[New model] Qwen3-next support (#2917)

### What this PR does / why we need it?
Add Qwen3-next support.

### Does this PR introduce _any_ user-facing change?
Yes, users can use Qwen3 next.
Related doc: https://github.com/vllm-project/vllm-ascend/pull/2916 the
tutorial will be ready in
[here](https://vllm-ascend.readthedocs.io/en/latest/tutorials/multi_npu_qwen3_next.html)

### How was this patch tested?
Doc CI passed

Related: https://github.com/vllm-project/vllm-ascend/issues/2884

Co-Authored-By: Angazenn <supperccell@163.com>
Co-Authored-By: zzzzwwjj <1183291235@qq.com>
Co-Authored-By: MengqingCao <cmq0113@163.com>
Co-Authored-By: linfeng-yuan <1102311262@qq.com>
Co-Authored-By: hust17yixuan <303660421@qq.com>
Co-Authored-By: SunnyLee219 <3294305115@qq.com>
Co-Authored-By: maoxx241 <maoxx241@umn.edu>


- vLLM version: v0.10.2
- vLLM main:
b834b4cbf1

---------

Signed-off-by: MengqingCao <cmq0113@163.com>
Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>
Signed-off-by: Angazenn <supperccell@163.com>
Signed-off-by: Your Name <you@example.com>
Signed-off-by: zzzzwwjj <1183291235@qq.com>
Signed-off-by: linfeng-yuan <1102311262@qq.com>
Signed-off-by: hust17yixuan <303660421@qq.com>
Co-authored-by: MengqingCao <cmq0113@163.com>
Co-authored-by: Angazenn <supperccell@163.com>
Co-authored-by: Your Name <you@example.com>
Co-authored-by: zzzzwwjj <1183291235@qq.com>
Co-authored-by: linfeng-yuan <1102311262@qq.com>
Co-authored-by: hust17yixuan <303660421@qq.com>
This commit is contained in:
wangxiyuan
2025-09-16 01:17:42 +08:00
committed by GitHub
parent b5ccef6115
commit c556038ef0
26 changed files with 3959 additions and 258 deletions

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# adapted from vllm/model_executor/layers/mamba/ops/casual_conv1d.py
# Adapted from https://github.com/vllm-project/vllm/blob/main/vllm/model_executor/layers/mamba/ops/causal_conv1d.py
# SPDX-License-Identifier: Apache-2.0
# Copyright (c) 2024, Tri Dao.
# Adapted from https://github.com/Dao-AILab/causal-conv1d/blob/main/causal_conv1d/causal_conv1d_interface.py
# and https://github.com/vllm-project/vllm/blob/main/vllm/model_executor/layers/mamba/ops/causal_conv1d.py
# mypy: ignore-errors
from typing import Optional, Union
import torch
import torch.nn.functional as F
import triton
import triton.language as tl
PAD_SLOT_ID = -1
def causal_conv1d_ref(
x: torch.Tensor,
weight: torch.Tensor,
bias: Optional[torch.Tensor] = None,
initial_states: Optional[torch.Tensor] = None,
return_final_states: bool = False,
final_states_out: Optional[torch.Tensor] = None,
activation: Optional[str] = "silu",
):
"""
x: (batch, dim, seqlen)
weight: (dim, width)
bias: (dim,)
initial_states: (batch, dim, width - 1)
final_states_out: (batch, dim, width - 1)
out: (batch, dim, seqlen)
"""
if activation not in [None, "silu", "swish"]:
raise NotImplementedError("activation must be None, silu, or swish")
dtype_in = x.dtype
x = x.to(weight.dtype)
seqlen = x.shape[-1]
dim, width = weight.shape
if initial_states is None:
out = F.conv1d(x,
weight.unsqueeze(1),
bias,
padding=width - 1,
groups=dim)
else:
x = torch.cat([initial_states, x], dim=-1)
out = F.conv1d(x, weight.unsqueeze(1), bias, padding=0, groups=dim)
out = out[..., :seqlen]
if return_final_states:
final_states = F.pad(x, (width - 1 - x.shape[-1], 0)).to(
dtype_in) # (batch, dim, width - 1)
if final_states_out is not None:
final_states_out.copy_(final_states)
else:
final_states_out = final_states
out = (out if activation is None else F.silu(out)).to(dtype=dtype_in)
return (out, None) if not return_final_states else (out, final_states_out)
def causal_conv1d_fn(
x: torch.Tensor,
weight: torch.Tensor,
bias: Optional[torch.Tensor] = None,
query_start_loc: Optional[torch.Tensor] = None,
cache_indices: Optional[torch.Tensor] = None,
has_initial_state: Optional[torch.Tensor] = None,
conv_states: Optional[torch.Tensor] = None,
activation: Optional[str] = "silu",
pad_slot_id: int = PAD_SLOT_ID,
):
"""
x: (batch, dim, seqlen) or (dim,cu_seq_len) for varlen
sequences are concatenated from left to right for varlen
weight: (dim, width)
bias: (dim,)
query_start_loc: (batch + 1) int32
The cumulative sequence lengths of the sequences in
the batch, used to index into sequence. prepended by 0.
for example: query_start_loc = torch.Tensor([0,10,16,17]),
x.shape=(dim,17)
cache_indices: (batch) int32
indicates the corresponding state index,
like so: conv_state = conv_states[cache_indices[batch_id]]
has_initial_state: (batch) bool
indicates whether should the kernel take the current state as initial
state for the calculations
conv_states: (...,dim,width - 1) itype
updated inplace if provided
activation: either None or "silu" or "swish"
pad_slot_id: int
if cache_indices is passed, lets the kernel identify padded
entries that will not be processed,
for example: cache_indices = [pad_slot_id, 1, 20, pad_slot_id]
in this case, the kernel will not process entries at
indices 0 and 3
out: (batch, dim, seqlen)
"""
if activation not in [None, "silu", "swish"]:
raise NotImplementedError("activation must be None, silu, or swish")
if x.stride(-1) != 1:
x = x.contiguous()
bias = bias.contiguous() if bias is not None else None
out_ref = []
out_ref_b = []
seqlens = query_start_loc[1:] - query_start_loc[:-1]
seqlens = seqlens.tolist()
splits = torch.split(x, seqlens, dim=-1)
for i in range(len(seqlens)):
x_s = splits[i]
if cache_indices[i] == PAD_SLOT_ID:
continue
out_ref_b.append(
causal_conv1d_ref(
x_s,
weight,
bias,
activation=activation,
return_final_states=True,
final_states_out=conv_states[cache_indices[i]].unsqueeze(0),
initial_states=conv_states[cache_indices[i]]
if has_initial_state[i] else None))
out_ref.append(torch.cat([t[0] for t in out_ref_b], dim=-1))
out_ref_tensor = torch.cat(out_ref, dim=0)
return out_ref_tensor
def causal_conv1d_update_ref(x,
conv_state,
weight,
bias=None,
activation=None,
cache_seqlens=None,
conv_state_indices=None):
"""
x: (batch, dim) or (batch, dim, seqlen)
conv_state: (batch, dim, state_len), where state_len >= width - 1
weight: (dim, width)
bias: (dim,)
cache_seqlens: (batch,), dtype int32.
