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sglang/python/sglang/srt/layers/attention/nsa/nsa_indexer.py
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55 KiB
Python

from __future__ import annotations
import contextlib
from abc import ABC, abstractmethod
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
import torch
from einops import rearrange
from sglang.jit_kernel.fused_store_index_cache import (
can_use_nsa_fused_store,
fused_store_index_k_cache,
)
from sglang.srt.environ import envs
from sglang.srt.layers.dp_attention import attn_tp_all_gather_into_tensor
from sglang.srt.layers.layernorm import LayerNorm
from sglang.srt.layers.quantization.fp8_kernel import is_fp8_fnuz
from sglang.srt.layers.utils import MultiPlatformOp
from sglang.srt.utils import add_prefix, ceil_align, is_cuda, is_hip, is_npu
global _use_multi_stream
_is_cuda = is_cuda()
_is_hip = is_hip()
_is_npu = is_npu()
_is_fp8_fnuz = is_fp8_fnuz()
if _is_cuda:
try:
import deep_gemm
except ImportError as e:
deep_gemm = e
if is_npu():
import torch_npu
from sglang.srt.hardware_backend.npu.utils import get_indexer_weight_stream
from sglang.srt.distributed import (
get_attn_context_model_parallel_rank,
get_attn_context_model_parallel_world_size,
)
from sglang.srt.distributed.parallel_state import get_pp_group
from sglang.srt.layers import deep_gemm_wrapper
from sglang.srt.layers.attention.nsa.utils import (
cp_all_gather_rerange_output,
is_nsa_enable_prefill_cp,
is_nsa_prefill_cp_in_seq_split,
)
from sglang.srt.layers.communicator import ScatterMode
from sglang.srt.layers.linear import ReplicatedLinear
from sglang.srt.layers.quantization.base_config import QuantizationConfig
from sglang.srt.layers.rotary_embedding import get_rope_wrapper
from sglang.srt.model_executor.cuda_graph_runner import get_is_capture_mode
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
from sglang.srt.server_args import get_global_server_args
_use_ag_after_qlora = envs.SGLANG_USE_AG_AFTER_QLORA.get()
if TYPE_CHECKING:
from sglang.srt.mem_cache.memory_pool import NSATokenToKVPool
DUAL_STREAM_TOKEN_THRESHOLD = 1024 if _is_cuda else 0
class BaseIndexerMetadata(ABC):
@abstractmethod
def get_seqlens_int32(self) -> torch.Tensor:
"""
Return: (batch_size,) int32 tensor
"""
@abstractmethod
def get_page_table_64(self) -> torch.Tensor:
"""
Return: (batch_size, num_blocks) int32, page table.
The page size of the table is 64.
"""
@abstractmethod
def get_page_table_1(self) -> torch.Tensor:
"""
Return: (batch_size, num_blocks) int32, page table.
The page size of the table is 1.
"""
@abstractmethod
def get_seqlens_expanded(self) -> torch.Tensor:
"""
Return: (sum_extend_seq_len,) int32 tensor
"""
def get_indexer_kvcache_range(self) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Return: (tokens, ), (tokens, ) int32, k_start and k_end in kv cache(token,xxx) for each token.
"""
def get_indexer_seq_len_cpu(self) -> torch.Tensor:
"""
Return: seq lens for each batch.
"""
def get_nsa_extend_len_cpu(self) -> List[int]:
"""
Return: extend seq lens for each batch.
"""
def get_token_to_batch_idx(self) -> torch.Tensor:
"""
Return: batch idx for each token.
"""
@abstractmethod
def topk_transform(
self,
logits: torch.Tensor,
topk: int,
) -> torch.Tensor:
"""
Perform topk selection on the logits and possibly transform the result.
NOTE that attention backend may override this function to do some
transformation, which means the result of this topk_transform may not
be the topk indices of the input logits.
Return: Anything, since it will be passed to the attention backend
for further processing on sparse attention computation.
Don't assume it is the topk indices of the input logits.
"""
def rotate_activation(x: torch.Tensor) -> torch.Tensor:
assert x.dtype == torch.bfloat16
# from sgl_kernel import hadamard_transform
if _is_hip:
from fast_hadamard_transform import hadamard_transform
else:
from sglang.jit_kernel.hadamard import hadamard_transform
hidden_size = x.size(-1)
assert (
hidden_size & (hidden_size - 1)
) == 0, "Hidden size must be a power of 2 for Hadamard transform."
return hadamard_transform(x, scale=hidden_size**-0.5)
class Indexer(MultiPlatformOp):
def __init__(
self,
hidden_size: int,
index_n_heads: int,
index_head_dim: int,
rope_head_dim: int,
index_topk: int,
q_lora_rank: int,
max_position_embeddings: int,
rope_theta: float,
layer_id: int,
scale_fmt: Optional[str],
block_size: int = 128,
rope_scaling: Optional[Dict[str, Any]] = None,
is_neox_style: bool = True,
prefix: str = "",
quant_config: Optional[QuantizationConfig] = None,
alt_stream: Optional[torch.cuda.Stream] = None,
):
super().__init__()
self.hidden_size = hidden_size
self.n_heads = index_n_heads
self.head_dim = index_head_dim
self.rope_head_dim = rope_head_dim
self.index_topk = index_topk
self.q_lora_rank = q_lora_rank
self.layer_id = layer_id
self.alt_stream = alt_stream
self.nsa_enable_prefill_cp = is_nsa_enable_prefill_cp()
if self.nsa_enable_prefill_cp:
self.cp_size = get_attn_context_model_parallel_world_size()
self.cp_rank = get_attn_context_model_parallel_rank()
else:
self.cp_size = None
self.cp_rank = None
if _is_cuda:
self.sm_count = deep_gemm.get_num_sms()
self.half_device_sm_count = ceil_align(self.sm_count // 2, 8)
pp_size = get_global_server_args().pp_size
self.logits_with_pp_recv = pp_size > 1 and not get_pp_group().is_last_rank
else:
self.logits_with_pp_recv = False
self.wq_b = ReplicatedLinear(
self.q_lora_rank,
self.n_heads * self.head_dim,
bias=False,
quant_config=quant_config,
prefix=add_prefix("wq_b", prefix),
)
self.wk = ReplicatedLinear(
self.hidden_size,
self.head_dim,
bias=False,
quant_config=quant_config,
prefix=add_prefix("wk", prefix),
)
self.weights_proj = ReplicatedLinear(
self.hidden_size,
self.n_heads,
bias=False,
params_dtype=torch.bfloat16 if _is_cuda else torch.float32,
prefix=add_prefix("weights_proj", prefix),
)
self.k_norm = LayerNorm(self.head_dim, dtype=torch.float32)
self.rotary_emb = get_rope_wrapper(
rope_head_dim,
rotary_dim=rope_head_dim,
max_position=max_position_embeddings,
base=rope_theta, # type: ignore
rope_scaling=rope_scaling,
is_neox_style=is_neox_style,
device=get_global_server_args().device,
)
self.block_size = block_size
self.scale_fmt = scale_fmt
self.softmax_scale = self.head_dim**-0.5
@contextlib.contextmanager
def _with_real_sm_count(self):
