the CUDA graph capture runs with a buffer in adjusted size.
The buffer is used to maintain the Mamba Cache during the CUDA graph
replay runs.
"""
return tuple(buffer[:, :batch_size] for buffer in self.mamba_cache)
def _swap_mamba_cache(self, from_index: int, to_index: int):
assert len(self.mamba_cache) > 0
for cache_t in self.mamba_cache:
cache_t[:, [to_index,from_index]] = \
cache_t[:, [from_index,to_index]]
def _copy_mamba_cache(self, from_index: int, to_index: int):
assert len(self.mamba_cache) > 0
for cache_t in self.mamba_cache:
cache_t[:, to_index].copy_(cache_t[:, from_index],
non_blocking=True)
def _move_out_if_already_occupied(self, index: int,
all_occupied_indices: List[int]):
if index in all_occupied_indices:
first_free_index = self._first_free_index_in_mamba_cache()
# In case occupied, move the occupied to a new empty block
self._move_cache_index_and_mappings(from_index=index,
to_index=first_free_index)
def _assign_seq_id_to_mamba_cache_in_specific_dest(self, cur_rid: str,
seq_id: int,
destination_index: int):
"""
Assign (req_id,seq_id) pair to a `destination_index` index, if
already occupied, move the occupying index to a free index.
"""
all_occupied_indices = self._get_all_occupied_indices()
if cur_rid not in self.mamba_cache_indices_mapping:
self._move_out_if_already_occupied(
index=destination_index,
all_occupied_indices=all_occupied_indices)
self.mamba_cache_indices_mapping[cur_rid] = {
seq_id: destination_index
}
elif seq_id not in (seq_ids2indices :=
self.mamba_cache_indices_mapping[cur_rid]):
# parallel sampling , where n > 1, assume prefill have
# already happened now we only need to copy the already
# existing cache into the siblings seq_ids caches
self._move_out_if_already_occupied(
index=destination_index,
all_occupied_indices=all_occupied_indices)
index_exists = list(seq_ids2indices.values())[0]
# case of decoding n>1, copy prefill cache to decoding indices
self._copy_mamba_cache(from_index=index_exists,
to_index=destination_index)
self.mamba_cache_indices_mapping[cur_rid][
seq_id] = destination_index
else:
# already exists
cache_index_already_exists = self.mamba_cache_indices_mapping[
cur_rid][seq_id]
if cache_index_already_exists != destination_index:
# In case the seq id already exists but not in
# the right destination, swap it with what's occupying it
self._swap_pair_indices_and_mappings(
from_index=cache_index_already_exists,
to_index=destination_index)
def _prepare_current_run_mamba_cache(
self, request_ids_to_seq_ids: Dict[str, list[int]],
finished_requests_ids: List[str]):
running_indices = []
request_ids_to_seq_ids_flatten = [
(req_id, seq_id)
for req_id, seq_ids in request_ids_to_seq_ids.items()
for seq_id in seq_ids
]
batch_size = len(request_ids_to_seq_ids_flatten)
for dest_index, (request_id,
seq_id) in enumerate(request_ids_to_seq_ids_flatten):
if request_id in finished_requests_ids:
# Do not allocate cache index for requests that run
# and finish right after
continue
self._assign_seq_id_to_mamba_cache_in_specific_dest(
request_id, seq_id, dest_index)
running_indices.append(dest_index)
self._clean_up_first_bs_blocks(batch_size, running_indices)
conv_state = self.mamba_cache[0][:, :batch_size]
temporal_state = self.mamba_cache[1][:, :batch_size]
return (conv_state, temporal_state)
def _get_all_occupied_indices(self):
return [
cache_idx
for seq_ids2indices in self.mamba_cache_indices_mapping.values()
for cache_idx in seq_ids2indices.values()
]
def _clean_up_first_bs_blocks(self, batch_size: int,
indices_for_current_run: List[int]):
# move out all of the occupied but currently not running blocks
# outside of the first n blocks
destination_indices = range(batch_size)
max_possible_batch_size = self.mamba_cache[0].shape[1]
for destination_index in destination_indices:
if destination_index in self._get_all_occupied_indices() and \
destination_index not in indices_for_current_run:
# move not running indices outside of the batch
all_other_indices = list(
range(batch_size, max_possible_batch_size))
first_avail_index = self._first_free_index_in_mamba_cache(
all_other_indices)
self._swap_indices(from_index=destination_index,
to_index=first_avail_index)
def _move_cache_index_and_mappings(self, from_index: int, to_index: int):
self._copy_mamba_cache(from_index=from_index, to_index=to_index)
self._update_mapping_index(from_index=from_index, to_index=to_index)
def _swap_pair_indices_and_mappings(self, from_index: int, to_index: int):
self._swap_mamba_cache(from_index=from_index, to_index=to_index)
self._swap_mapping_index(from_index=from_index, to_index=to_index)
def _swap_mapping_index(self, from_index: int, to_index: int):
for seq_ids2index in self.mamba_cache_indices_mapping.values():
for seq_id, index in seq_ids2index.items():
if from_index == index:
seq_ids2index.update({seq_id: to_index})
elif to_index == index:
seq_ids2index.update({seq_id: from_index})
def _update_mapping_index(self, from_index: int, to_index: int):
for seq_ids2index in self.mamba_cache_indices_mapping.values():
for seq_id, index in seq_ids2index.items():
if from_index == index:
seq_ids2index.update({seq_id: to_index})
return
def _release_finished_requests(self,
finished_seq_groups_req_ids: List[str]):
for req_id in finished_seq_groups_req_ids:
if req_id in self.mamba_cache_indices_mapping:
self.mamba_cache_indices_mapping.pop(req_id)
def _first_free_index_in_mamba_cache(
self, indices_range: Optional[List[int]] = None) -> int:
assert self.mamba_cache is not None
if indices_range is None:
max_possible_batch_size = self.mamba_cache[0].shape[1]
indices_range = list(range(max_possible_batch_size))
all_occupied_indices = self._get_all_occupied_indices()
for i in indices_range:
if i not in all_occupied_indices:
return i
raise Exception("Couldn't find a free spot in the mamba cache! This"
"should never happen")