If not None, the conv_state is treated as a circular buffer.
The conv_state will be updated by copying x to the
conv_state starting at the index
@cache_seqlens % state_len before performing the convolution.
out: (batch, dim) or (batch, dim, seqlen)
"""
if activation not in [None, "silu", "swish"]:
raise NotImplementedError("activation must be None, silu, or swish")
dtype_in = x.dtype
unsqueeze = x.dim() == 2
if unsqueeze:
x = x.unsqueeze(-1)
batch, dim, seqlen = x.shape
width = weight.shape[1]
state_len = conv_state.shape[-1]
assert weight.shape == (dim, width)
if cache_seqlens is None:
x_new = torch.cat([conv_state[conv_state_indices], x], dim=-1).to(
weight.dtype) # (batch, dim, state_len + seqlen)
conv_state[conv_state_indices] = x_new[:, :, -state_len:]
else:
width_idx = torch.arange(
-(width - 1), 0, dtype=torch.long,
device=x.device).unsqueeze(0) + cache_seqlens.unsqueeze(1)
width_idx = (torch.remainder(width_idx, state_len).unsqueeze(1).expand(
-1, dim, -1))
x_new = torch.cat([conv_state.gather(2, width_idx), x],
dim=-1).to(weight.dtype)
copy_idx = torch.arange(
seqlen, dtype=torch.long,
device=x.device).unsqueeze(0) + cache_seqlens.unsqueeze(1)
copy_idx = torch.remainder(copy_idx,
state_len).unsqueeze(1).expand(-1, dim, -1)
conv_state.scatter_(2, copy_idx, x)
out = F.conv1d(x_new, weight.unsqueeze(1), bias, padding=0,
groups=dim)[:, :, -seqlen:]
if unsqueeze:
out = out.squeeze(-1)
return (out if activation is None else F.silu(out)).to(dtype=dtype_in)
@triton.jit()
def _causal_conv1d_update_kernel(
# Pointers to matrices
x_ptr, # (batch, dim, seqlen)
w_ptr, # (dim, width)
bias_ptr,
conv_state_ptr,
cache_seqlens_ptr, # circular buffer
conv_state_indices_ptr,
num_accepted_tokens_ptr,
intermediate_conv_window_ptr,
o_ptr, # (batch, dim, seqlen)
# Matrix dimensions
batch: int,
dim: tl.constexpr,
seqlen: tl.constexpr,
state_len: tl.constexpr,
num_cache_lines: tl.constexpr, # added to support vLLM larger cache lines
# Strides
stride_x_seq: tl.constexpr,
stride_x_dim: tl.constexpr,
stride_x_token: tl.constexpr,
stride_w_dim: tl.constexpr,
stride_w_width: tl.constexpr,
stride_conv_state_seq: tl.constexpr,
stride_conv_state_dim: tl.constexpr,
stride_conv_state_tok: tl.constexpr,
stride_state_indices: tl.constexpr,
stride_inter_seq: tl.constexpr,
stride_inter_step: tl.constexpr,
stride_inter_dim: tl.constexpr,
stride_inter_win: tl.constexpr,
stride_o_seq: tl.constexpr,
stride_o_dim: tl.constexpr,
stride_o_token: tl.constexpr,
# others
pad_slot_id: tl.constexpr,
# Meta-parameters
HAS_BIAS: tl.constexpr,
KERNEL_WIDTH: tl.constexpr,
SILU_ACTIVATION: tl.constexpr,
IS_CONTINUOUS_BATCHING: tl.constexpr,
IS_SPEC_DECODING: tl.constexpr,
NP2_STATELEN: tl.constexpr,
USE_PAD_SLOT: tl.constexpr,
BLOCK_N: tl.constexpr,
SAVE_INTERMEDIATE: tl.constexpr,
):
# ruff: noqa: E501
idx_seq = tl.program_id(0)
if idx_seq >= batch:
return
# [BLOCK_N,] elements along the feature-dimension (channel)
idx_feats = tl.program_id(1) * BLOCK_N + tl.arange(0, BLOCK_N)
if IS_CONTINUOUS_BATCHING:
# mask = idx_seq < batch
conv_state_batch_coord = tl.load(conv_state_indices_ptr +
idx_seq * stride_state_indices).to(
tl.int64)
else:
conv_state_batch_coord = idx_seq
if USE_PAD_SLOT: # noqa
if conv_state_batch_coord == pad_slot_id:
# not processing as this is not the actual sequence
return
if IS_SPEC_DECODING:
# The rolling of conv state:
#
# Before forward, the conv_state is:
# [history1, history2, ..., historyM].
#
# After forward, the conv_state becomes:
# [history2, ..., historyM, draft1, draft2, ..., draftN].
#
# After acceptance, it becomes:
#
# - accept 1 tokens: [history2, ..., historyM, draft1]
# - accept 2 tokens: [history3, ..., historyM, draft1, draft2]
# - and so on.
conv_state_token_offset = tl.load(num_accepted_tokens_ptr +
idx_seq) - 1
else:
conv_state_token_offset = 0
# STEP 1: READ init_state data
conv_states_base = (conv_state_ptr +
(conv_state_batch_coord * stride_conv_state_seq) +
(idx_feats * stride_conv_state_dim))
mask_w = idx_feats < dim
prior_tokens = conv_states_base + conv_state_token_offset * stride_conv_state_tok
if KERNEL_WIDTH >= 2:
conv_states_ptrs = prior_tokens # [BLOCK_N]
col0 = tl.load(conv_states_ptrs, mask_w, 0.0)
if KERNEL_WIDTH >= 3:
conv_states_ptrs = prior_tokens + 1 * stride_conv_state_tok # [BLOCK_N]
col1 = tl.load(conv_states_ptrs, mask_w, 0.0)
if KERNEL_WIDTH >= 4:
conv_states_ptrs = prior_tokens + 2 * stride_conv_state_tok # [BLOCK_N]
col2 = tl.load(conv_states_ptrs, mask_w, 0.0)
if KERNEL_WIDTH == 5:
conv_states_ptrs = prior_tokens + 3 * stride_conv_state_tok # [BLOCK_N]
#col3 = tl.load(conv_states_ptrs, mask_w, 0.0)
# STEP 2: assume state_len > seqlen
idx_tokens = tl.arange(0, NP2_STATELEN) # [BLOCK_M]
# The conv_state updates works in a sliding window manner,
# at each forward pass, the tokens are shift by 1, so we
# load since idx_tokens + 1.
conv_state_ptrs_source = (
conv_state_ptr + (conv_state_batch_coord * stride_conv_state_seq) +
conv_state_token_offset * stride_conv_state_tok +
(idx_feats * stride_conv_state_dim)[None, :] +
((idx_tokens + 1) * stride_conv_state_tok)[:, None]
) # [BLOCK_M, BLOCK_N]
mask = ((conv_state_batch_coord < num_cache_lines)
& ((idx_tokens + seqlen) < state_len)[:, None]
& (idx_feats < dim)[None, :])
conv_state = tl.load(conv_state_ptrs_source, mask, other=0.0)
VAL = state_len - seqlen
x_base = x_ptr + (idx_seq * stride_x_seq) + (idx_feats * stride_x_dim
) # [BLOCK_N]
x_ptrs = (x_base[None, :] + ((idx_tokens - VAL) * stride_x_token)[:, None]
) # [BLOCK_M, BLOCK_N]
mask_x = ((idx_tokens - VAL >= 0)[:, None]
& (idx_tokens - VAL < seqlen)[:, None]
& (idx_feats < dim)[None, :]
) # token-index # token-index # feature-index
loaded_x = tl.load(x_ptrs, mask_x, 0.0)
tl.debug_barrier()
new_conv_state = tl.where(mask, conv_state, loaded_x)
conv_state_base = (conv_state_ptr +
(conv_state_batch_coord * stride_conv_state_seq) +
(idx_feats * stride_conv_state_dim)) # [BLOCK_N,]
conv_state_ptrs_target = (conv_state_base +
(idx_tokens * stride_conv_state_tok)[:, None]
) # [BLOCK_M, BLOCK_N]
mask = (idx_tokens < state_len)[:, None] & (idx_feats < dim)[None, :]
tl.store(conv_state_ptrs_target, new_conv_state, mask)
# STEP 3: init accumulator
if HAS_BIAS:
bias = bias_ptr + idx_feats
mask_bias = idx_feats < dim
acc_preload = tl.load(bias, mask=mask_bias,
other=0.0).to(tl.float32) # [BLOCK_N]
else:
acc_preload = tl.zeros((BLOCK_N, ), dtype=tl.float32)
# STEP 4:
# PRE-LOAD WEIGHTS
# first kernel column, configured for weights to handle BLOCK_N features in range
w_base = w_ptr + (idx_feats * stride_w_dim) # [BLOCK_N,]
mask_w = idx_feats < dim
if KERNEL_WIDTH >= 2:
w_ptrs = w_base + (0 * stride_w_width) # [BLOCK_N] tensor
w_col0 = tl.load(w_ptrs, mask_w, other=0.0)
w_ptrs = w_base + (1 * stride_w_width) # [BLOCK_N] tensor
w_col1 = tl.load(w_ptrs, mask_w, other=0.0)
if KERNEL_WIDTH >= 3:
w_ptrs = w_base + (2 * stride_w_width) # [BLOCK_N] tensor
w_col2 = tl.load(w_ptrs, mask_w, other=0.0)
if KERNEL_WIDTH >= 4:
w_ptrs = w_base + (3 * stride_w_width) # [BLOCK_N] tensor
w_col3 = tl.load(w_ptrs, mask_w, other=0.0)
x_base_1d = x_base # starting of chunk [BLOCK_N]
mask_x_1d = idx_feats < dim
# STEP 5: compute each token
for idx_token in tl.static_range(seqlen):
acc = acc_preload
matrix_w = w_col0
matrix_x = col0
for j in tl.static_range(KERNEL_WIDTH):
if KERNEL_WIDTH == 2:
if j == 1: # KERNEL_WIDTH-1:
matrix_w = w_col1
x_ptrs_1d = x_base_1d + idx_token * stride_x_token # [BLOCK_N]
matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
elif KERNEL_WIDTH == 3:
if j == 1:
matrix_w = w_col1
matrix_x = col1
elif j == 2:
matrix_w = w_col2
x_ptrs_1d = x_base_1d + idx_token * stride_x_token # [BLOCK_N]
matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
elif KERNEL_WIDTH == 4:
if j == 1:
matrix_w = w_col1
matrix_x = col1
elif j == 2:
matrix_w = w_col2
matrix_x = col2
elif j == 3:
matrix_w = w_col3
x_ptrs_1d = x_base_1d + idx_token * stride_x_token # [BLOCK_N]
matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
acc += matrix_x * matrix_w # [BLOCK_N]
if KERNEL_WIDTH == 2:
col0 = matrix_x
elif KERNEL_WIDTH == 3:
col0 = col1
col1 = matrix_x
elif KERNEL_WIDTH == 4:
col0 = col1
col1 = col2
col2 = matrix_x
if SILU_ACTIVATION:
acc = acc / (1 + tl.exp(-acc))
# mask_1d = (idx_token < seqlen) & (
# idx_feats < dim
# ) # token-index # feature-index
maskL = idx_feats < dim
maskR = tl.full(maskL.shape, False, tl.int1)
mask_1d = tl.where(idx_token < seqlen, maskL, maskR)
o_ptrs = (o_ptr + (idx_seq) * stride_o_seq +
idx_token * stride_o_token + (idx_feats * stride_o_dim))
tl.store(o_ptrs, acc, mask=mask_1d)
if SAVE_INTERMEDIATE:
# Save the window state after consuming this token
# Layout: [seq(cache line), step, dim, win(K-1)]
base_ptr = (intermediate_conv_window_ptr +
conv_state_batch_coord * stride_inter_seq +
idx_token * stride_inter_step +
idx_feats * stride_inter_dim)
if KERNEL_WIDTH >= 2:
tl.store(base_ptr + 0 * stride_inter_win, col0, mask=mask_w)
if KERNEL_WIDTH >= 3:
tl.store(base_ptr + 1 * stride_inter_win, col1, mask=mask_w)
if KERNEL_WIDTH >= 4:
tl.store(base_ptr + 2 * stride_inter_win, col2, mask=mask_w)
def causal_conv1d_update_npu(
x: torch.Tensor,
conv_state: torch.Tensor,
weight: torch.Tensor,
bias: Optional[torch.Tensor] = None,
activation: Union[bool, str, None] = None,
cache_seqlens: Optional[torch.Tensor] = None,
conv_state_indices: Optional[torch.Tensor] = None,
num_accepted_tokens: Optional[torch.Tensor] = None,
intermediate_conv_window: Optional[torch.Tensor] = None,
pad_slot_id: int = PAD_SLOT_ID,
metadata=None,
validate_data=False,
):
"""
x: (batch, dim) or (batch, dim, seqlen)
[shape=2: single token prediction]
[shape=3: single or multiple tokens prediction]
conv_state: (..., dim, state_len), where state_len >= width - 1
weight: (dim, width)
bias: (dim,)
cache_seqlens: (batch,), dtype int32.