# When pipeline parallelism is enabled, each PP rank initiates a recv operation after the _pp_launch_batch
# request to receive the PP proxy tensor or output from the previous stage, occupying one SM resource.
# Model execution runs in parallel with the recv operation, so the SMs available to the indexer must be reduced
# by 1. Currently, the last rank starts the send result + recv request only after waiting for execution results.
if self.logits_with_pp_recv:
pp_recv_sm_count = 1
with deep_gemm_wrapper.configure_deep_gemm_num_sms(
self.sm_count - pp_recv_sm_count
):
yield
else:
yield
def _weights_proj_bf16_in_fp32_out(self, x: torch.Tensor) -> torch.Tensor:
if deep_gemm_wrapper.ENABLE_JIT_DEEPGEMM:
weight = self.weights_proj.weight
out = torch.empty(
(x.shape[0], weight.shape[0]),
dtype=torch.float32,
device=x.device,
)
deep_gemm_wrapper.gemm_nt_bf16bf16f32(x, weight, out)
return out
if _is_hip:
x = x.to(self.weights_proj.weight.dtype)
weights, _ = self.weights_proj(x)
return weights.float()
@torch.compile(dynamic=True) if not _is_hip else lambda f: f
def _project_and_scale_head_gates(self, x: torch.Tensor):
weights = self._weights_proj_bf16_in_fp32_out(x)
weights = weights * self.n_heads**-0.5
return weights
@torch.compile(dynamic=True) if not _is_hip else lambda f: f
def _get_logits_head_gate(self, x: torch.Tensor, q_scale: torch.Tensor):
weights = self._weights_proj_bf16_in_fp32_out(x)
weights = weights * self.n_heads**-0.5
weights = weights.unsqueeze(-1) * q_scale * self.softmax_scale
return weights
def _get_q_k_bf16(
self,
q_lora: torch.Tensor,
x: torch.Tensor,
positions: torch.Tensor,
enable_dual_stream: bool,
forward_batch: ForwardBatch,
):
if enable_dual_stream:
current_stream = torch.cuda.current_stream()
self.alt_stream.wait_stream(current_stream)
with deep_gemm_wrapper.configure_deep_gemm_num_sms(
self.half_device_sm_count
):
query, _ = self.wq_b(q_lora)
query = rearrange(query, "l (h d) -> l h d", d=self.head_dim)
q_rope, _ = torch.split(
query,
[self.rope_head_dim, self.head_dim - self.rope_head_dim],
dim=-1,
)
with torch.cuda.stream(self.alt_stream):
# TODO we should also put DeepGEMM half SM here?
key, _ = self.wk(x)
key = self.k_norm(key)
k_rope, _ = torch.split(
key,
[self.rope_head_dim, self.head_dim - self.rope_head_dim],
dim=-1,
)
current_stream.wait_stream(self.alt_stream)
else:
query, _ = self.wq_b(q_lora)
query = rearrange(query, "l (h d) -> l h d", d=self.head_dim)
q_rope, _ = torch.split(
query, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1
)
key, _ = self.wk(x)
key = self.k_norm(key)
k_rope, _ = torch.split(
key, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1
)
q_rope, k_rope = self.rotary_emb(positions, q_rope, k_rope)
query[..., : self.rope_head_dim] = q_rope.clone()
key[..., : self.rope_head_dim] = k_rope.clone()
if enable_dual_stream:
current_stream = torch.cuda.current_stream()
self.alt_stream.wait_stream(current_stream)
query = rotate_activation(query)
with torch.cuda.stream(self.alt_stream):
key = rotate_activation(key)
current_stream.wait_stream(self.alt_stream)
else:
query = rotate_activation(query)
key = rotate_activation(key)
# allgather+rerrange
if forward_batch.nsa_cp_metadata is not None and self.nsa_enable_prefill_cp:
key = cp_all_gather_rerange_output(
key.contiguous(),
self.cp_size,
forward_batch,
torch.cuda.current_stream(),
)
return query, key
def _get_k_bf16(
self,
x: torch.Tensor,
positions: torch.Tensor,
enable_dual_stream: bool,
):
# Compute only key, skip query
key, _ = self.wk(x)
key = self.k_norm(key)
k_rope, _ = torch.split(
key, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1
)
_, k_rope = self.rotary_emb(positions, k_rope, k_rope)
key[..., : self.rope_head_dim] = k_rope.clone()
key = rotate_activation(key)
return key
def _get_topk_paged(
self,
forward_batch: ForwardBatch,
layer_id: int,
q_fp8: torch.Tensor,
weights: torch.Tensor,
metadata: BaseIndexerMetadata,
) -> torch.Tensor:
if TYPE_CHECKING:
assert isinstance(forward_batch.token_to_kv_pool, NSATokenToKVPool)
page_size = forward_batch.token_to_kv_pool.page_size
# NOTE(dark): blocksize = 64 is hardcoded in deep_gemm
if _is_hip:
assert page_size == 1, "only support page size 1"
block_tables = metadata.get_page_table_1()
else:
assert page_size == 64, "only support page size 64"
# NOTE(dark): this support extend/decode/decode+graph
block_tables = metadata.get_page_table_64()
max_seq_len = block_tables.shape[1] * page_size
kv_cache_fp8 = forward_batch.token_to_kv_pool.get_index_k_with_scale_buffer(
layer_id=layer_id
)
blocksize = page_size
if (
forward_batch.forward_mode.is_target_verify()
or forward_batch.forward_mode.is_draft_extend(include_v2=True)
):
seqlens_32 = metadata.get_seqlens_expanded()
else:
seqlens_32 = metadata.get_seqlens_int32()
