Files
sglang/python/sglang/srt/mem_cache/memory_pool_host.py
pansicheng 70cf4abccc 3fs zerocopy (#9109)
Co-authored-by: Zhiqiang Xie <xiezhq@stanford.edu>
2025-08-22 17:56:38 +08:00

739 lines
26 KiB
Python

import abc
import logging
import threading
from enum import IntEnum
from functools import wraps
import psutil
import torch
from sglang.srt.mem_cache.memory_pool import KVCache, MHATokenToKVPool, MLATokenToKVPool
from sglang.srt.utils import is_npu
_is_npu = is_npu()
if not _is_npu:
from sgl_kernel.kvcacheio import (
transfer_kv_all_layer,
transfer_kv_all_layer_lf_pf,
transfer_kv_all_layer_mla,
transfer_kv_all_layer_mla_lf_pf,
transfer_kv_direct,
transfer_kv_per_layer,
transfer_kv_per_layer_mla,
transfer_kv_per_layer_mla_pf_lf,
transfer_kv_per_layer_pf_lf,
)
logger = logging.getLogger(__name__)
class MemoryStateInt(IntEnum):
IDLE = 0
RESERVED = 1
PROTECTED = 2
SYNCED = 3
BACKUP = 4
def synchronized(debug_only=False):
def _decorator(func):
@wraps(func)
def wrapper(self, *args, **kwargs):
if (not debug_only) or self.debug:
with self.lock:
return func(self, *args, **kwargs)
else:
return True
return wrapper
return _decorator
class HostKVCache(abc.ABC):
def __init__(
self,
device_pool: KVCache,
host_to_device_ratio: float,
host_size: int,
page_size: int,
layout: str,
pin_memory: bool,
device: str,
):
self.device_pool = device_pool
self.page_size = page_size
self.layout = layout
self.pin_memory = pin_memory
self.device = device
self.dtype = device_pool.store_dtype
self.size_per_token = self.get_size_per_token()
if host_size > 0:
self.size = int(host_size * 1e9 // self.size_per_token)
else:
self.size = int(device_pool.size * host_to_device_ratio)
# Align the host memory pool size to the page size
self.size = self.size - (self.size % self.page_size)
self.start_layer = device_pool.start_layer
self.end_layer = device_pool.end_layer
assert (
self.size > device_pool.size
), "The host memory should be larger than the device memory with the current protocol"
# Verify there is enough available host memory.
host_mem = psutil.virtual_memory()
requested_bytes = self.size * self.size_per_token
# preserve at least 10GB for other usage
ten_gb = 10 * (1024**3)
available_bytes = host_mem.available - ten_gb
if requested_bytes > available_bytes:
raise ValueError(
f"Not enough host memory available. Requesting "
f"{requested_bytes / 1e9:.2f} GB but only have "
f"{available_bytes / 1e9:.2f} GB free. Please reduce the "
f"size of the hierarchical cache."
)
else:
logger.info(
f"Allocating {requested_bytes / 1e9:.2f} GB host memory for hierarchical KV cache."
)
self.kv_buffer = self.init_kv_buffer()
# A lock for synchronized operations on memory allocation and state transitions.
self.lock = threading.RLock()
self.debug = logger.isEnabledFor(logging.DEBUG)
self.clear()
@abc.abstractmethod
def get_size_per_token(self):
raise NotImplementedError()
@abc.abstractmethod
def init_kv_buffer(self):
raise NotImplementedError()
@abc.abstractmethod
def load_to_device_per_layer(
self, device_pool, host_indices, device_indices, layer_id, io_backend
) -> None:
"""
Load KV data from the host memory pool to the device memory pool for a specific layer.
"""
raise NotImplementedError()
@abc.abstractmethod
def backup_from_device_all_layer(
self, device_pool, host_indices, device_indices, io_backend
) -> None:
"""
Backup KV data from the device memory pool to the host memory pool for all layers.
"""
raise NotImplementedError()
@abc.abstractmethod
def get_flat_data_page(self, index) -> torch.Tensor:
"""
Get a flat data page from the host memory pool.
"""
raise NotImplementedError()
@abc.abstractmethod
def get_dummy_flat_data_page(self) -> torch.Tensor:
"""
Get a dummy flat data page from the host memory pool.
This is used for prefetching or initializing empty pages.
