Files
sglang/python/sglang/srt/memory_pool.py
2024-07-20 14:16:45 -07:00

126 lines
3.8 KiB
Python

"""Memory pool."""
import logging
import torch
logger = logging.getLogger(__name__)
class ReqToTokenPool:
"""A memory pool that maps a request to its token locations."""
def __init__(self, size: int, max_context_len: int):
self.mem_state = torch.ones((size,), dtype=torch.bool, device="cuda")
self.req_to_token = torch.empty(
(size, max_context_len), dtype=torch.int32, device="cuda"
)
self.can_use_mem_size = size
def alloc(self, need_size: int):
if need_size > self.can_use_mem_size:
return None
select_index = (
torch.nonzero(self.mem_state).squeeze(1)[:need_size].to(torch.int32)
)
self.mem_state[select_index] = False
self.can_use_mem_size -= need_size
return select_index
def free(self, free_index: int):
self.mem_state[free_index] = True
if isinstance(free_index, (int,)):
self.can_use_mem_size += 1
else:
self.can_use_mem_size += free_index.shape[0]
def clear(self):
self.mem_state.fill_(True)
self.can_use_mem_size = len(self.mem_state)
class TokenToKVPool:
"""A memory pool that maps a token to its kv cache locations"""
def __init__(
self,
size: int,
dtype: torch.dtype,
head_num: int,
head_dim: int,
layer_num: int,
):
self.size = size
# We also add one slot. This slot is used for writing dummy output from padded tokens.
self.mem_state = torch.ones((self.size + 1,), dtype=torch.bool, device="cuda")
# [size, head_num, head_dim] for each layer
self.k_buffer = [
torch.empty((size + 1, head_num, head_dim), dtype=dtype, device="cuda")
for _ in range(layer_num)
]
self.v_buffer = [
torch.empty((size + 1, head_num, head_dim), dtype=dtype, device="cuda")
for _ in range(layer_num)
]
# Prefetch buffer
self.prefetch_buffer = torch.empty(0, device="cuda", dtype=torch.int32)
self.prefetch_chunk_size = 512
self.can_use_mem_size = self.size
self.clear()
def get_key_buffer(self, layer_id: int):
return self.k_buffer[layer_id]
def get_value_buffer(self, layer_id: int):
return self.v_buffer[layer_id]
def get_kv_buffer(self, layer_id: int):
return self.k_buffer[layer_id], self.v_buffer[layer_id]
def available_size(self):
return self.can_use_mem_size + len(self.prefetch_buffer)
def alloc(self, need_size: int):
buffer_len = len(self.prefetch_buffer)
if need_size <= buffer_len:
select_index = self.prefetch_buffer[:need_size]
self.prefetch_buffer = self.prefetch_buffer[need_size:]
return select_index
addition_size = need_size - buffer_len
alloc_size = max(addition_size, self.prefetch_chunk_size)
select_index = (
torch.nonzero(self.mem_state).squeeze(1)[:alloc_size].to(torch.int32)
)
if select_index.shape[0] < addition_size:
return None
self.mem_state[select_index] = False
self.can_use_mem_size -= len(select_index)
self.prefetch_buffer = torch.cat((self.prefetch_buffer, select_index))
ret_index = self.prefetch_buffer[:need_size]
self.prefetch_buffer = self.prefetch_buffer[need_size:]
return ret_index
def free(self, free_index: torch.Tensor):
self.mem_state[free_index] = True
self.can_use_mem_size += len(free_index)
def clear(self):
self.prefetch_buffer = torch.empty(0, device="cuda", dtype=torch.int32)
self.mem_state.fill_(True)
self.can_use_mem_size = self.size
# We also add one slot. This slot is used for writing dummy output from padded tokens.
self.mem_state[0] = False