# Reuse pre-computed schedule metadata if available (from init_forward_metadata),
# otherwise fall back to computing it here.
schedule_metadata = getattr(metadata, "paged_mqa_schedule_metadata", None)
if _is_cuda:
if schedule_metadata is None:
schedule_metadata = deep_gemm.get_paged_mqa_logits_metadata(
seqlens_32, blocksize, self.sm_count
)
assert len(q_fp8.shape) == 3
q_fp8 = q_fp8.unsqueeze(1) # the next_n dim is 1 now
assert len(kv_cache_fp8.shape) == 2
block_kv = 1 if _is_hip else 64
num_heads_kv = 1
head_dim_with_sf = 132
if _is_hip:
kv_cache_fp8 = kv_cache_fp8.view(
-1, block_kv, num_heads_kv, head_dim_with_sf
)
else:
kv_cache_fp8 = kv_cache_fp8.view(
kv_cache_fp8.shape[0], block_kv, num_heads_kv, head_dim_with_sf
)
assert len(weights.shape) == 3
weights = weights.squeeze(2)
# When attn_tp_size > 1 or in the MAX_LEN padding mode, padding may exist in the hidden states,
# and it is necessary to extract the actual q length.
q_offset = sum(metadata.get_nsa_extend_len_cpu())
if _is_hip:
from aiter.ops.triton.pa_mqa_logits import deepgemm_fp8_paged_mqa_logits
batch_size, next_n, heads, _ = q_fp8.shape
logits = torch.full(
(batch_size * next_n, max_seq_len),
float("-inf"),
device=q_fp8.device,
dtype=torch.float32,
)
deepgemm_fp8_paged_mqa_logits(
q_fp8,
kv_cache_fp8,
weights,
logits,
seqlens_32,
block_tables,
max_seq_len,
Preshuffle=False,
KVBlockSize=block_kv,
ChunkK=128,
TotalCuCount=256,
WavePerEU=5,
)
else:
logits = deep_gemm.fp8_paged_mqa_logits(
q_fp8[:q_offset],
kv_cache_fp8,
weights[:q_offset],
seqlens_32,
block_tables,
schedule_metadata,
max_seq_len,
clean_logits=False,
)
# NOTE(dark): logits should be cleaned in topk_transform
topk_result = metadata.topk_transform(logits, self.index_topk)
# Restore possible padding exist in the hidden states.
if not _is_hip and q_offset < q_fp8.shape[0]:
pad_len = q_fp8.shape[0] - q_offset
padding = torch.full(
(pad_len, topk_result.shape[1]),
-1,
dtype=topk_result.dtype,
device=topk_result.device,
)
topk_result = torch.cat([topk_result, padding], dim=0)
return topk_result
def _should_chunk_mqa_logits(
self, num_q: int, num_k: int, device: torch.device
) -> Tuple[bool, int]:
"""
Detect whether we need to chunk the MQA logits computation to avoid OOM
Return: (need_chunk, free_mem)
"""
# Quick static check for normal batches
if num_q * num_k < 8_000_000: # 8M elements ≈ 32MB logits
return False, 0
free_mem, total_mem = torch.cuda.mem_get_info(device)
bytes_per_elem = 4 # float32
logits_bytes = num_q * num_k * bytes_per_elem
# Logits should not exceed 50% of free memory or 30% of total memory
need_chunk = (logits_bytes * 2 > free_mem) or (logits_bytes > total_mem * 0.3)
return need_chunk, free_mem
def _get_topk_ragged(
self,
enable_dual_stream: bool,
forward_batch: ForwardBatch,
layer_id: int,
q_fp8: torch.Tensor,
weights: torch.Tensor,
metadata: BaseIndexerMetadata,
) -> torch.Tensor:
if TYPE_CHECKING:
assert isinstance(forward_batch.token_to_kv_pool, NSATokenToKVPool)
assert forward_batch.forward_mode.is_extend_without_speculative()
page_size = forward_batch.token_to_kv_pool.page_size
if _is_hip:
assert page_size == 1, "only support page size 1"
else:
assert page_size == 64, "only support page size 64"
assert len(weights.shape) == 3
assert (
forward_batch.seq_lens_cpu is not None
and forward_batch.extend_seq_lens_cpu is not None
)
weights = weights.squeeze(-1)
if _is_hip:
block_tables = metadata.get_page_table_1()
else:
block_tables = metadata.get_page_table_64()
assert (
forward_batch.seq_lens_cpu is not None
and forward_batch.extend_seq_lens_cpu is not None
)
batch_size = len(block_tables)
token_nums, _, _ = q_fp8.shape
device = q_fp8.device
topk_result = torch.full(
(token_nums, self.index_topk), -1, device=device, dtype=torch.int32
)
if batch_size == 0:
return topk_result
ks, ke = metadata.get_indexer_kvcache_range()
seq_len_sum = forward_batch.seq_lens_sum
max_seq_len = torch.max(forward_batch.seq_lens_cpu).item()
k_fp8, k_scale = forward_batch.token_to_kv_pool.get_index_k_scale_buffer(
layer_id,
forward_batch.seq_lens,
block_tables,
seq_len_sum,
max_seq_len,
)
if _is_fp8_fnuz:
k_fp8 = k_fp8.view(torch.float8_e4m3fnuz)
else:
k_fp8 = k_fp8.view(torch.float8_e4m3fn)
k_scale = k_scale.view(torch.float32).squeeze(-1)
kv_fp8 = (k_fp8, k_scale)
# Check if we need to chunk to avoid OOM
seq_lens_expanded = metadata.get_seqlens_expanded()
token_to_batch_idx = metadata.get_token_to_batch_idx()
q_offset = ks.shape[0]
k_offset = k_fp8.shape[0]
need_chunk, free_mem = self._should_chunk_mqa_logits(q_offset, k_offset, device)
if not need_chunk:
assert q_fp8[:q_offset].shape[0] != 0
with self._with_real_sm_count():
if _is_hip:
from aiter.ops.triton.fp8_mqa_logits import fp8_mqa_logits