If not None, the conv_state is treated as a circular buffer.
The conv_state will be updated by copying x to the conv_state
starting at the index
@cache_seqlens % state_len.
conv_state_indices: (batch,), dtype int32
If not None, the conv_state is a larger tensor along the batch dim,
and we are selecting the batch coords specified by conv_state_indices.
Useful for a continuous batching scenario.
pad_slot_id: int
if cache_indices is passed, lets the kernel identify padded
entries that will not be processed,
for example: cache_indices = [pad_slot_id, 1 ,20 ,pad_slot_id]
in this case, the kernel will not process entries at
indices 0 and 3
out: (batch, dim) or (batch, dim, seqlen)
"""
if validate_data:
assert cache_seqlens is None # not implemented yet - ok for vLLM
assert pad_slot_id is not None
assert x.stride(1) == 1
if isinstance(activation, bool):
activation = "silu" if activation is True else None
elif activation is not None:
assert activation in ["silu", "swish"]
unsqueeze = x.dim() == 2
if unsqueeze:
# make it (batch, dim, seqlen) with seqlen == 1
x = x.unsqueeze(-1)
batch, dim, seqlen = x.shape
_, width = weight.shape
# conv_state: (..., dim, state_len), where state_len >= width - 1
num_cache_lines, _, state_len = conv_state.size()
if validate_data:
assert dim == weight.size(0)
assert (
conv_state.stride(-2) == 1
), f"ERROR: expect contiguous along feat-dim of conv_state (currently stride={conv_state.stride()})"
assert state_len >= width - 1
# when above happens, we don't shift-left to keep any records in conv_state
assert dim == conv_state.size(1)
if conv_state_indices is None:
assert conv_state.size(0) >= batch
else:
assert (batch, ) == conv_state_indices.shape
assert num_cache_lines >= batch
assert weight.stride(1) == 1 # Need this
assert cache_seqlens is None # not needed for vLLM - circular buffer
# adopt the strategy in vLLM that overwrite on 'x' directly, rather than creating a new tensor 'o'
out = x
stride_w_dim, stride_w_width = weight.stride()
stride_x_seq, stride_x_dim, stride_x_token = x.stride(
) # X (batch, dim, seqlen)
stride_o_seq, stride_o_dim, stride_o_token = out.stride()
stride_istate_seq, stride_istate_dim, stride_istate_token = conv_state.stride(
)
stride_state_indices = (conv_state_indices.stride(0)
if conv_state_indices is not None else 0)
state_len = width - 1 + (seqlen - 1) # effective state_len needed
np2_statelen = triton.next_power_of_2(state_len)
def grid(META):
return (
batch,
triton.cdiv(dim, META["BLOCK_N"]),
)
# prepare intermediate buffer strides if provided
if intermediate_conv_window is not None:
stride_inter_seq, stride_inter_step, stride_inter_dim, stride_inter_win = (
intermediate_conv_window.stride(0),
intermediate_conv_window.stride(1),
intermediate_conv_window.stride(2),
intermediate_conv_window.stride(3),
)
else:
stride_inter_seq = stride_inter_step = stride_inter_dim = stride_inter_win = 0
_causal_conv1d_update_kernel[grid](
# Pointers to matrices
x,
weight,
bias,
conv_state,
cache_seqlens,
conv_state_indices,
num_accepted_tokens,
intermediate_conv_window
if intermediate_conv_window is not None else x,
out,
# Matrix dimensions
batch,
dim,
seqlen,
state_len,
num_cache_lines,
# stride
stride_x_seq,
stride_x_dim,
stride_x_token,
stride_w_dim,
stride_w_width,
stride_istate_seq,
stride_istate_dim,
stride_istate_token,
stride_state_indices,
stride_inter_seq,
stride_inter_step,
stride_inter_dim,
stride_inter_win,
stride_o_seq,
stride_o_dim,
stride_o_token,
# others
pad_slot_id,
# META
HAS_BIAS=bias is not None,
KERNEL_WIDTH=width,
SILU_ACTIVATION=activation in ["silu", "swish"],
IS_CONTINUOUS_BATCHING=conv_state_indices is not None,
IS_SPEC_DECODING=num_accepted_tokens is not None,
NP2_STATELEN=np2_statelen,
USE_PAD_SLOT=pad_slot_id is not None,
BLOCK_N=128,
SAVE_INTERMEDIATE=intermediate_conv_window is not None,
)
if unsqueeze:
out = out.squeeze(-1)
return out