"""
raise NotImplementedError()
@abc.abstractmethod
def set_from_flat_data_page(self, index: int, data_page: torch.Tensor) -> None:
"""
Set a flat data page to the host memory pool.
"""
raise NotImplementedError()
@synchronized()
def clear(self):
# Initialize memory states and tracking structures.
self.mem_state = torch.zeros(
(self.size,), dtype=torch.uint8, device=self.device
)
self.free_slots = torch.arange(self.size, dtype=torch.int64)
def available_size(self):
return len(self.free_slots)
@synchronized()
def alloc(self, need_size: int) -> torch.Tensor:
assert (
need_size % self.page_size == 0
), "The requested size should be a multiple of the page size."
if need_size > self.available_size():
return None
select_index = self.free_slots[:need_size]
self.free_slots = self.free_slots[need_size:]
if self.debug:
self.mem_state[select_index] = MemoryStateInt.RESERVED
return select_index
@synchronized()
def free(self, indices: torch.Tensor) -> int:
self.free_slots = torch.cat([self.free_slots, indices])
if self.debug:
self.mem_state[indices] = MemoryStateInt.IDLE
return len(indices)
@synchronized(debug_only=True)
def get_state(self, indices: torch.Tensor) -> MemoryStateInt:
assert len(indices) > 0, "The indices should not be empty"
states = self.mem_state[indices]
assert (
states == states[0]
).all(), "The memory slots should have the same state {}".format(states)
return MemoryStateInt(states[0].item())
@synchronized(debug_only=True)
def is_reserved(self, indices: torch.Tensor) -> bool:
return self.get_state(indices) == MemoryStateInt.RESERVED
@synchronized(debug_only=True)
def is_protected(self, indices: torch.Tensor) -> bool:
return self.get_state(indices) == MemoryStateInt.PROTECTED
@synchronized(debug_only=True)
def is_synced(self, indices: torch.Tensor) -> bool:
return self.get_state(indices) == MemoryStateInt.SYNCED
@synchronized(debug_only=True)
def is_backup(self, indices: torch.Tensor) -> bool:
return self.get_state(indices) == MemoryStateInt.BACKUP
@synchronized(debug_only=True)
def update_backup(self, indices: torch.Tensor):
if not self.is_synced(indices):
raise ValueError(
f"The host memory slots should be in SYNCED state before turning into BACKUP. "
f"Current state: {self.get_state(indices)}"
)
self.mem_state[indices] = MemoryStateInt.BACKUP
@synchronized(debug_only=True)
def update_prefetch(self, indices: torch.Tensor):
if not self.is_reserved(indices):
raise ValueError(
f"The host memory slots should be in RESERVED state before turning into BACKUP. "
f"Current state: {self.get_state(indices)}"
)
self.mem_state[indices] = MemoryStateInt.BACKUP
@synchronized(debug_only=True)
def update_synced(self, indices: torch.Tensor):
self.mem_state[indices] = MemoryStateInt.SYNCED
@synchronized(debug_only=True)
def protect_write(self, indices: torch.Tensor):
if not self.is_reserved(indices):
raise ValueError(
f"The host memory slots should be RESERVED before write operations. "
f"Current state: {self.get_state(indices)}"
)
self.mem_state[indices] = MemoryStateInt.PROTECTED
@synchronized(debug_only=True)
def protect_load(self, indices: torch.Tensor):
if not self.is_backup(indices):
raise ValueError(
f"The host memory slots should be in BACKUP state before load operations. "
f"Current state: {self.get_state(indices)}"
)
self.mem_state[indices] = MemoryStateInt.PROTECTED
@synchronized(debug_only=True)
def complete_io(self, indices: torch.Tensor):
if not self.is_protected(indices):
raise ValueError(
f"The host memory slots should be PROTECTED during I/O operations. "
f"Current state: {self.get_state(indices)}"
)
self.mem_state[indices] = MemoryStateInt.SYNCED
class MHATokenToKVPoolHost(HostKVCache):
device_pool: MHATokenToKVPool
def __init__(
self,
device_pool: MHATokenToKVPool,
