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sglang/python/sglang/kernels/ops/kvcache/hisparse.py
T

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Python

from __future__ import annotations
import functools
from typing import TYPE_CHECKING, NamedTuple
import torch
from sglang.kernels.jit.utils import (
cache_once,
is_arch_support_pdl,
load_jit,
make_cpp_args,
)
if TYPE_CHECKING:
from tvm_ffi.module import Module
_GATHER_BLOCK_SIZE = 64
class HiSparseSpecState(NamedTuple):
"""Persistent cache state and reusable miss workspace for speculative swap.
``cache_index`` stores the two int64 hash banks as
``[num_requests, 2, hash_size]``. ``cache_policy`` uses a control-plane row
for the packed CLOCK states followed by one reference-epoch row per
request: ``[1 + num_requests, hot_buffer_size]``.
``scratch_locs`` and ``scratch_state`` hold reusable miss locations,
counters, and metadata shared by all layers.
"""
cache_index: torch.Tensor
cache_policy: torch.Tensor
scratch_locs: torch.Tensor
scratch_state: torch.Tensor
@cache_once
def _jit_spec_module(
item_size_bytes: int,
block_size: int,
num_top_k: int,
hot_buffer_size: int,
num_steps: int,
record_miss_plan: bool,
) -> Module:
template_args = make_cpp_args(
block_size,
num_top_k,
hot_buffer_size,
item_size_bytes,
num_steps,
record_miss_plan,
is_arch_support_pdl(),
)
return load_jit(
"hisparse_spec",
*template_args,
cuda_files=["kvcacheio/hisparse_spec.cuh"],
cuda_wrappers=[
(
"load_cache_to_device_buffer_spec",
f"load_cache_to_device_buffer_spec<{template_args}>",
)
],
)
def load_cache_to_device_buffer_spec_mla(
*,
top_k_tokens: torch.Tensor,
device_buffer_tokens: torch.Tensor,
host_cache_locs: torch.Tensor,
device_buffer_locs: torch.Tensor,
host_cache: torch.Tensor,
device_buffer: torch.Tensor,
top_k_device_locs: torch.Tensor,
req_pool_indices: torch.Tensor,
seq_lens: torch.Tensor,
state: HiSparseSpecState,
num_real_reqs: torch.Tensor,
miss_src: torch.Tensor | None = None,
miss_dst: torch.Tensor | None = None,
miss_count: torch.Tensor | None = None,
) -> None:
"""Resolve all speculative steps and swap unique misses in one launch pair.
Optional miss-plan outputs use the same protocol as the single-step HiSparse
kernel, so shared-index layers can replay only the Host-to-GPU copies with
``copy_cache_planned_mla``.
"""
_, num_steps, num_top_k = top_k_tokens.shape
if not 2 <= num_steps <= 4:
raise ValueError(
f"HiSparse speculative swap requires 2-4 steps, got {num_steps}."
)
hot_buffer_size = state.cache_policy.size(1)
page_size = device_buffer_tokens.size(1) - hot_buffer_size
item_size_bytes = host_cache.stride(0) * host_cache.element_size()
record_miss_plan = miss_src is not None
if record_miss_plan:
if miss_dst is None or miss_count is None:
raise ValueError(
"miss_src, miss_dst, and miss_count must be provided together."
)
if miss_src.dtype != torch.int64 or miss_dst.dtype != torch.int32:
raise ValueError("miss_src must be int64 and miss_dst must be int32.")
if miss_count.dtype != torch.int32:
raise ValueError("miss_count must be int32.")
plan_capacity = num_steps * num_top_k
batch_size = top_k_tokens.size(0)
if (
miss_src.ndim != 2
or miss_dst.ndim != 2
or miss_src.size(0) < batch_size
or miss_dst.size(0) < batch_size
or miss_src.size(1) < plan_capacity
or miss_dst.size(1) < plan_capacity
):
raise ValueError(
"speculative miss_src/miss_dst must have shape "
f"[batch, >= steps * top_k] (capacity {plan_capacity})."
)
if miss_count.ndim != 1 or miss_count.numel() < batch_size:
raise ValueError("speculative miss_count must have shape [batch].")
if miss_src.stride(0) != miss_dst.stride(0):
raise ValueError("miss_src/miss_dst row strides must match.")
else:
if miss_dst is not None or miss_count is not None:
raise ValueError(
"miss_src, miss_dst, and miss_count must be provided together."