381
vllm_ascend/ops/fla.py Normal file
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@@ -0,0 +1,381 @@
# Adapt from https://github.com/fla-org/flash-linear-attention/blob/main/fla/modules/layernorm_gated.py
# Copyright (c) 2024, Tri Dao.
# Based on the Triton LayerNorm tutorial: https://triton-lang.org/main/getting-started/tutorials/05-layer-norm.html
# For the backward pass, we keep weight_grad and bias_grad in registers and accumulate.
# This backward pass is faster for dimensions up to 8k, but after that it's much slower due to register spilling.
# The models we train have hidden dim up to 8k anyway (e.g. Llama 70B), so this is fine.
# mypy: ignore-errors
import torch
import torch.nn.functional as F
import triton
import triton.language as tl
from einops import rearrange
def rms_norm_ref(
x,
weight,
bias,
z=None,
eps=1e-6,
group_size=None,
norm_before_gate=True,
upcast=True,
):
dtype = x.dtype
#N = x.shape[-1]
weight = weight.float()
bias = bias.float() if bias is not None else None
if upcast:
x = x.float()
z = z.float() if z is not None else z
if z is not None and not norm_before_gate:
x = x * F.silu(z)
if group_size is None:
rstd = 1 / torch.sqrt((x.square()).mean(dim=-1, keepdim=True) + eps)
out = (x * rstd * weight) + bias if bias is not None else (x * rstd *
weight)
else:
x_group = rearrange(x, "... (g d) -> ... g d", d=group_size)
rstd = 1 / torch.sqrt((x_group.square()).mean(dim=-1, keepdim=True) +
eps)
out = rearrange(x_group * rstd, "... g d -> ... (g d)") * weight
if bias is not None:
out = out + bias
if z is not None and norm_before_gate:
out *= F.silu(z)
return out.to(dtype)
@triton.heuristics({"HAS_BIAS": lambda args: args["B"] is not None})
@triton.heuristics({"HAS_Z": lambda args: args["Z"] is not None})
@triton.jit
def _layer_norm_fwd_1pass_kernel(
X, # pointer to the input
Y, # pointer to the output
W, # pointer to the weights
B, # pointer to the biases
Z, # pointer to the other branch
Mean, # pointer to the mean
Rstd, # pointer to the 1/std
stride_x_row, # how much to increase the pointer when moving by 1 row
stride_y_row,
stride_z_row,
M, # number of rows in X
N, # number of columns in X
eps, # epsilon to avoid division by zero
BLOCK_N: tl.constexpr,
HAS_BIAS: tl.constexpr,
HAS_Z: tl.constexpr,
NORM_BEFORE_GATE: tl.constexpr,
IS_RMS_NORM: tl.constexpr,
):
# Map the program id to the row of X and Y it should compute.
row = tl.program_id(0)
group = tl.program_id(1)
X += row * stride_x_row + group * N
Y += row * stride_y_row + group * N
if HAS_Z:
Z += row * stride_z_row + group * N
if not IS_RMS_NORM:
Mean += group * M
Rstd += group * M
W += group * N
if HAS_BIAS:
B += group * N
# Compute mean and variance
cols = tl.arange(0, BLOCK_N)
x = tl.load(X + cols, mask=cols < N, other=0.0).to(tl.float32)
if HAS_Z and not NORM_BEFORE_GATE:
z = tl.load(Z + cols, mask=cols < N).to(tl.float32)
x *= z * tl.sigmoid(z)
if not IS_RMS_NORM:
mean = tl.sum(x, axis=0) / N
tl.store(Mean + row, mean)
xbar = tl.where(cols < N, x - mean, 0.0)
var = tl.sum(xbar * xbar, axis=0) / N
else:
xbar = tl.where(cols < N, x, 0.0)
var = tl.sum(xbar * xbar, axis=0) / N
rstd = 1 / tl.sqrt(var + eps)
tl.store(Rstd + row, rstd)
# Normalize and apply linear transformation
mask = cols < N
w = tl.load(W + cols, mask=mask).to(tl.float32)
if HAS_BIAS:
b = tl.load(B + cols, mask=mask).to(tl.float32)
x_hat = (x - mean) * rstd if not IS_RMS_NORM else x * rstd
y = x_hat * w + b if HAS_BIAS else x_hat * w
if HAS_Z and NORM_BEFORE_GATE:
z = tl.load(Z + cols, mask=mask).to(tl.float32)
y *= z * tl.sigmoid(z)
# Write output
tl.store(Y + cols, y, mask=mask)
def _layer_norm_fwd(
x,
weight,
bias,
eps,
z=None,
out=None,
group_size=None,
norm_before_gate=True,
is_rms_norm=False,
):
M, N = x.shape
if group_size is None:
group_size = N
assert N % group_size == 0
ngroups = N // group_size
assert x.stride(-1) == 1
if z is not None:
assert z.stride(-1) == 1
assert z.shape == (M, N)
assert weight.shape == (N, )
assert weight.stride(-1) == 1
if bias is not None:
assert bias.stride(-1) == 1
assert bias.shape == (N, )
# allocate output
if out is not None:
assert out.shape == x.shape
else:
out = torch.empty_like(x)
assert out.stride(-1) == 1
mean = (torch.empty((ngroups * M, ), dtype=torch.float32, device=x.device)
if not is_rms_norm else None)
rstd = torch.empty((ngroups * M, ), dtype=torch.float32, device=x.device)
# Less than 64KB per feature: enqueue fused kernel
MAX_FUSED_SIZE = 65536 // x.element_size()
BLOCK_N = min(MAX_FUSED_SIZE, triton.next_power_of_2(group_size))
if group_size > BLOCK_N:
raise RuntimeError(
"This layer norm doesn't support feature dim >= 64KB.")
# heuristics for number of warps
num_warps = min(max(BLOCK_N // 256, 1), 8)
grid = (M, ngroups)
with torch.npu.device(x.device.index):
_layer_norm_fwd_1pass_kernel[grid](
x,
out,
weight,
bias,
z,
mean,
rstd,
x.stride(0),
out.stride(0),
z.stride(0) if z is not None else 0,
M,
group_size,
eps,
BLOCK_N=BLOCK_N,
NORM_BEFORE_GATE=norm_before_gate,
IS_RMS_NORM=is_rms_norm,
num_warps=num_warps,
)
return out, mean, rstd
class LayerNormFn(torch.autograd.Function):
@staticmethod
def forward(
ctx,
x,
weight,
bias,
z=None,
eps=1e-6,
group_size=None,
norm_before_gate=True,
is_rms_norm=False,
):
"""If z is not None, we do norm(x) * silu(z) if norm_before_gate, else norm(x * silu(z))"""
x_shape_og = x.shape
# reshape input data into 2D tensor
x = x.reshape(-1, x.shape[-1])
if x.stride(-1) != 1:
x = x.contiguous()
if z is not None:
assert z.shape == x_shape_og
z = z.reshape(-1, z.shape[-1])
if z.stride(-1) != 1:
z = z.contiguous()
weight = weight.contiguous()
if bias is not None:
bias = bias.contiguous()
y, mean, rstd = _layer_norm_fwd(
x,
weight,
bias,
eps,
z=z,
group_size=group_size,
norm_before_gate=norm_before_gate,
is_rms_norm=is_rms_norm,
)
return y.reshape(x_shape_og)
def layernorm_fn(
x,
weight,
bias,
z=None,
eps=1e-6,
group_size=None,
norm_before_gate=True,
is_rms_norm=False,
):
return LayerNormFn.apply(x, weight, bias, z, eps, group_size,
norm_before_gate, is_rms_norm)
def rmsnorm_fn(x,
weight,
bias,
z=None,
eps=1e-6,
group_size=None,
norm_before_gate=True):
return LayerNormFn.apply(x, weight, bias, z, eps, group_size,
norm_before_gate, True)
class LayerNorm(torch.nn.Module):
def __init__(
self,
hidden_size,
eps=1e-5,
group_size=None,
norm_before_gate=True,
device=None,
dtype=None,
):
"""If group_size is not None, we do GroupNorm with each group having group_size elements.