host_to_device_ratio: float,
host_size: int,
page_size: int,
layout: str,
pin_memory: bool = True,
device: str = "cpu",
):
super().__init__(
device_pool,
host_to_device_ratio,
host_size,
page_size,
layout,
pin_memory,
device,
)
self.k_data_refs = [self.k_buffer[i] for i in range(self.layer_num)]
self.v_data_refs = [self.v_buffer[i] for i in range(self.layer_num)]
self.k_data_ptrs = torch.tensor(
[x.data_ptr() for x in self.k_data_refs],
dtype=torch.uint64,
device=self.device_pool.device,
)
self.v_data_ptrs = torch.tensor(
[x.data_ptr() for x in self.v_data_refs],
dtype=torch.uint64,
device=self.device_pool.device,
)
def get_size_per_token(self):
self.head_num = self.device_pool.head_num
self.head_dim = self.device_pool.head_dim
self.layer_num = self.device_pool.layer_num
return self.head_dim * self.head_num * self.layer_num * self.dtype.itemsize * 2
def get_ksize_per_token(self):
return self.get_size_per_token() // 2
def init_kv_buffer(self):
if self.layout == "layer_first":
dims = (2, self.layer_num, self.size, self.head_num, self.head_dim)
elif self.layout == "page_first":
dims = (2, self.size, self.layer_num, self.head_num, self.head_dim)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
self.token_stride_size = self.head_num * self.head_dim * self.dtype.itemsize
self.layout_dim = self.token_stride_size * self.layer_num
return torch.empty(
dims,
dtype=self.dtype,
device=self.device,
pin_memory=self.pin_memory,
)
@property
def k_buffer(self):
return self.kv_buffer[0]
@property
def v_buffer(self):
return self.kv_buffer[1]
def load_to_device_per_layer(
self,
device_pool,
host_indices,
device_indices,
layer_id,
io_backend,
):
if io_backend == "kernel":
if self.layout == "layer_first":
transfer_kv_per_layer(
src_k=self.k_buffer[layer_id],
dst_k=device_pool.k_buffer[layer_id],
src_v=self.v_buffer[layer_id],
dst_v=device_pool.v_buffer[layer_id],
src_indices=host_indices,
dst_indices=device_indices,
item_size=self.token_stride_size,
)
elif self.layout == "page_first":
transfer_kv_per_layer_pf_lf(
src_k=self.k_buffer,
dst_k=device_pool.k_buffer[layer_id],
src_v=self.v_buffer,
dst_v=device_pool.v_buffer[layer_id],
src_indices=host_indices,
dst_indices=device_indices,
layer_id=layer_id,
item_size=self.token_stride_size,
src_layout_dim=self.layout_dim,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
elif io_backend == "direct":
assert (
self.layout == "layer_first"
), f"Direct IO backend only supports layer_first layout."
transfer_kv_direct(
src_layers=[self.k_buffer[layer_id], self.v_buffer[layer_id]],
dst_layers=[
device_pool.k_buffer[layer_id],
device_pool.v_buffer[layer_id],
],
src_indices=host_indices,
dst_indices=device_indices,
page_size=self.page_size,
)
else:
raise ValueError(f"Unsupported IO backend: {io_backend}")
def backup_from_device_all_layer(
self, device_pool, host_indices, device_indices, io_backend
):
if io_backend == "kernel":
if self.layout == "layer_first":
transfer_kv_all_layer(
src_k_layers=device_pool.k_data_ptrs,
dst_k_layers=self.k_data_ptrs,
src_v_layers=device_pool.v_data_ptrs,
dst_v_layers=self.v_data_ptrs,
src_indices=device_indices,
dst_indices=host_indices,
item_size=self.token_stride_size,
num_layers=self.layer_num,
)
elif self.layout == "page_first":
transfer_kv_all_layer_lf_pf(
src_k_layers=device_pool.k_data_ptrs,
dst_k=self.k_buffer,
src_v_layers=device_pool.v_data_ptrs,
dst_v=self.v_buffer,
src_indices=device_indices,
dst_indices=host_indices,
item_size=self.token_stride_size,
dst_layout_dim=self.layout_dim,
num_layers=self.layer_num,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
elif io_backend == "direct":
assert (
self.layout == "layer_first"
), f"Direct IO backend only supports layer_first layout."
