from typing import Optional, Tuple
import torch
import triton
import triton.language as tl
from .utils import prepare_chunk_indices, exp, prepare_chunk_offsets
@triton.heuristics({
'USE_G': lambda args: args['g'] is not None,
'USE_G_GAMMA': lambda args: args['g_gamma'] is not None,
'USE_DW': lambda args: args['dw'] is not None,
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.jit(do_not_specialize=['T'])
def chunk_bwd_kernel_dqkwg(
q,
k,
v,
h,
g,
g_gamma,
do,
dh,
dq,
dk,
dg,
w,
dv,
dw,
cu_seqlens,
chunk_indices,
scale,
B: tl.constexpr,
T,
H: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
USE_G: tl.constexpr,
USE_G_GAMMA: tl.constexpr,
USE_DW: tl.constexpr,
IS_VARLEN: tl.constexpr,
gdiff,
):
i_t, i_b = tl.program_id(0), tl.program_id(1)
T_max = T
if IS_VARLEN:
i_tg = i_t
i_n, i_t = tl.load(chunk_indices + i_t * 2).to(tl.int32), tl.load(chunk_indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(cu_seqlens + i_n + 1).to(tl.int32)
total = B * T_max
T = eos - bos
else:
NT = tl.cdiv(T, BT)
i_tg = i_b * NT + i_t
bos, eos = i_b * T, i_b * T + T
total = B * T_max
NK = tl.cdiv(K, BK)
for i_k in range(NK):
if USE_G:
dg_k = dg + i_k * total * H
for i_h in range(H):
v_h = v + (bos * H + i_h) * V
do_h = do + (bos * H + i_h) * V
h_h = h + (i_tg * H + i_h).to(tl.int64) * K * V
dh_h = dh + (i_tg * H + i_h).to(tl.int64) * K * V
q_h = q + (bos * H + i_h) * K
k_h = k + (bos * H + i_h) * K
dq_h = dq + (bos * H + i_h) * K
dk_h = dk + (bos * H + i_h) * K
if USE_DW:
w_h = w + (bos * H + i_h) * K
dw_h = dw + (bos * H + i_h) * K
dv_h = dv + (bos * H + i_h) * V
if USE_G:
if IS_VARLEN:
dg_h = dg_k + i_h * T_max + bos
g_h = g + i_h * T_max + bos
else:
dg_h = dg_k + (i_b * H + i_h) * T_max
g_h = g + (i_b * H + i_h) * T_max
b_dg_last = tl.zeros([1, ], dtype=tl.float32)
if USE_G_GAMMA:
b_gamma = tl.load(g_gamma + i_h)
b_g = b_gamma * (tl.arange(0, BT) + 1)
b_g_last = b_gamma * min(BT, T - i_t * BT)
b_dq = tl.zeros([BT, BK], dtype=tl.float32)
b_dk = tl.zeros([BT, BK], dtype=tl.float32)
b_ds = tl.zeros([BT, BT], dtype=tl.float32)
b_dw = tl.zeros([BT, BK], dtype=tl.float32) if USE_DW else None
for i_v in range(tl.cdiv(V, BV)):
p_v = tl.make_block_ptr(v_h, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_do = tl.make_block_ptr(do_h, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_h = tl.make_block_ptr(h_h, (V, K), (1, V), (i_v * BV, i_k * BK), (BV, BK), (0, 1))
p_dh = tl.make_block_ptr(dh_h, (V, K), (1, V), (i_v * BV, i_k * BK), (BV, BK), (0, 1))
b_v = tl.load(p_v, boundary_check=(0, 1))
b_do = tl.load(p_do, boundary_check=(0, 1))
b_h = tl.load(p_h, boundary_check=(0, 1))
b_dh = tl.load(p_dh, boundary_check=(0, 1))
if USE_G:
b_dg_last += (tl.sum(b_h * b_dh))
b_ds += tl.dot(b_do, tl.trans(b_v))
b_dq += tl.dot(b_do, b_h.to(b_do.dtype))
b_dk += tl.dot(b_v, b_dh.to(b_v.dtype))
if USE_DW:
p_dv = tl.make_block_ptr(dv_h, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
b_dv = tl.load(p_dv, boundary_check=(0, 1))