kv, scale = kv_fp8
logits = fp8_mqa_logits(
q_fp8[:q_offset], kv, scale, weights[:q_offset], ks, ke
)
else:
logits = deep_gemm.fp8_mqa_logits(
q_fp8[:q_offset],
kv_fp8,
weights[:q_offset],
ks,
ke,
clean_logits=False,
)
assert logits.shape[0] == len(seq_lens_expanded)
assert logits.shape[1] == k_offset
raw_topk_result = metadata.topk_transform(logits, self.index_topk, ks=ks)
topk_result[:q_offset] = raw_topk_result
return topk_result
# Chunk path
bytes_per_elem = 4 # float32
bytes_per_row = k_offset * bytes_per_elem
# Reserve 50% of free memory for logits
max_rows = max(1, int((free_mem * 0.5) // max(bytes_per_row, 1)))
max_rows = min(max_rows, q_offset)
global_topk_offset = metadata.attn_metadata.topk_indices_offset
assert (
seq_lens_expanded.shape[0] == q_offset
), f"seq_lens_expanded length mismatch: {seq_lens_expanded.shape[0]} != {q_offset}"
if global_topk_offset is not None:
assert (
global_topk_offset.shape[0] >= q_offset
), f"topk_indices_offset too short: {global_topk_offset.shape[0]} < {q_offset}"
start = 0
while start < q_offset:
end = min(start + max_rows, q_offset)
with self._with_real_sm_count():
if _is_hip:
from aiter.ops.triton.fp8_mqa_logits import fp8_mqa_logits
kv, scale = kv_fp8
logits_chunk = fp8_mqa_logits(
q_fp8[start:end],
kv,
scale,
weights[start:end],
ks[start:end],
ke[start:end],
)
else:
logits_chunk = deep_gemm.fp8_mqa_logits(
q_fp8[start:end],
kv_fp8,
weights[start:end],
ks[start:end],
ke[start:end],
clean_logits=False,
)
lengths_chunk = seq_lens_expanded[start:end]
# RAGGED: use global offset; PAGED: construct local cu_seqlens_q per chunk
if global_topk_offset is not None:
# RAGGED path
topk_offset_chunk = global_topk_offset[start:end]
cu_seqlens_q_chunk = None
batch_idx_chunk = None
else:
# PAGED path: treat each token as a length-1 sequence
topk_offset_chunk = None
B_chunk = logits_chunk.shape[0]
cu_seqlens_q_chunk = torch.ones(
B_chunk, dtype=torch.int32, device=device
)
batch_idx_chunk = token_to_batch_idx[start:end]
raw_topk_chunk = metadata.topk_transform(
logits_chunk,
self.index_topk,
ks=ks[start:end],
cu_seqlens_q=cu_seqlens_q_chunk,
ke_offset=lengths_chunk,
batch_idx_list=batch_idx_chunk,
topk_indices_offset_override=topk_offset_chunk,
)
topk_result[start:end] = raw_topk_chunk
start = end
return topk_result
def _forward_cuda_k_only(
self,
x: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
layer_id: int,
act_quant,
enable_dual_stream: bool,
metadata: BaseIndexerMetadata,
return_indices: bool = True,
) -> Optional[torch.Tensor]:
assert forward_batch.forward_mode.is_extend_without_speculative()
x_meta = x[0] if isinstance(x, tuple) else x
# Fast path: only compute and store k cache, skip all q and weights ops
key = self._get_k_bf16(x, positions, enable_dual_stream)
if not forward_batch.out_cache_loc.is_contiguous():
forward_batch.out_cache_loc = forward_batch.out_cache_loc.contiguous()
self._store_index_k_cache(
forward_batch=forward_batch,
layer_id=layer_id,
key=key,
act_quant=act_quant,
)
# MHA doesn't need topk_indices
if not return_indices:
return None
# MLA: use dummy logits with topk kernel's fast path to generate indices
# When length <= 2048, naive_topk_cuda directly generates [0,1,...,length-1,-1,...]
seq_lens_expanded = metadata.get_seqlens_expanded()
dummy_logits = torch.zeros(
seq_lens_expanded.shape[0],
self.index_topk,
dtype=torch.float32,
device=x_meta.device,
)
return metadata.topk_transform(dummy_logits, self.index_topk)
def _get_topk_ragged_with_cp(
self,
forward_batch: ForwardBatch,
layer_id: int,
q_fp8: torch.Tensor,
weights: torch.Tensor,
metadata: BaseIndexerMetadata,
kv_len: int,
actual_seq_q: int,
cp_index: List[Tuple[int, int, int]] = None,
) -> torch.Tensor:
if TYPE_CHECKING:
assert isinstance(forward_batch.token_to_kv_pool, NSATokenToKVPool)
page_size = forward_batch.token_to_kv_pool.page_size
assert page_size == 64, "only support page size 64"
assert len(weights.shape) == 3
weights = weights.squeeze(-1)
k_fp8_list = []
k_scale_list = []
ks_list = []
ke_offset_list = []
offset = 0
actual_seq_q_list = []
batch_idx_list = []
block_tables = metadata.get_page_table_64()
assert (
forward_batch.seq_lens_cpu is not None
and forward_batch.extend_seq_lens_cpu is not None
)
if cp_index is not None:
# TODO Multi-batch support has accuracy issues
for batch_idx, start_seq_position, end_seq_position in cp_index:
pre_chunk_offset = (
forward_batch.seq_lens_cpu[batch_idx].item()
- forward_batch.extend_seq_lens_cpu[batch_idx]
)
start_seq_position += pre_chunk_offset
end_seq_position += pre_chunk_offset
if offset == 0 and batch_idx != 0:
offset += forward_batch.extend_seq_lens_cpu[batch_idx - 1]