group_size=None is equivalent to group_size=hidden_size (i.e. there's only 1 group).
"""
factory_kwargs = {"device": device, "dtype": dtype}
super().__init__()
self.eps = eps
self.weight = torch.nn.Parameter(
torch.empty(hidden_size, **factory_kwargs))
self.bias = torch.nn.Parameter(
torch.empty(hidden_size, **factory_kwargs))
self.group_size = group_size
self.norm_before_gate = norm_before_gate
self.reset_parameters()
def reset_parameters(self):
torch.nn.init.ones_(self.weight)
torch.nn.init.zeros_(self.bias)
def forward(self, x, z=None):
"""If z is not None, we do norm(x) * silu(z) if norm_before_gate, else norm(x * silu(z))"""
return layernorm_fn(
x,
self.weight,
self.bias,
z=z,
group_size=self.group_size,
eps=self.eps,
norm_before_gate=self.norm_before_gate,
)
class RMSNormGated(torch.nn.Module):
def __init__(
self,
hidden_size,
eps=1e-5,
group_size=None,
norm_before_gate=True,
device=None,
dtype=None,
):
"""If group_size is not None, we do GroupNorm with each group having group_size elements.
group_size=None is equivalent to group_size=hidden_size (i.e. there's only 1 group).
"""
factory_kwargs = {"device": device, "dtype": dtype}
super().__init__()
self.eps = eps
self.weight = torch.nn.Parameter(
torch.empty(hidden_size, **factory_kwargs))
self.register_parameter("bias", None)
self.group_size = group_size
self.norm_before_gate = norm_before_gate
self.reset_parameters()
def reset_parameters(self):
torch.nn.init.ones_(self.weight)
def forward(self, x, z=None):
"""If z is not None, we do norm(x) * silu(z) if norm_before_gate, else norm(x * silu(z))"""
return rmsnorm_fn(
x,
self.weight,
self.bias,
z=z,
eps=self.eps,
group_size=self.group_size,
norm_before_gate=self.norm_before_gate,
)
@triton.jit
def fused_gdn_gating_kernel(
g,
A_log,
a,
dt_bias,
seq_len,
NUM_HEADS: tl.constexpr,
beta: tl.constexpr,
threshold: tl.constexpr,
BLK_HEADS: tl.constexpr,
):
i_b, i_s, i_d = tl.program_id(0), tl.program_id(1), tl.program_id(2)
head_off = i_d * BLK_HEADS + tl.arange(0, BLK_HEADS)
off = i_b * seq_len * NUM_HEADS + i_s * NUM_HEADS + head_off
mask = head_off < NUM_HEADS
blk_A_log = tl.load(A_log + head_off, mask=mask)
blk_a = tl.load(a + off, mask=mask)
blk_bias = tl.load(dt_bias + head_off, mask=mask)
# If the model is loaded in fp16, without the .float() here, A might be -inf
x = blk_a.to(tl.float32) + blk_bias.to(tl.float32)
softplus_x = tl.where(beta * x <= threshold,
(1 / beta) * tl.log(1 + tl.exp(beta * x)), x)
blk_g = -tl.exp(blk_A_log.to(tl.float32)) * softplus_x
tl.store(g + off, blk_g.to(g.dtype.element_ty), mask=mask)
def fused_gdn_gating(
A_log: torch.Tensor,
a: torch.Tensor,
dt_bias: torch.Tensor,
beta: float = 1.0,
threshold: float = 20.0,
) -> torch.Tensor:
batch, num_heads = a.shape
seq_len = 1
grid = (batch, seq_len, triton.cdiv(num_heads, 8))
g = torch.empty_like(a, dtype=torch.float32)
fused_gdn_gating_kernel[grid](g,
A_log,
a,
dt_bias,
seq_len,
num_heads,
beta,
threshold,
8,
num_warps=1)
return g

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@@ -0,0 +1,403 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# SPDX-FileCopyrightText: Songlin Yang, Yu Zhang
#
# This file contains code copied from the flash-linear-attention project.
# The original source code was licensed under the MIT license and included
# the following copyright notice:
# Copyright (c) 2023-2025, Songlin Yang, Yu Zhang
# ruff: noqa: E501
# mypy: ignore-errors
import os
from typing import Optional
import torch
from vllm.triton_utils import tl, tldevice, triton
if os.environ.get('FLA_USE_FAST_OPS', '0') == '1':
div = tldevice.fast_dividef
exp = tldevice.fast_expf
log = tldevice.fast_logf
log2 = tldevice.fast_log2f
else:
@triton.jit
def div_normal(x, y):
return x / y
div = div_normal
exp = tl.exp
log = tl.log
log2 = tl.log2
@triton.heuristics({
'USE_INITIAL_STATE':
lambda args: args['h0'] is not None,
'IS_VARLEN':
lambda args: args['cu_seqlens'] is not None,
"IS_CONTINUOUS_BATCHING":
lambda args: args['ssm_state_indices'] is not None,
"IS_SPEC_DECODING":
lambda args: args['num_accepted_tokens'] is not None,
})
@triton.jit(do_not_specialize=['N', 'T'])
def fused_recurrent_gated_delta_rule_fwd_kernel(
q,
k,
v,
g,
beta,
o,
h0,
ht,
cu_seqlens,
ssm_state_indices,
num_accepted_tokens,
scale,
N: tl.constexpr, # num of sequences
T: tl.constexpr, # num of tokens
B: tl.constexpr,
H: tl.constexpr,
HV: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
stride_init_state_token: tl.constexpr,
stride_final_state_token: tl.constexpr,
stride_indices_seq: tl.constexpr,
stride_indices_tok: tl.constexpr,
USE_INITIAL_STATE: tl.constexpr, # whether to use initial state
INPLACE_FINAL_STATE: tl.constexpr, # whether to store final state inplace
IS_BETA_HEADWISE: tl.