b_dw += tl.dot(b_dv.to(b_v.dtype), b_h.to(b_v.dtype))
if USE_DW:
p_dw = tl.make_block_ptr(dw_h, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
tl.store(p_dw, -b_dw.to(p_dw.dtype.element_ty), boundary_check=(0, 1))
tl.debug_barrier()
p_q = tl.make_block_ptr(q_h, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_k = tl.make_block_ptr(k_h, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
b_q = tl.load(p_q, boundary_check=(0, 1))
b_k = tl.load(p_k, boundary_check=(0, 1))
p_dq = tl.make_block_ptr(dq_h, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_dk = tl.make_block_ptr(dk_h, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
o_t = i_t * BT + tl.arange(0, BT)
m_t = o_t < T
m_A = (o_t[:, None] >= o_t[None, :]) & (m_t[:, None] & m_t)
if USE_G:
b_dg = tl.zeros([BT, ], dtype=tl.float32)
p_g = tl.make_block_ptr(g_h, (T,), (1,), (i_t * BT,), (BT,), (0,))
b_g = tl.load(p_g, boundary_check=(0,))
b_g_last = tl.load(g_h + (min(i_t * BT + BT, T) - 1) * 1)
b_dg_last *= tl.exp(b_g_last)
b_dq = b_dq * tl.exp(b_g)[:, None] * scale
b_dg += tl.sum(b_dq * b_q, axis=1)
b_dk = b_dk * tl.where(m_t, tl.exp(-b_g + b_g_last), 0)[:, None]
b_dg -= tl.sum(b_k * b_dk, axis=1)
b_dg_last += tl.sum(b_dk * b_k)
if IS_VARLEN:
b_ds = tl.where(m_A, b_ds * exp(b_g[:, None] - b_g[None, :]), 0) * scale
else:
p_gdiff = tl.make_block_ptr(gdiff + i_b * H * NT * BT * BT + i_h * NT * BT * BT + i_t * BT * BT,
(BT, BT), (BT, 1), (0, 0), (BT, BT), (1, 0))
gdiff_ = tl.load(p_gdiff)
b_ds = b_ds * gdiff_ * scale
b_ds2 = b_ds * tl.dot(b_q, tl.trans(b_k))
b_dg += tl.sum(b_ds2, axis=1)
b_dg -= tl.sum(b_ds2, axis=0)
b_ds = b_ds.to(b_k.dtype)
b_dq += tl.dot(b_ds, b_k)
b_dk += tl.dot(tl.trans(b_ds), b_q)
p_dg = tl.make_block_ptr(dg_h, (T,), (1,), (i_t * BT,), (BT,), (0,))
last_index_local = min(BT, T - i_t * BT) - 1
if last_index_local >= 0:
is_last_mask = tl.arange(0, BT) == last_index_local
b_dg = tl.where(is_last_mask, b_dg + b_dg_last, b_dg)
else:
pass
tl.store(p_dq, b_dq.to(p_dq.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dk, b_dk.to(p_dk.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dg, b_dg.to(p_dg.dtype.element_ty), boundary_check=(0,))
elif USE_G_GAMMA:
b_dq = b_dq * exp(b_g)[:, None] * scale
b_dk = b_dk * tl.where(m_t, exp(-b_g + b_g_last), 0)[:, None]
b_ds = tl.where(m_A, b_ds * exp(b_g[:, None] - b_g[None, :]), 0) * scale
b_ds = b_ds.to(b_k.dtype)
b_dq += tl.dot(b_ds, b_k)
b_dk += tl.dot(tl.trans(b_ds), b_q)
tl.store(p_dq, b_dq.to(p_dq.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dk, b_dk.to(p_dk.dtype.element_ty), boundary_check=(0, 1))
else:
b_ds = tl.where(m_A, b_ds, 0)
b_ds = b_ds.to(b_k.dtype)
b_dq += tl.dot(b_ds, b_k)
b_dk += tl.dot(tl.trans(b_ds), b_q) * scale
b_dq *= scale
tl.store(p_dq, b_dq.to(p_dq.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dk, b_dk.to(p_dk.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({
'USE_G': lambda args: args['g'] is not None,
'USE_G_GAMMA': lambda args: args['g_gamma'] is not None,