k_fp8 = forward_batch.token_to_kv_pool.get_index_k_continuous(
layer_id,
end_seq_position,
block_tables[batch_idx],
)
k_scale = forward_batch.token_to_kv_pool.get_index_k_scale_continuous(
layer_id,
end_seq_position,
block_tables[batch_idx],
)
extend_seq_len = end_seq_position - start_seq_position
ks = torch.full(
(extend_seq_len,), offset, dtype=torch.int32, device="cuda"
)
k_fp8_list.append(k_fp8)
k_scale_list.append(k_scale)
ks_list.append(ks)
ke_offset = torch.arange(
start_seq_position + 1,
end_seq_position + 1,
dtype=torch.int32,
device="cuda",
)
ke_offset_list.append(ke_offset)
actual_seq_q = torch.tensor(
[extend_seq_len], dtype=torch.int32, device="cuda"
)
actual_seq_q_list.append(actual_seq_q)
batch_idx_list.append(batch_idx)
k_fp8 = torch.cat(k_fp8_list, dim=0).view(torch.float8_e4m3fn)
k_scale = torch.cat(k_scale_list, dim=0).view(torch.float32).squeeze(-1)
kv_fp8 = (k_fp8, k_scale)
ks = torch.cat(ks_list, dim=0)
ke_offset = torch.cat(ke_offset_list, dim=0)
ke = ks + ke_offset
actual_seq_q = torch.cat(actual_seq_q_list, dim=0)
with self._with_real_sm_count():
logits = deep_gemm.fp8_mqa_logits(
q_fp8,
kv_fp8,
weights,
ks,
ke,
clean_logits=False,
)
topk_result = metadata.topk_transform(
logits,
self.index_topk,
ks=ks,
cu_seqlens_q=actual_seq_q,
ke_offset=ke_offset,
batch_idx_list=batch_idx_list,
)
else:
kv_len = (
forward_batch.seq_lens_cpu[0].item()
- forward_batch.extend_seq_lens_cpu[0]
+ kv_len
)
k_fp8 = forward_batch.token_to_kv_pool.get_index_k_continuous(
layer_id,
kv_len,
block_tables[0],
)
k_scale = forward_batch.token_to_kv_pool.get_index_k_scale_continuous(
layer_id,
kv_len,
block_tables[0],
)
k_fp8 = k_fp8.view(torch.float8_e4m3fn)
k_scale = k_scale.view(torch.float32).squeeze(-1)
kv_fp8 = (k_fp8, k_scale)
ks = torch.full((actual_seq_q,), offset, dtype=torch.int32, device="cuda")
ke_offset = torch.arange(
(kv_len - actual_seq_q) + 1,
kv_len + 1,
dtype=torch.int32,
device="cuda",
)
ke = ks + ke_offset
with self._with_real_sm_count():
logits = deep_gemm.fp8_mqa_logits(
q_fp8,
kv_fp8,
weights,
ks,
ke,
clean_logits=False,
)
actual_seq_q = torch.tensor([actual_seq_q], dtype=torch.int32).to(
device="cuda", non_blocking=True
)
topk_result = metadata.topk_transform(
logits,
self.index_topk,
ks=ks,
cu_seqlens_q=actual_seq_q,
ke_offset=ke_offset,
)
return topk_result
def forward_indexer(
self,
q_fp8: torch.Tensor,
weights: torch.Tensor,
forward_batch: ForwardBatch,
topk: int,
layer_id: int,
) -> Optional[torch.Tensor]:
if not _is_npu:
from sglang.srt.layers.attention.nsa.tilelang_kernel import fp8_index
page_size = forward_batch.token_to_kv_pool.page_size
assert page_size == 64, "only support page size 64"
assert len(weights.shape) == 3
weights = weights.squeeze(-1)
# logits = deep_gemm.fp8_mqa_logits(q_fp8, kv_fp8, weights, ks, ke)
k_fp8_list = []
k_scale_list = []
topk_indices_list = []
block_tables = forward_batch.req_to_token_pool.req_to_token[
forward_batch.req_pool_indices, :
]
strided_indices = torch.arange(
0, block_tables.shape[-1], page_size, device="cuda"
)
block_tables = block_tables[:, strided_indices] // page_size
q_len_start = 0
for i in range(forward_batch.batch_size):
seq_len = forward_batch.seq_lens[i].item()
q_len = (
forward_batch.extend_seq_lens_cpu[i]
if forward_batch.forward_mode.is_extend()
else 1
)
q_len_end = q_len_start + q_len
q_fp8_partial = q_fp8[q_len_start:q_len_end]
q_fp8_partial = q_fp8_partial.unsqueeze(0).contiguous()
weights_partial = weights[q_len_start:q_len_end]
weights_partial = weights_partial.squeeze(-1).unsqueeze(0).contiguous()
k_fp8 = forward_batch.token_to_kv_pool.get_index_k_continuous(
layer_id,
seq_len,
block_tables[i],
)
k_scale = forward_batch.token_to_kv_pool.get_index_k_scale_continuous(
layer_id,
seq_len,
block_tables[i],
)
k_fp8 = k_fp8.view(torch.float8_e4m3fn).unsqueeze(0).contiguous()
k_scale = k_scale.view(torch.float32).squeeze(-1).unsqueeze(0).contiguous()
index_score = fp8_index(
q_fp8_partial,
weights_partial,
k_fp8,
k_scale,
)
end_pos = seq_len
topk_indices = index_score.topk(min(topk, end_pos), dim=-1)[1].squeeze(0)
pad_len = ceil_align(topk_indices.shape[-1], 2048) - topk_indices.shape[-1]
topk_indices = torch.nn.functional.pad(
topk_indices, (0, pad_len), "constant", -1
)
topk_indices_list.append(topk_indices)
q_len_start = q_len_end
topk_indices = torch.cat(topk_indices_list, dim=0)
return topk_indices
def _store_index_k_cache(
self,
forward_batch: ForwardBatch,
layer_id: int,
key: torch.Tensor,
*,
act_quant=None, # fallback only
) -> None:
"""
Store NSA indexer K cache for current step.
Preferred: fused_store_index_k_cache(key, cache, out_cache_loc, page_size)
Fallback : act_quant(key) + token_to_kv_pool.set_index_k_scale_buffer(...)