constexpr, # whether beta is headwise vector or scalar,
USE_QK_L2NORM_IN_KERNEL: tl.constexpr,
IS_VARLEN: tl.constexpr,
IS_CONTINUOUS_BATCHING: tl.constexpr,
IS_SPEC_DECODING: tl.constexpr,
):
i_k, i_v, i_nh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_n, i_hv = i_nh // HV, i_nh % HV
i_h = i_hv // (HV // H)
if IS_VARLEN:
bos, eos = tl.load(cu_seqlens + i_n).to(
tl.int64), tl.load(cu_seqlens + i_n + 1).to(tl.int64)
all = T
T = eos - bos
else:
bos, eos = i_n * T, i_n * T + T
all = B * T
if T == 0:
# no tokens to process for this sequence
return
o_k = i_k * BK + tl.arange(0, BK)
o_v = i_v * BV + tl.arange(0, BV)
# p_q = q + (bos * H + i_h) * K + o_k
# p_k = k + (bos * H + i_h) * K + o_k
# p_v = v + (bos * HV + i_hv) * V + o_v
# if IS_BETA_HEADWISE:
# p_beta = beta + (bos * HV + i_hv) * V + o_v
# else:
# p_beta = beta + bos * HV + i_hv
# p_g = g + bos * HV + i_hv
# p_o = o + ((i_k * all + bos) * HV + i_hv) * V + o_v
mask_k = o_k < K
mask_v = o_v < V
mask_h = mask_k[:, None] & mask_v[None, :]
b_h = tl.zeros([BK, BV], dtype=tl.float32)
if USE_INITIAL_STATE:
if IS_CONTINUOUS_BATCHING:
if IS_SPEC_DECODING:
i_t = tl.load(num_accepted_tokens + i_n).to(tl.int64) - 1
else:
i_t = 0
p_h0 = h0 + tl.load(ssm_state_indices + i_n * stride_indices_seq +
i_t).to(tl.int64) * stride_init_state_token
else:
p_h0 = h0 + bos * HV * K * V
p_h0 = p_h0 + i_hv * K * V + o_k[:, None] * V + o_v[None, :]
b_h += tl.load(p_h0, mask=mask_h, other=0).to(tl.float32)
for i_t in range(0, T):
p_q = q + (bos * H + i_h) * K + o_k + H * K * i_t
p_k = k + (bos * H + i_h) * K + o_k + H * K * i_t
p_v = v + (bos * HV + i_hv) * V + o_v + HV * V * i_t
if IS_BETA_HEADWISE:
p_beta = beta + (bos * HV + i_hv) * V + o_v + HV * V * i_t
else:
p_beta = beta + bos * HV + i_hv + HV * i_t
p_g = g + bos * HV + i_hv + HV * i_t
p_o = o + ((i_k * all + bos) * HV + i_hv) * V + o_v + HV * V * i_t
b_q = tl.load(p_q, mask=mask_k, other=0).to(tl.float32)
b_k = tl.load(p_k, mask=mask_k, other=0).to(tl.float32)
b_v = tl.load(p_v, mask=mask_v, other=0).to(tl.float32)
b_g = tl.load(p_g).to(tl.float32)
if USE_QK_L2NORM_IN_KERNEL:
b_q = b_q / tl.sqrt(tl.sum(b_q * b_q) + 1e-6)
b_k = b_k / tl.sqrt(tl.sum(b_k * b_k) + 1e-6)
b_q = b_q * scale
# [BK, BV]
# b_h *= tl.exp(b_g)
b_h *= exp(b_g)
# [BV]
b_v -= tl.sum(b_h * b_k[:, None], 0)
if IS_BETA_HEADWISE:
b_beta = tl.load(p_beta, mask=mask_v, other=0).to(tl.float32)
else:
b_beta = tl.load(p_beta).to(tl.float32)
b_v *= b_beta
# [BK, BV]
b_h += b_k[:, None] * b_v[None, :]
# [BV]
b_o = tl.sum(b_h * b_q[:, None], 0)
tl.store(p_o, b_o.to(p_o.dtype.element_ty), mask=mask_v)
# keep the states for multi-query tokens
if INPLACE_FINAL_STATE:
p_ht = ht + tl.load(ssm_state_indices + i_n * stride_indices_seq +
i_t).to(tl.int64) * stride_final_state_token
else:
p_ht = ht + (bos + i_t) * stride_final_state_token
p_ht = p_ht + i_hv * K * V + o_k[:, None] * V + o_v[None, :]
tl.store(p_ht, b_h.to(p_ht.dtype.element_ty), mask=mask_h)
# p_q += H * K
# p_k += H * K
# p_o += HV * V
# p_v += HV * V
# p_g += HV
# p_beta += HV * (V if IS_BETA_HEADWISE else 1)
def fused_recurrent_gated_delta_rule_fwd(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
scale: float,
initial_state: torch.Tensor,
inplace_final_state: bool = True,
cu_seqlens: Optional[torch.LongTensor] = None,
ssm_state_indices: Optional[torch.Tensor] = None,
num_accepted_tokens: Optional[torch.Tensor] = None,
use_qk_l2norm_in_kernel: bool = False,
) -> tuple[torch.Tensor, torch.Tensor]:
B, T, H, K, V = *k.shape, v.shape[-1]
HV = v.shape[2]
N = B if cu_seqlens is None else len(cu_seqlens) - 1
BK, BV = triton.next_power_of_2(K), min(triton.next_power_of_2(V), 8)
NK, NV = triton.cdiv(K, BK), triton.cdiv(V, BV)
assert NK == 1, "NK > 1 is not supported yet"
num_stages = 3
num_warps = 1
o = q.new_empty(NK, *v.shape)
if inplace_final_state:
final_state = initial_state
else:
final_state = q.new_empty(T, HV, K, V, dtype=initial_state.dtype)
stride_init_state_token = initial_state.stride(0)
stride_final_state_token = final_state.stride(0)
if ssm_state_indices is None:
stride_indices_seq, stride_indices_tok = 1, 1
elif ssm_state_indices.ndim == 1:
stride_indices_seq, stride_indices_tok = ssm_state_indices.stride(0), 1
else:
stride_indices_seq, stride_indices_tok = ssm_state_indices.stride()
# print("N: ", N)
# print("T: ", T)
# print("B: ", B)
# print("H: ", H)
# print("HV: ", HV)
# print("K: ", K)
# print("V: ", V)
# print("BK: ", BK)
# print("BV: ", BV)
grid = (NK, NV, N * HV)
fused_recurrent_gated_delta_rule_fwd_kernel[grid](
q=q,
k=k,
v=v,
g=g,
beta=beta,
o=o,
h0=initial_state,
ht=final_state,
cu_seqlens=cu_seqlens,
ssm_state_indices=ssm_state_indices,