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.jit(do_not_specialize=['T'])
def chunk_bwd_kernel_dv_local(
q,
k,
g,
g_gamma,
do,
dv,
cu_seqlens,
chunk_indices,
scale,
T,
H: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
USE_G: tl.constexpr,
USE_G_GAMMA: tl.constexpr,
IS_VARLEN: tl.constexpr,
):
i_t, i_b = tl.program_id(0), tl.program_id(1)
T_max = T
if IS_VARLEN:
i_n, i_t = tl.load(chunk_indices + i_t * 2).to(tl.int32), tl.load(chunk_indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(cu_seqlens + i_n + 1).to(tl.int32)
T = eos - bos
else:
bos, eos = i_b * T, i_b * T + T
for i_h in range(H):
offset_kh = (bos * H + i_h) * K
offset_vh = (bos * H + i_h) * V
b_A = tl.zeros([BT, BT], dtype=tl.float32)
for i_k in range(tl.cdiv(K, BK)):
p_k = tl.make_block_ptr(k + offset_kh, (T, K), (H * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_q = tl.make_block_ptr(q + offset_kh, (K, T), (1, H * K), (i_k * BK, i_t * BT), (BK, BT), (0, 1))
b_q = tl.load(p_q, boundary_check=(0, 1))
b_k = tl.load(p_k, boundary_check=(0, 1))
b_A += tl.dot(b_k, b_q)
if USE_G:
if IS_VARLEN:
offset_g = i_h * T_max + bos
else:
offset_g = i_b * H * T_max + i_h * T_max
p_g = tl.make_block_ptr(g + offset_g, (T,), (1,), (i_t * BT,), (BT,), (0,))
b_g = tl.load(p_g, boundary_check=(0,))
if USE_G_GAMMA:
b_gamma = tl.load(g_gamma + i_h)
b_g = b_gamma * (tl.arange(0, BT) + 1)
o_t = i_t * BT + tl.arange(0, BT)
m_t = o_t < T
m_A = (o_t[:, None] <= o_t[None, :]) & (m_t[:, None] & m_t)
if USE_G:
b_A = tl.where(m_A, b_A * tl.exp(b_g[None, :] - b_g[:, None]) * scale, 0).to(do.dtype.element_ty)
else:
b_A = tl.where(m_A, b_A * scale, 0).to(do.dtype.element_ty)
for i_v in range(tl.cdiv(V, BV)):
p_do = tl.make_block_ptr(do + offset_vh, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dv = tl.make_block_ptr(dv + offset_vh, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
b_do = tl.load(p_do, boundary_check=(0, 1))
b_dv = tl.dot(b_A.to(b_do.dtype), b_do)
tl.store(p_dv, b_dv.to(p_dv.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({
'USE_G': lambda args: args['g'] is not None,
'USE_G_GAMMA': lambda args: args['g_gamma'] is not None,
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None
})
@triton.jit(do_not_specialize=['T'])
def chunk_fwd_kernel_o(
q,
k,
v,
h,
g,
g_gamma,
o,
cu_seqlens,
chunk_offsets,
scale,
T,
H: tl.constexpr,
N: tl.constexpr,
Hg: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
USE_G: tl.constexpr,
USE_G_GAMMA: tl.constexpr,
IS_VARLEN: tl.constexpr,
):
T_max = T
for i_v in range(tl.cdiv(V, BV)):
for i_n in range(N):
if IS_VARLEN:
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(
cu_seqlens + i_n + 1
).to(tl.int32)
T = eos - bos
NT = tl.cdiv(T, BT)
boh = tl.load(chunk_offsets + i_n).to(tl.int64)
else:
bos, eos = i_n * T, i_n * T + T
NT = tl.cdiv(T, BT)
boh = i_n * NT
core_id = tl.program_id(0)
total_cores = tl.num_programs(0)
base_chunks_per_pid = NT // total_cores
remainder = NT % total_cores