"""
# Fast path: JIT fused store (CUDA, page_size=64, non-fnuz)
if (
_is_cuda
and (not _is_fp8_fnuz)
and can_use_nsa_fused_store(
key.dtype,
forward_batch.out_cache_loc.dtype,
forward_batch.token_to_kv_pool.page_size,
)
):
# NOTE: wrapper already normalizes shape/contiguity and asserts dtypes.
buf = forward_batch.token_to_kv_pool.get_index_k_with_scale_buffer(
layer_id=layer_id
)
fused_store_index_k_cache(
key,
buf,
forward_batch.out_cache_loc,
forward_batch.token_to_kv_pool.page_size,
)
return
# Fallback: original path
assert act_quant is not None
k_fp8, k_scale = act_quant(key, self.block_size, self.scale_fmt)
out_loc = forward_batch.out_cache_loc
if not out_loc.is_contiguous():
out_loc = out_loc.contiguous()
forward_batch.token_to_kv_pool.set_index_k_scale_buffer(
layer_id=layer_id,
loc=out_loc,
index_k=k_fp8,
index_k_scale=k_scale,
)
def forward_cuda(
self,
x: torch.Tensor,
q_lora: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
layer_id: int,
return_indices: bool = True,
) -> Optional[torch.Tensor]:
if _is_hip:
from sglang.srt.layers.attention.nsa.tilelang_kernel import act_quant
elif not _is_npu:
from sglang.srt.layers.attention.nsa.triton_kernel import act_quant
if TYPE_CHECKING:
assert isinstance(forward_batch.token_to_kv_pool, NSATokenToKVPool)
# When upstream uses fused FP8 RMSNorm+quant, activations may be passed as
# a tuple like (x_fp8, x_scale[, y]). Use `x_meta` for shape/device queries.
x_meta = x[0] if isinstance(x, tuple) else x
metadata = forward_batch.attn_backend.get_indexer_metadata(
layer_id, forward_batch
)
enable_dual_stream = (
self.alt_stream is not None
and get_is_capture_mode()
and q_lora.shape[0] > 0
and q_lora.shape[0] <= DUAL_STREAM_TOKEN_THRESHOLD
)
# skip NSA if attention backend choose to skip this batch
if metadata is None:
return None
# Determine if should skip topk based on sequence length
# We can only skip the logits computation if cuda graph is not involved
skip_logits_computation = False
if forward_batch.forward_mode.is_extend_without_speculative():
if forward_batch.seq_lens_cpu is not None:
max_kv_len = forward_batch.seq_lens_cpu.max().item()
skip_logits_computation = max_kv_len <= self.index_topk
# Optimization: fast path when skipping topk computation
if skip_logits_computation and (not self.nsa_enable_prefill_cp):
return self._forward_cuda_k_only(
x,
positions,
forward_batch,
layer_id,
act_quant,
enable_dual_stream,
metadata,
return_indices,
)
if enable_dual_stream and forward_batch.forward_mode.is_decode_or_idle():
current_stream = torch.cuda.current_stream()
self.alt_stream.wait_stream(current_stream)
weights = self._project_and_scale_head_gates(x)
query, key = self._get_q_k_bf16(
q_lora, x, positions, enable_dual_stream, forward_batch=forward_batch
)
q_fp8, q_scale = act_quant(query, self.block_size, self.scale_fmt)
with torch.cuda.stream(self.alt_stream):
self._store_index_k_cache(
forward_batch=forward_batch,
layer_id=layer_id,
key=key,
act_quant=act_quant,
)
current_stream.wait_stream(self.alt_stream)
weights = weights.unsqueeze(-1) * q_scale * self.softmax_scale
else:
query, key = self._get_q_k_bf16(
q_lora, x, positions, enable_dual_stream, forward_batch=forward_batch
)
if enable_dual_stream:
current_stream = torch.cuda.current_stream()
self.alt_stream.wait_stream(current_stream)
q_fp8, q_scale = act_quant(query, self.block_size, self.scale_fmt)
with torch.cuda.stream(self.alt_stream):
self._store_index_k_cache(
forward_batch=forward_batch,
layer_id=layer_id,
key=key,
act_quant=act_quant,
)
current_stream.wait_stream(self.alt_stream)
else:
q_fp8, q_scale = act_quant(query, self.block_size, self.scale_fmt)
self._store_index_k_cache(
forward_batch=forward_batch,
layer_id=layer_id,
key=key,
act_quant=act_quant,
)
# `_get_logits_head_gate` expects a Tensor. For tuple activations, dequantize
# to a float tensor here (callsite), keeping `_get_logits_head_gate` backend-agnostic.
if isinstance(x, tuple):
assert len(x) in (
2,
3,
), "For tuple input, only (x, x_s) or (x, x_s, y) formats are accepted"
x_q, x_s = x[0], x[1]
if (
x_s is not None
and x_q.dim() == 2
and x_s.dim() == 2
and x_q.shape[0] == x_s.shape[0]
):
m, n = x_q.shape
ng = x_s.shape[1]
if ng > 0 and n % ng == 0:
group = n // ng
x_for_gate = (
x_q.to(torch.float32)
.view(m, ng, group)
.mul_(x_s.to(torch.float32).unsqueeze(-1))
.view(m, n)
.to(torch.bfloat16)
)
else:
x_for_gate = x_q.to(torch.bfloat16)
else:
x_for_gate = x_q.to(torch.bfloat16)
else:
x_for_gate = x
weights = self._get_logits_head_gate(x_for_gate, q_scale)
if _is_cuda or _is_hip:
assert forward_batch.seq_lens_cpu is not None
if len(forward_batch.seq_lens_cpu) == 0:
# this seems b/c max-pad, no worries?
# if x.shape[0] != 0:
# print(
# "HACK: seq_lens empty but x not empty, hackily return all-invalid topk_result"
# )
return torch.full(
(x_meta.shape[0], self.index_topk),
-1,
dtype=torch.int,
device=x_meta.device,
)
if (
forward_batch.forward_mode.is_decode_or_idle()
or forward_batch.forward_mode.is_target_verify()
or forward_batch.forward_mode.is_draft_extend(include_v2=True)
):
topk_result = self._get_topk_paged(
forward_batch, layer_id, q_fp8, weights, metadata
)
else:
if (
forward_batch.nsa_cp_metadata is not None
and is_nsa_prefill_cp_in_seq_split()
):
kv_len_prev = forward_batch.nsa_cp_metadata.kv_len_prev
kv_len_next = forward_batch.nsa_cp_metadata.kv_len_next
actual_seq_q_prev = forward_batch.nsa_cp_metadata.actual_seq_q_prev
actual_seq_q_next = forward_batch.nsa_cp_metadata.actual_seq_q_next
# TODO support mutil-batch
# cp_batch_seq_index_prev = forward_batch.nsa_cp_metadata["cp_batch_seq_index_prev"]
# cp_batch_seq_index_next = forward_batch.nsa_cp_metadata["cp_batch_seq_index_next"]
# TODO prev, next, combined into a single call
q_fp8_prev, q_fp8_next = torch.split(
q_fp8, (q_fp8.shape[0] + 1) // 2, dim=0
)
weights_prev, weights_next = torch.split(
weights, (weights.shape[0] + 1) // 2, dim=0
)
topk_result_prev = self._get_topk_ragged_with_cp(
forward_batch,
layer_id,
q_fp8_prev,
weights_prev,
metadata,
kv_len_prev,
actual_seq_q_prev,
)
topk_result_next = self._get_topk_ragged_with_cp(
forward_batch,
layer_id,
q_fp8_next,
weights_next,
metadata,
kv_len_next,
actual_seq_q_next,
)
return torch.cat([topk_result_prev, topk_result_next], dim=0)
else:
topk_result = self._get_topk_ragged(
enable_dual_stream,
forward_batch,
layer_id,
q_fp8,
weights,
metadata,
)
else:
topk_result = self.forward_indexer(
q_fp8.contiguous(),
weights,
forward_batch,
topk=self.index_topk,
layer_id=layer_id,
)
return topk_result
def forward_npu(
self,
x: torch.Tensor,
q_lora: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
layer_id: int,
layer_scatter_modes=None,
dynamic_scale: torch.Tensor = None,
) -> torch.Tensor:
if forward_batch.attn_backend.forward_metadata.seq_lens_cpu_int is None:
actual_seq_lengths_kv = forward_batch.attn_backend.forward_metadata.seq_lens
else:
actual_seq_lengths_kv = (
forward_batch.attn_backend.forward_metadata.seq_lens_cpu_int
)
is_prefill = (
forward_batch.forward_mode.is_extend()
and not forward_batch.forward_mode.is_draft_extend_v2()
and not forward_batch.forward_mode.is_target_verify()
and not forward_batch.forward_mode.is_draft_extend()
)
cos_sin = self.rotary_emb.cos_sin_cache[positions]
cos, sin = cos_sin.chunk(2, dim=-1)
cos = cos.repeat(1, 2).view(-1, 1, 1, self.rope_head_dim)
sin = sin.repeat(1, 2).view(-1, 1, 1, self.rope_head_dim)
bs = q_lora.shape[0]
if self.alt_stream is not None:
self.alt_stream.wait_stream(torch.npu.current_stream())
with torch.npu.stream(self.alt_stream):
q_lora = (
(q_lora, dynamic_scale) if dynamic_scale is not None else q_lora
)
q = self.wq_b(q_lora)[
0
] # [bs, 1536] @ [1536, 64 * 128] = [bs, 64 * 128]
wq_b_event = self.alt_stream.record_event()
q = q.view(bs, self.n_heads, self.head_dim) # [bs, 64, 128]
q_pe, q_nope = torch.split(
q,
[self.rope_head_dim, self.head_dim - self.rope_head_dim],
dim=-1,
) # [bs, 64, 64 + 64]
q_pe = q_pe.view(bs, self.n_heads, 1, self.rope_head_dim)
q_pe = torch_npu.npu_rotary_mul(q_pe, cos, sin).view(
bs, self.n_heads, self.rope_head_dim
) # [bs, n, d]
q = torch.cat([q_pe, q_nope], dim=-1)
q.record_stream(self.alt_stream)
q_rope_event = self.alt_stream.record_event()
else:
q_lora = (q_lora, dynamic_scale) if dynamic_scale is not None else q_lora
q = self.wq_b(q_lora)[0] # [bs, 1536] @ [1536, 64 * 128] = [bs, 64 * 128]
q = q.view(bs, self.n_heads, self.head_dim) # [bs, 64, 128]
q_pe, q_nope = torch.split(
q,
[self.rope_head_dim, self.head_dim - self.rope_head_dim],
dim=-1,
) # [bs, 64, 64 + 64]
q_pe = q_pe.view(bs, self.n_heads, 1, self.rope_head_dim)
q_pe = torch_npu.npu_rotary_mul(q_pe, cos, sin).view(
bs, self.n_heads, self.rope_head_dim
) # [bs, n, d]
q = torch.cat([q_pe, q_nope], dim=-1)
if envs.SGLANG_NPU_USE_MULTI_STREAM.get():
indexer_weight_stream = get_indexer_weight_stream()
indexer_weight_stream.wait_stream(torch.npu.current_stream())
with torch.npu.stream(indexer_weight_stream):
x = x.view(-1, self.hidden_size)
weights = self.weights_proj(x.float())[0].to(torch.bfloat16)
weights.record_stream(indexer_weight_stream)
weights_event = indexer_weight_stream.record_event()
else:
x = x.view(-1, self.hidden_size)
weights = self.weights_proj(x.float())[0].to(torch.bfloat16)
k_proj = self.wk(x)[0] # [b, s, 7168] @ [7168, 128] = [b, s, 128]
k = self.k_norm(k_proj)
if (
_use_ag_after_qlora
and layer_scatter_modes.layer_input_mode == ScatterMode.SCATTERED
and layer_scatter_modes.attn_mode == ScatterMode.TP_ATTN_FULL
):
k = scattered_to_tp_attn_full(k, forward_batch)
k_pe, k_nope = torch.split(
k,
[self.rope_head_dim, self.head_dim - self.rope_head_dim],
dim=-1,
) # [bs, 64 + 64]
k_pe = k_pe.view(-1, 1, 1, self.rope_head_dim)
k_pe = torch.ops.npu.npu_rotary_mul(k_pe, cos, sin).view(
bs, 1, self.rope_head_dim
) # [bs, 1, d]