transfer_kv_direct(
src_layers=device_pool.k_buffer + device_pool.v_buffer,
dst_layers=self.k_data_refs + self.v_data_refs,
src_indices=device_indices,
dst_indices=host_indices,
page_size=self.page_size,
)
else:
raise ValueError(f"Unsupported IO backend: {io_backend}")
def get_flat_data_page(self, index) -> torch.Tensor:
if self.layout == "layer_first":
return self.kv_buffer[:, :, index : index + self.page_size, :, :].flatten()
elif self.layout == "page_first":
return self.kv_buffer[:, index : index + self.page_size, :, :, :].flatten()
else:
raise ValueError(f"Unsupported layout: {self.layout}")
def get_dummy_flat_data_page(self) -> torch.Tensor:
return torch.zeros(
(2, self.layer_num, self.page_size, self.head_num, self.head_dim),
dtype=self.dtype,
device=self.device,
pin_memory=self.pin_memory,
).flatten()
def set_from_flat_data_page(self, index: int, data_page: torch.Tensor) -> None:
if self.layout == "layer_first":
self.kv_buffer[:, :, index : index + self.page_size, :, :] = (
data_page.reshape(
2,
self.layer_num,
self.page_size,
self.head_num,
self.head_dim,
)
)
elif self.layout == "page_first":
self.kv_buffer[:, index : index + self.page_size, :, :, :] = (
data_page.reshape(
2, self.page_size, self.layer_num, self.head_num, self.head_dim
)
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
def get_buffer_meta(self, keys, indices):
ptr_list = []
key_list = []
kv_buffer_data_ptr = self.kv_buffer.data_ptr()
v_offset = (
self.layer_num
* self.size
* self.head_num
* self.head_dim
* self.dtype.itemsize
)
for index in range(0, len(indices), self.page_size):
k_ptr = (
kv_buffer_data_ptr
+ indices[index]
* self.layer_num
* self.head_num
* self.head_dim
* self.dtype.itemsize
)
v_ptr = k_ptr + v_offset
ptr_list.append(k_ptr)
ptr_list.append(v_ptr)
key_ = keys[index // self.page_size]
key_list.append(f"{key_}_k")
key_list.append(f"{key_}_v")
element_size = (
self.layer_num
* self.dtype.itemsize
* self.page_size
* self.head_num
* self.head_dim
)
element_size_list = [element_size] * len(key_list)
return key_list, ptr_list, element_size_list
def get_buffer_with_hash(self, keys, indices):
assert self.layout == "page_first"
assert len(keys) == (len(indices) // self.page_size)
key_list = []
buf_list = []
for key, i in zip(keys, range(0, len(indices), self.page_size)):
key_list.append(f"{key}-k")
buf_list.append(self.k_buffer[i : i + self.page_size])
key_list.append(f"{key}-v")
buf_list.append(self.v_buffer[i : i + self.page_size])
return key_list, buf_list
class MLATokenToKVPoolHost(HostKVCache):
device_pool: MLATokenToKVPool
def __init__(
self,
device_pool: MLATokenToKVPool,
host_to_device_ratio: float,
host_size: int,
page_size: int,
layout: str,
pin_memory: bool = True,
device: str = "cpu",
):
super().__init__(
device_pool,
host_to_device_ratio,
host_size,
page_size,
layout,
pin_memory,
device,
)
self.data_refs = [self.kv_buffer[i] for i in range(self.layer_num)]
self.data_ptrs = torch.tensor(
[x.data_ptr() for x in self.data_refs],
dtype=torch.uint64,
device=self.device_pool.device,
)
def get_size_per_token(self):
self.kv_lora_rank = self.device_pool.kv_lora_rank
self.qk_rope_head_dim = self.device_pool.qk_rope_head_dim
self.layer_num = self.device_pool.layer_num
return (
(self.kv_lora_rank + self.qk_rope_head_dim)
* 1
* self.dtype.itemsize
* self.layer_num
)
def get_ksize_per_token(self):
return self.get_size_per_token()
def init_kv_buffer(self):
if self.layout == "layer_first":
dims = (
self.layer_num,
self.size,
1,
self.kv_lora_rank + self.qk_rope_head_dim,
)
elif self.layout == "page_first":
dims = (
self.size,
self.layer_num,
1,
self.kv_lora_rank + self.qk_rope_head_dim,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
self.token_stride_size = (
self.kv_lora_rank + self.qk_rope_head_dim
) * self.dtype.itemsize
self.layout_dim = self.token_stride_size * self.layer_num
return torch.empty(
dims,
dtype=self.dtype,
device=self.device,
pin_memory=self.pin_memory,
)
def load_to_device_per_layer(
self, device_pool, host_indices, device_indices, layer_id, io_backend
):
if io_backend == "kernel":
if self.layout == "layer_first":
transfer_kv_per_layer_mla(
src=self.kv_buffer[layer_id],
dst=device_pool.kv_buffer[layer_id],
src_indices=host_indices,
dst_indices=device_indices,
item_size=self.token_stride_size,
)
elif self.layout == "page_first":
transfer_kv_per_layer_mla_pf_lf(
src=self.kv_buffer,
dst=device_pool.kv_buffer[layer_id],
src_indices=host_indices,
dst_indices=device_indices,
layer_id=layer_id,
item_size=self.token_stride_size,
src_layout_dim=self.layout_dim,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
elif io_backend == "direct":
assert (
self.layout == "layer_first"
), f"Direct IO backend only supports layer_first layout."