if core_id < remainder:
chunks_this_pid = base_chunks_per_pid + 1
start_idx = core_id * chunks_this_pid
else:
chunks_this_pid = base_chunks_per_pid
start_idx = core_id * base_chunks_per_pid + remainder
for i_h in range(0, H):
q_offset = (bos * Hg + i_h // (H // Hg)) * K
k_offset = (bos * Hg + i_h // (H // Hg)) * K
v_offset = (bos * H + i_h) * V
o_offset = (bos * H + i_h) * V
for i_t in range(start_idx, start_idx + chunks_this_pid):
i_tg = boh + i_t
h_base = h + (i_tg * H + i_h).to(tl.int64) * K * V
b_o = tl.zeros([BT, BV], dtype=tl.float32)
b_A = tl.zeros([BT, BT], dtype=tl.float32)
for i_k in range(tl.cdiv(K, BK)):
p_q = tl.make_block_ptr(
q + q_offset, (T, K), (Hg * K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0)
)
p_k = tl.make_block_ptr(
k + k_offset, (K, T), (1, Hg * K), (i_k * BK, i_t * BT), (BK, BT), (0, 1)
)
p_h = tl.make_block_ptr(
h_base, (K, V), (V, 1), (i_k * BK, i_v * BV), (BK, BV), (1, 0)
)
b_q = tl.load(p_q, boundary_check=(0, 1))
b_k = tl.load(p_k, boundary_check=(0, 1))
b_h = tl.load(p_h, boundary_check=(0, 1))
b_o += tl.dot(b_q, b_h)
b_A += tl.dot(b_q, b_k)
if USE_G:
if IS_VARLEN:
p_g = tl.make_block_ptr(g + bos + i_h * T_max, (T,), (1,), (i_t * BT,), (BT,), (0,))
else:
p_g = tl.make_block_ptr(g + bos * H + i_h * T_max, (T,), (1,), (i_t * BT,), (BT,), (0,))
b_g = tl.load(p_g, boundary_check=(0,))
b_o = b_o * exp(b_g)[:, None]
b_A = b_A * exp(b_g[:, None] - b_g[None, :])
if USE_G_GAMMA:
b_gamma = tl.load(g_gamma + i_h)
b_g = b_gamma * (tl.arange(0, BT) + 1)
o_i = tl.arange(0, BT)
m_A = o_i[:, None] >= o_i[None, :]
b_A = tl.where(m_A, b_A, 0)
p_v = tl.make_block_ptr(
v + v_offset, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0)
)
p_o = tl.make_block_ptr(
o + o_offset, (T, V), (H * V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0)
)
b_v = tl.load(p_v, boundary_check=(0, 1))
b_o = b_o * scale + tl.dot(b_A.to(b_v.dtype), b_v) * scale
tl.store(p_o, b_o.to(p_o.dtype.element_ty), boundary_check=(0, 1))
def chunk_bwd_dqkwg(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
do: torch.Tensor,
h: torch.Tensor,
dh: torch.Tensor,
g: Optional[torch.Tensor] = None,
g_gamma: Optional[torch.Tensor] = None,
dv: Optional[torch.Tensor] = None,
w: Optional[torch.Tensor] = None,
cu_seqlens: Optional[torch.LongTensor] = None,
chunk_size: int = 64,
scale: float = 1.0,
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
B, T, H, K, V = *k.shape, v.shape[-1]
BT = min(chunk_size, max(16, triton.next_power_of_2(T)))
chunk_indices = prepare_chunk_indices(cu_seqlens, BT) if cu_seqlens is not None else None
NT = triton.cdiv(T, BT) if cu_seqlens is None else len(chunk_indices)
BK = 128 if cu_seqlens is None else 64
BV = 64
NK = triton.cdiv(K, BK)
dq = torch.empty_like(q)
dk = torch.empty_like(k)
g = g.transpose(1, 2).contiguous()
dg = torch.empty(NK, *g.shape, dtype=torch.float32, device=g.device) if g is not None else None
dw = torch.empty_like(w) if w is not None else None