k = torch.cat([k_pe, k_nope.unsqueeze(1)], dim=-1) # [bs, 1, 128]
if (
is_prefill
and self.nsa_enable_prefill_cp
and forward_batch.nsa_cp_metadata is not None
):
k = cp_all_gather_rerange_output(
k.contiguous().view(-1, self.head_dim),
self.cp_size,
forward_batch,
torch.npu.current_stream(),
)
forward_batch.token_to_kv_pool.set_index_k_buffer(
layer_id, forward_batch.out_cache_loc, k
)
if is_prefill:
if self.nsa_enable_prefill_cp and forward_batch.nsa_cp_metadata is not None:
forward_batch.attn_backend.forward_metadata.actual_seq_lengths_q = (
forward_batch.nsa_cp_metadata.actual_seq_q_prev_tensor,
forward_batch.nsa_cp_metadata.actual_seq_q_next_tensor,
)
forward_batch.attn_backend.forward_metadata.actual_seq_lengths_kv = (
forward_batch.nsa_cp_metadata.kv_len_prev_tensor,
forward_batch.nsa_cp_metadata.kv_len_next_tensor,
)
actual_seq_lengths_q = (
forward_batch.attn_backend.forward_metadata.actual_seq_lengths_q
)
actual_seq_lengths_kv = (
forward_batch.attn_backend.forward_metadata.actual_seq_lengths_kv
)
else:
actual_seq_lengths_kv = forward_batch.seq_lens
actual_seq_lengths_q = forward_batch.extend_seq_lens.cumsum(dim=0)
else:
if forward_batch.attn_backend.forward_metadata.actual_seq_lengths_q is None:
if (
forward_batch.forward_mode.is_draft_extend_v2()
or forward_batch.forward_mode.is_target_verify()
or forward_batch.forward_mode.is_draft_extend()
):
num_draft_tokens = (
forward_batch.attn_backend.speculative_num_draft_tokens
)
actual_seq_lengths_q = torch.arange(
num_draft_tokens,
num_draft_tokens + bs,
num_draft_tokens,
dtype=torch.int32,
device=k.device,
)
else:
actual_seq_lengths_q = torch.tensor(
[1 + i * 1 for i in range(bs)],
dtype=torch.int32,
device=k.device,
)
else:
actual_seq_lengths_q = (
forward_batch.attn_backend.forward_metadata.actual_seq_lengths_q
)
past_key_states = forward_batch.token_to_kv_pool.get_index_k_buffer(layer_id)
if self.alt_stream is not None:
torch.npu.current_stream().wait_event(q_rope_event)
if envs.SGLANG_NPU_USE_MULTI_STREAM.get():
torch.npu.current_stream().wait_event(weights_event)
if (
_use_ag_after_qlora
and layer_scatter_modes.layer_input_mode == ScatterMode.SCATTERED
and layer_scatter_modes.attn_mode == ScatterMode.TP_ATTN_FULL
):
weights = scattered_to_tp_attn_full(weights, forward_batch)
block_table = forward_batch.attn_backend.forward_metadata.block_tables
if (
is_prefill
and self.nsa_enable_prefill_cp
and forward_batch.nsa_cp_metadata is not None
):
block_table = block_table[: actual_seq_lengths_q[0].numel()]
topk_indices = self.do_npu_cp_balance_indexer(
q.view(-1, self.n_heads, self.head_dim),
past_key_states,
weights,
actual_seq_lengths_q,
actual_seq_lengths_kv,
block_table,
)
return topk_indices
else:
block_table = (
block_table[: actual_seq_lengths_q.size()[0]]
if is_prefill
else block_table
)
topk_indices = torch_npu.npu_lightning_indexer(
query=q.view(-1, self.n_heads, self.head_dim),
key=past_key_states,
weights=weights,
actual_seq_lengths_query=actual_seq_lengths_q.to(torch.int32),
actual_seq_lengths_key=actual_seq_lengths_kv.to(k.device).to(
torch.int32
),
block_table=block_table,
layout_query="TND",
layout_key="PA_BSND",
sparse_count=self.index_topk,
sparse_mode=3,
)
return topk_indices[0]
def do_npu_cp_balance_indexer(
self,
q,
past_key_states,
indexer_weights,
actual_seq_lengths_q,
actual_seq_lengths_kv,
block_table,
):
q_prev, q_next = torch.split(q, (q.size(0) + 1) // 2, dim=0)
weights_prev, weights_next = None, None
if indexer_weights is not None:
weights_prev, weights_next = torch.split(
indexer_weights, (indexer_weights.size(0) + 1) // 2, dim=0
)
weights_prev = weights_prev.contiguous().view(-1, weights_prev.shape[-1])
weights_next = weights_next.contiguous().view(-1, weights_next.shape[-1])
actual_seq_lengths_q_prev, actual_seq_lengths_q_next = actual_seq_lengths_q
actual_seq_lengths_kv_prev, actual_seq_lengths_kv_next = actual_seq_lengths_kv
topk_indices_prev = torch_npu.npu_lightning_indexer(
query=q_prev,
key=past_key_states,
weights=weights_prev,
actual_seq_lengths_query=actual_seq_lengths_q_prev.to(
device=q.device, dtype=torch.int32
),
actual_seq_lengths_key=actual_seq_lengths_kv_prev.to(
device=q.device, dtype=torch.int32
),
block_table=block_table,
layout_query="TND",
layout_key="PA_BSND",
sparse_count=self.index_topk,
sparse_mode=3,
)
topk_indices_next = torch_npu.npu_lightning_indexer(
query=q_next,
key=past_key_states,
weights=weights_next,
actual_seq_lengths_query=actual_seq_lengths_q_next.to(
device=q.device, dtype=torch.int32
),
actual_seq_lengths_key=actual_seq_lengths_kv_next.to(
device=q.device, dtype=torch.int32
),
block_table=block_table,
layout_query="TND",
layout_key="PA_BSND",
sparse_count=self.index_topk,
sparse_mode=3,
)
return topk_indices_prev[0], topk_indices_next[0]
def scattered_to_tp_attn_full(
hidden_states: torch.Tensor,
forward_batch,
) -> torch.Tensor:
hidden_states, local_hidden_states = (
torch.empty(
(forward_batch.input_ids.shape[0], hidden_states.shape[1]),
dtype=hidden_states.dtype,
device=hidden_states.device,
),
hidden_states,
)
attn_tp_all_gather_into_tensor(hidden_states, local_hidden_states.contiguous())
return hidden_states