transfer_kv_direct(
src_layers=[self.kv_buffer[layer_id]],
dst_layers=[device_pool.kv_buffer[layer_id]],
src_indices=host_indices,
dst_indices=device_indices,
page_size=self.page_size,
)
def backup_from_device_all_layer(
self, device_pool, host_indices, device_indices, io_backend
):
if io_backend == "kernel":
if self.layout == "layer_first":
transfer_kv_all_layer_mla(
src_layers=device_pool.data_ptrs,
dst_layers=self.data_ptrs,
src_indices=device_indices,
dst_indices=host_indices,
item_size=self.token_stride_size,
num_layers=self.layer_num,
)
elif self.layout == "page_first":
transfer_kv_all_layer_mla_lf_pf(
src_layers=device_pool.data_ptrs,
dst=self.kv_buffer,
src_indices=device_indices,
dst_indices=host_indices,
item_size=self.token_stride_size,
dst_layout_dim=self.layout_dim,
num_layers=self.layer_num,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
elif io_backend == "direct":
assert (
self.layout == "layer_first"
), f"Direct IO backend only supports layer_first layout."
transfer_kv_direct(
src_layers=device_pool.kv_buffer,
dst_layers=self.data_refs,
src_indices=device_indices,
dst_indices=host_indices,
page_size=self.page_size,
)
else:
raise ValueError(f"Unsupported IO backend: {io_backend}")
def get_flat_data_page(self, index) -> torch.Tensor:
if self.layout == "layer_first":
return self.kv_buffer[:, index : index + self.page_size, :, :].flatten()
elif self.layout == "page_first":
return self.kv_buffer[index : index + self.page_size, :, :, :].flatten()
else:
raise ValueError(f"Unsupported layout: {self.layout}")
def get_dummy_flat_data_page(self) -> torch.Tensor:
return torch.zeros(
(
self.layer_num,
self.page_size,
1,
self.kv_lora_rank + self.qk_rope_head_dim,
),
dtype=self.dtype,
device=self.device,
pin_memory=self.pin_memory,
).flatten()
def set_from_flat_data_page(self, index: int, data_page: torch.Tensor) -> None:
if self.layout == "layer_first":
self.kv_buffer[:, index : index + self.page_size, :, :] = data_page.reshape(
self.layer_num,
self.page_size,
1,
self.kv_lora_rank + self.qk_rope_head_dim,
)
elif self.layout == "page_first":
self.kv_buffer[index : index + self.page_size, :, :, :] = data_page.reshape(
self.page_size,
self.layer_num,
1,
self.kv_lora_rank + self.qk_rope_head_dim,
)
else:
raise ValueError(f"Unsupported layout: {self.layout}")
def get_buffer_meta(self, keys, indices):
ptr_list = []
key_list = []
kv_buffer_data_ptr = self.kv_buffer.data_ptr()
for index in range(0, len(indices), self.page_size):
k_ptr = (
kv_buffer_data_ptr
+ indices[index]
* self.layer_num
* (self.kv_lora_rank + self.qk_rope_head_dim)
* self.dtype.itemsize
)
ptr_list.append(k_ptr)
key_ = keys[index // self.page_size]
key_list.append(f"{key_}_k")
element_size = (
self.layer_num
* self.dtype.itemsize
* self.page_size
* (self.kv_lora_rank + self.qk_rope_head_dim)
)
element_size_list = [element_size] * len(key_list)
return key_list, ptr_list, element_size_list
def get_buffer_with_hash(self, keys, indices):
assert self.layout == "page_first"
assert len(keys) == (len(indices) // self.page_size)
buf_list = []
for i in range(0, len(indices), self.page_size):
buf_list.append(self.kv_buffer[i : i + self.page_size])
return keys, buf_list