)
empty = torch.empty(0)
miss_src = miss_dst = miss_count = empty
module = _jit_spec_module(
item_size_bytes,
_GATHER_BLOCK_SIZE,
num_top_k,
hot_buffer_size,
num_steps,
record_miss_plan,
)
module.load_cache_to_device_buffer_spec(
top_k_tokens,
device_buffer_tokens,
host_cache_locs,
device_buffer_locs,
host_cache,
device_buffer,
top_k_device_locs,
req_pool_indices,
seq_lens,
state.cache_index,
state.cache_policy,
state.scratch_locs,
state.scratch_state,
num_real_reqs,
page_size,
miss_src,
miss_dst,
miss_count,
)
@functools.cache
def _jit_sparse_module(
item_size_bytes: int,
block_size: int,
num_top_k: int,
hot_buffer_size: int,
is_mla: bool = False,
is_dsv4_layout: bool = False,
top_k_block_size: int = 1,
top_k_is_blocks: bool = False,
record_miss_plan: bool = False,
skip_io: bool = False,
) -> Module:
# record_miss_plan / skip_io are compile-time kernel flags; the
# (False, False) production instantiation stays byte-identical.
template_args = make_cpp_args(
block_size,
num_top_k,
hot_buffer_size,
is_mla,
is_dsv4_layout,
top_k_block_size,
top_k_is_blocks,
record_miss_plan,
skip_io,
)
cache_args = make_cpp_args(
item_size_bytes,
block_size,
num_top_k,
hot_buffer_size,
is_mla,
is_dsv4_layout,
top_k_block_size,
top_k_is_blocks,
record_miss_plan,
skip_io,
)
return load_jit(
"sparse_cache",
*cache_args,
cuda_files=["kvcacheio/hisparse.cuh"],
cuda_wrappers=[
(
"load_cache_to_device_buffer",
f"load_cache_to_device_buffer<{template_args}>",
)
],
)
@functools.cache
def _jit_copy_planned_module(
block_size: int,
is_mla: bool,
is_dsv4_layout: bool,
skip_io: bool,
) -> Module:
template_args = make_cpp_args(block_size, is_mla, is_dsv4_layout, skip_io)
return load_jit(
"sparse_copy_planned",
block_size,
is_mla,
is_dsv4_layout,
skip_io,
cuda_files=["kvcacheio/hisparse.cuh"],
cuda_wrappers=[
(
"copy_cache_planned",
f"copy_cache_planned<{template_args}>",
)
],
)
@functools.cache
def _jit_dsv4_transfer_module(block_size: int) -> Module:
template_args = make_cpp_args(block_size)
return load_jit(
"sparse_cache_dsv4_transfer",
block_size,
cuda_files=["kvcacheio/hisparse.cuh"],
cuda_wrappers=[
(
"transfer_cache_dsv4_mla",
f"transfer_cache_dsv4_mla<{template_args}>",
)
],
)
def transfer_cache_dsv4_mla(
src_ptrs: torch.Tensor,
dst_ptrs: torch.Tensor,
src_indices: torch.Tensor,
dst_indices: torch.Tensor,
block_size: int = 1024,
) -> None:
"""Transfer DSv4 C4 tokens between page-padded C4 buffers."""
module = _jit_dsv4_transfer_module(block_size)
module.transfer_cache_dsv4_mla(
src_ptrs,
dst_ptrs,
src_indices,
dst_indices,
)
def _load_cache_to_device_buffer_mla(
*,
is_dsv4_layout: bool,
top_k_tokens: torch.Tensor,
device_buffer_tokens: torch.Tensor,
host_cache_locs: torch.Tensor,
device_buffer_locs: torch.Tensor,
host_cache: torch.Tensor,
device_buffer: torch.Tensor,
top_k_device_locs: torch.Tensor,
req_pool_indices: torch.Tensor,
seq_lens: torch.Tensor,
lru_slots: torch.Tensor,
item_size_bytes: int,
num_top_k: int,
hot_buffer_size: int,
page_size: int,
block_size: int,
num_real_reqs: torch.Tensor | None,
miss_src: torch.Tensor | None,
miss_dst: torch.Tensor | None,
miss_count: torch.Tensor | None,
skip_io: bool,
) -> None:
assert hot_buffer_size >= num_top_k, (
f"hot_buffer_size ({hot_buffer_size}) must be >= num_top_k ({num_top_k})"
)
record_miss_plan = miss_src is not None
module = _jit_sparse_module(
item_size_bytes,
block_size,
num_top_k,
hot_buffer_size,
is_mla=True,
is_dsv4_layout=is_dsv4_layout,
record_miss_plan=record_miss_plan,
skip_io=skip_io,
)
empty = torch.empty(0, device=top_k_tokens.device)
if num_real_reqs is None:
num_real_reqs = torch.tensor(
[top_k_tokens.size(0)], dtype=torch.int32, device=top_k_tokens.device
)
if record_miss_plan:
assert miss_dst is not None and miss_count is not None
assert miss_src.dtype == torch.int64 and miss_dst.dtype == torch.int32
assert miss_count.dtype == torch.int32
# The kernel indexes both plan rows with one stride.
assert miss_src.stride(0) == miss_dst.stride(0)
else:
# Unused sentinels; the RecordMissPlan=false instantiation never reads them.
miss_src = miss_dst = miss_count = empty
module.load_cache_to_device_buffer(
top_k_tokens,
device_buffer_tokens,
host_cache_locs,
device_buffer_locs,
host_cache,
empty,
device_buffer,
empty,
top_k_device_locs,
req_pool_indices,
seq_lens,
lru_slots,
num_real_reqs,
page_size,
item_size_bytes,
miss_src,
miss_dst,
miss_count,
)
def load_cache_to_device_buffer_mla(
top_k_tokens: torch.Tensor,
device_buffer_tokens: torch.Tensor,
host_cache_locs: torch.Tensor,
device_buffer_locs: torch.Tensor,
host_cache: torch.Tensor,
device_buffer: torch.Tensor,
top_k_device_locs: torch.Tensor,
req_pool_indices: torch.Tensor,
seq_lens: torch.Tensor,
lru_slots: torch.Tensor,
item_size_bytes: int,
num_top_k: int,
hot_buffer_size: int,
page_size: int = 1,
block_size: int = 256,
num_real_reqs: torch.Tensor | None = None,
miss_src: torch.Tensor | None = None,
miss_dst: torch.Tensor | None = None,
miss_count: torch.Tensor | None = None,
skip_io: bool = False,
) -> None:
"""Generic MLA hisparse swap-in: device + host both linear (stride=item_size_bytes).
Optional miss_src/miss_dst/miss_count record the miss plan for replay by
copy_cache_planned_mla; skip_io elides only the KV bytes (timing probe).
"""
_load_cache_to_device_buffer_mla(
is_dsv4_layout=False,
top_k_tokens=top_k_tokens,
device_buffer_tokens=device_buffer_tokens,
host_cache_locs=host_cache_locs,
device_buffer_locs=device_buffer_locs,
host_cache=host_cache,
device_buffer=device_buffer,
top_k_device_locs=top_k_device_locs,
req_pool_indices=req_pool_indices,
seq_lens=seq_lens,
lru_slots=lru_slots,
item_size_bytes=item_size_bytes,
num_top_k=num_top_k,
hot_buffer_size=hot_buffer_size,
page_size=page_size,
block_size=block_size,
num_real_reqs=num_real_reqs,
miss_src=miss_src,
miss_dst=miss_dst,
miss_count=miss_count,
skip_io=skip_io,
)
def load_blocks_to_device_buffer_mha(
top_k_blocks: torch.Tensor,
device_buffer_tokens: torch.Tensor,
host_cache_locs: torch.Tensor,
device_buffer_locs: torch.Tensor,
host_cache_k: torch.Tensor,
host_cache_v: torch.Tensor,
device_buffer_k: torch.Tensor,
device_buffer_v: torch.Tensor,
top_k_device_locs: torch.Tensor,
req_pool_indices: torch.Tensor,
seq_lens: torch.Tensor,
lru_slots: torch.Tensor,
item_size_bytes: int,
hot_buffer_size: int,
sparse_block_size: int,
page_size: int = 1,
block_size: int = 256,
num_real_reqs: torch.Tensor | None = None,
skip_io: bool = False,
) -> None:
"""Swap block-selected MHA K/V into the HiSparse device pool."""