grid = (NT, B)
if cu_seqlens is None:
if NT * BT == T:
g_ = g.reshape(B, H, NT, BT)
g_diff = g_[:, :, :, :, None] - g_[:, :, :, None, :]
g_diff = g_diff.clamp(-60, 60).exp()
g_diff[:, :, :] *= torch.tril(torch.ones(BT, BT), diagonal=0).to(g.device)
else:
diff = NT * BT - T
g_ = torch.cat((g, torch.zeros(B, H, diff).to(g.device)), dim=-1).reshape(B, H, NT, BT)
g_diff = g_[:, :, :, :, None] - g_[:, :, :, None, :]
g_diff = g_diff.clamp(-60, 60).exp()
g_diff[:, :, :] *= torch.tril(torch.ones(BT, BT), diagonal=0).to(g.device)
bias = torch.arange(0, BT).to(g.device)
o_t = (NT - 1) * BT + bias
m_t = o_t < T
m_A = (m_t[:, None] & m_t)
g_diff[:, :, -1] *= m_A
else:
g_diff = None
chunk_bwd_kernel_dqkwg[grid](
q=q,
k=k,
v=v,
h=h,
g=g,
g_gamma=g_gamma,
do=do,
dh=dh,
dv=dv,
w=w,
dw=dw,
dq=dq,
dk=dk,
dg=dg,
cu_seqlens=cu_seqlens,
chunk_indices=chunk_indices,
scale=scale,
B=B,
T=T,
H=H,
K=K,
V=V,
BT=BT,
BK=BK,
BV=BV,
gdiff=g_diff,
)
if dg is not None:
dg = dg.sum(0)
dg = dg.transpose(1, 2).contiguous()
return dq, dk, dw, dg
def chunk_bwd_dv_local(
q: torch.Tensor,
k: torch.Tensor,
do: torch.Tensor,
g: Optional[torch.Tensor] = None,
g_gamma: Optional[torch.Tensor] = None,
scale: float = None,
cu_seqlens: Optional[torch.LongTensor] = None,
chunk_size: int = 64
) -> torch.Tensor:
B, T, H, K, V = *k.shape, do.shape[-1]
BT = min(chunk_size, max(16, triton.next_power_of_2(T)))
chunk_indices = prepare_chunk_indices(cu_seqlens, BT) if cu_seqlens is not None else None
BK = 128
BV = 128
NT = triton.cdiv(T, BT) if cu_seqlens is None else len(chunk_indices)
g = g.transpose(1, 2).contiguous()
dv = torch.empty_like(do)
grid = (NT, B)
chunk_bwd_kernel_dv_local[grid](
q=q,
k=k,
g=g,
g_gamma=g_gamma,
do=do,
dv=dv,
cu_seqlens=cu_seqlens,
chunk_indices=chunk_indices,
scale=scale,
T=T,
H=H,
K=K,
V=V,
BT=BT,
BK=BK,
BV=BV,
)
return dv
def chunk_fwd_o(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
h: torch.Tensor,
g: Optional[torch.Tensor] = None,
g_gamma: Optional[torch.Tensor] = None,
scale: Optional[float] = None,
cu_seqlens: Optional[torch.LongTensor] = None,
chunk_size: int = 64
) -> torch.Tensor:
B, T, Hg, K, V = *q.shape, v.shape[-1]
H = v.shape[-2]
BT = min(chunk_size, max(16, triton.next_power_of_2(T)))
chunk_indices = (
prepare_chunk_indices(cu_seqlens, BT) if cu_seqlens is not None else None
)
NT = triton.cdiv(T, BT) if cu_seqlens is None else len(chunk_indices)
if scale is None:
scale = k.shape[-1] ** -0.5
o = torch.empty_like(v)
if cu_seqlens is None:
N, chunk_offsets = B, None
else:
N, chunk_offsets = (
len(cu_seqlens) - 1,
prepare_chunk_offsets(cu_seqlens, BT),
)
def grid(meta):
return (triton.cdiv(V, meta["BV"]), N * H)
g = g.transpose(1, 2).contiguous()
h = h.contiguous()
CV_kernel_num = 24
chunk_fwd_kernel_o[(CV_kernel_num,)](
q,
k,
v,
h,
g,
g_gamma,
o,
cu_seqlens,
chunk_offsets,
scale,
T=T,
H=H,
N=N,
Hg=Hg,
K=K,
V=V,
BT=BT,
BK=128,
BV=128,
)
return o
bwd_chunk_dqkwg = chunk_bwd_dqkwg
bwd_chunk_dv_local = chunk_bwd_dv_local