num_accepted_tokens=num_accepted_tokens,
scale=scale,
N=N,
T=T,
B=B,
H=H,
HV=HV,
K=K,
V=V,
BK=BK,
BV=BV,
stride_init_state_token=stride_init_state_token,
stride_final_state_token=stride_final_state_token,
stride_indices_seq=stride_indices_seq,
stride_indices_tok=stride_indices_tok,
IS_BETA_HEADWISE=beta.ndim == v.ndim,
USE_QK_L2NORM_IN_KERNEL=use_qk_l2norm_in_kernel,
INPLACE_FINAL_STATE=inplace_final_state,
num_warps=num_warps,
num_stages=num_stages,
)
o = o.squeeze(0)
return o, final_state
class FusedRecurrentFunction(torch.autograd.Function):
@staticmethod
def forward(ctx,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
scale: float,
initial_state: torch.Tensor,
inplace_final_state: bool = True,
cu_seqlens: Optional[torch.LongTensor] = None,
ssm_state_indices: Optional[torch.Tensor] = None,
num_accepted_tokens: Optional[torch.Tensor] = None,
use_qk_l2norm_in_kernel: bool = False):
o, final_state = fused_recurrent_gated_delta_rule_fwd(
q=q.contiguous(),
k=k.contiguous(),
v=v.contiguous(),
g=g.contiguous(),
beta=beta.contiguous(),
scale=scale,
initial_state=initial_state,
inplace_final_state=inplace_final_state,
cu_seqlens=cu_seqlens,
ssm_state_indices=ssm_state_indices,
num_accepted_tokens=num_accepted_tokens,
use_qk_l2norm_in_kernel=use_qk_l2norm_in_kernel,
)
return o, final_state
def fused_recurrent_gated_delta_rule(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor = None,
scale: float = None,
initial_state: torch.Tensor = None,
inplace_final_state: bool = True,
cu_seqlens: Optional[torch.LongTensor] = None,
ssm_state_indices: Optional[torch.Tensor] = None,
num_accepted_tokens: Optional[torch.Tensor] = None,
use_qk_l2norm_in_kernel: bool = False,
) -> tuple[torch.Tensor, torch.Tensor]:
r"""
Args:
q (torch.Tensor):
queries of shape `[B, T, H, K]`.
k (torch.Tensor):
keys of shape `[B, T, H, K]`.
v (torch.Tensor):
values of shape `[B, T, HV, V]`.
GVA is applied if `HV > H`.
g (torch.Tensor):
g (decays) of shape `[B, T, HV]`.
beta (torch.Tensor):
betas of shape `[B, T, HV]`.
scale (Optional[int]):
Scale factor for the RetNet attention scores.
If not provided, it will default to `1 / sqrt(K)`. Default: `None`.
initial_state (Optional[torch.Tensor]):
Initial state of shape `[N, HV, K, V]` for `N` input sequences.
For equal-length input sequences, `N` equals the batch size `B`.
Default: `None`.
inplace_final_state: bool:
Whether to store the final state in-place to save memory.
Default: `True`.
cu_seqlens (torch.LongTensor):
Cumulative sequence lengths of shape `[N+1]` used for variable-length training,
consistent with the FlashAttention API.
ssm_state_indices (Optional[torch.Tensor]):
Indices to map the input sequences to the initial/final states.
num_accepted_tokens (Optional[torch.Tensor]):
Number of accepted tokens for each sequence during decoding.
Returns:
o (torch.Tensor):
Outputs of shape `[B, T, HV, V]`.
final_state (torch.Tensor):
Final state of shape `[N, HV, K, V]`.
Examples::
>>> import torch
>>> import torch.nn.functional as F
>>> from einops import rearrange
>>> from fla.ops.gated_delta_rule import fused_recurrent_gated_delta_rule
# inputs with equal lengths
>>> B, T, H, HV, K, V = 4, 2048, 4, 8, 512, 512
>>> q = torch.randn(B, T, H, K, device='cuda')
>>> k = F.normalize(torch.randn(B, T, H, K, device='cuda'), p=2, dim=-1)
>>> v = torch.randn(B, T, HV, V, device='cuda')
>>> g = F.logsigmoid(torch.rand(B, T, HV, device='cuda'))
>>> beta = torch.rand(B, T, HV, device='cuda').sigmoid()
>>> h0 = torch.randn(B, HV, K, V, device='cuda')
>>> o, ht = fused_gated_recurrent_delta_rule(
q, k, v, g, beta,
initial_state=h0,
)
# for variable-length inputs, the batch size `B` is expected to be 1 and `cu_seqlens` is required
>>> q, k, v, g, beta = map(lambda x: rearrange(x, 'b t ... -> 1 (b t) ...'), (q, k, v, g, beta))
# for a batch with 4 sequences, `cu_seqlens` with 5 start/end positions are expected
>>> cu_seqlens = q.new_tensor([0, 2048, 4096, 6144, 8192], dtype=torch.long)
>>> o_var, ht_var = fused_gated_recurrent_delta_rule(
q, k, v, g, beta,
initial_state=h0,
cu_seqlens=cu_seqlens
)
"""
if cu_seqlens is not None and q.shape[0] != 1:
raise ValueError(
f"The batch size is expected to be 1 rather than {q.shape[0]} when using `cu_seqlens`."
f"Please flatten variable-length inputs before processing.")
if scale is None:
scale = k.shape[-1]**-0.5
else:
assert scale > 0, "scale must be positive"
if beta is None:
beta = torch.ones_like(q[..., 0])
o, final_state = FusedRecurrentFunction.apply(
q,
k,
v,
g,
beta,
scale,
initial_state,
inplace_final_state,
cu_seqlens,
ssm_state_indices,
num_accepted_tokens,
use_qk_l2norm_in_kernel,
)
return o, final_state