num_top_k_blocks = top_k_blocks.size(1)
num_top_k_tokens = num_top_k_blocks * sparse_block_size
assert hot_buffer_size >= num_top_k_tokens, (
f"hot_buffer_size ({hot_buffer_size}) must be >= selected tokens "
f"({num_top_k_tokens})"
)
assert top_k_device_locs.size(1) >= num_top_k_tokens
k_stride = host_cache_k.stride(0) * host_cache_k.element_size()
v_stride = host_cache_v.stride(0) * host_cache_v.element_size()
assert k_stride == v_stride == item_size_bytes, (
"K/V token strides must equal item_size_bytes: "
f"k_stride={k_stride}, v_stride={v_stride}, "
f"item_size_bytes={item_size_bytes}"
)
module = _jit_sparse_module(
item_size_bytes,
block_size,
num_top_k_blocks,
hot_buffer_size,
is_mla=False,
is_dsv4_layout=False,
top_k_block_size=sparse_block_size,
top_k_is_blocks=True,
record_miss_plan=False,
skip_io=skip_io,
)
empty = torch.empty(0, device=top_k_blocks.device)
if num_real_reqs is None:
num_real_reqs = torch.tensor(
[top_k_blocks.size(0)], dtype=torch.int32, device=top_k_blocks.device
)
module.load_cache_to_device_buffer(
top_k_blocks,
device_buffer_tokens,
host_cache_locs,
device_buffer_locs,
host_cache_k,
host_cache_v,
device_buffer_k,
device_buffer_v,
top_k_device_locs,
req_pool_indices,
seq_lens,
lru_slots,
num_real_reqs,
page_size,
item_size_bytes,
empty,
empty,
empty,
)
def copy_cache_planned_mla(
*,
miss_src: torch.Tensor,
miss_dst: torch.Tensor,
miss_count: torch.Tensor,
num_real_reqs: torch.Tensor,
host_cache: torch.Tensor,
device_buffer: torch.Tensor,
item_size_bytes: int,
num_blocks: int = 4,
block_size: int = 1024,
is_dsv4_layout: bool = False,
skip_io: bool = False,
) -> None:
"""Replay a recorded miss plan (host_cache -> device_buffer) for a skip layer.
IO-only, no planning; the small fixed grid keeps the SM footprint low while
overlapped on a side stream. The anchor's slot table stays valid (lockstep).
"""
assert miss_src.dtype == torch.int64 and miss_dst.dtype == torch.int32
assert miss_count.dtype == torch.int32
module = _jit_copy_planned_module(block_size, True, is_dsv4_layout, skip_io)
empty = torch.empty(0)
module.copy_cache_planned(
miss_src,
miss_dst,
miss_count,
num_real_reqs,
host_cache,
empty,
device_buffer,
empty,
num_blocks,
item_size_bytes,
)
def load_cache_to_device_buffer_dsv4_mla(
top_k_tokens: torch.Tensor,
device_buffer_tokens: torch.Tensor,
host_cache_locs: torch.Tensor,
device_buffer_locs: torch.Tensor,
host_cache: torch.Tensor,
device_buffer: torch.Tensor,
top_k_device_locs: torch.Tensor,
req_pool_indices: torch.Tensor,
seq_lens: torch.Tensor,
lru_slots: torch.Tensor,
item_size_bytes: int,
num_top_k: int,
hot_buffer_size: int,
page_size: int = 1,
block_size: int = 256,
num_real_reqs: torch.Tensor | None = None,
miss_src: torch.Tensor | None = None,
miss_dst: torch.Tensor | None = None,
miss_count: torch.Tensor | None = None,
skip_io: bool = False,
) -> None:
"""DSv4 hisparse swap-in: page-padded device + page-padded host C4 layout."""
_load_cache_to_device_buffer_mla(
is_dsv4_layout=True,
top_k_tokens=top_k_tokens,
device_buffer_tokens=device_buffer_tokens,
host_cache_locs=host_cache_locs,
device_buffer_locs=device_buffer_locs,
host_cache=host_cache,
device_buffer=device_buffer,
top_k_device_locs=top_k_device_locs,
req_pool_indices=req_pool_indices,
seq_lens=seq_lens,
lru_slots=lru_slots,
item_size_bytes=item_size_bytes,
num_top_k=num_top_k,
hot_buffer_size=hot_buffer_size,
page_size=page_size,
block_size=block_size,
num_real_reqs=num_real_reqs,
miss_src=miss_src,
miss_dst=miss_dst,
miss_count=miss_count,
skip_io=skip_io,
)