RWKV-Runner/finetune/lora/v6/fla/ops/retention/parallel.py

340 lines
14 KiB
Python
Raw Normal View History

# -*- coding: utf-8 -*-
# Copyright (c) 2023, Yu Zhang, Songlin Yang
import torch
import triton
import triton.language as tl
from torch.cuda.amp import custom_bwd, custom_fwd
from fla.utils import contiguous
@triton.jit
def parallel_retention_fwd_kernel(
# B: batch_size, H: n_heads, T: seq_len, D: d_head
q, # query [B, H, L, D_head_K]
k, # key [B, H, L, D_head_V]
v, # value [B, H, L, D_head_V]
o, # output [B, H, L, D_head_V]
s_qk_h, # stride size: L * D_head_K
s_qk_t, # stride size: D_head_K
s_qk_d, # stride size: 1
s_vo_h, # stride size: L * D_head_V
s_vo_t, # stride size: D_head_V
s_vo_d, # stride size: 1
B, # batch size
H, # n_heads
T, # seq_len
scale, # D_head_K ** -0.5
BTL: tl.constexpr, # BLOCK SIZE along the sequence dimension for Q
BTS: tl.constexpr, # BLOCK SIZE along the sequence dimension for K/V
BK: tl.constexpr, # BLOCK SIZE along the K dimension
BV: tl.constexpr, # BLOCK SIZE along the V dimension
DK: tl.constexpr, # D_head_K
DV: tl.constexpr, # D_head_V
):
# i_c: chunk index. used for sequence parallelism
i_kv, i_c, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
NV = tl.cdiv(DV, BV)
i_k = i_kv // (NV)
i_v = i_kv % (NV)
i_h = i_bh % H
# decay rate given the head index
b_b = tl.math.log2(1 - tl.math.pow(2, -5 - i_h * 1.0))
# cumulative decay from the end of the chunk
o_k = tl.arange(0, BTS)
d_h = tl.math.exp2((BTS - o_k) * b_b)
p_q = tl.make_block_ptr(q + i_bh * s_qk_h, (T, DK),
(s_qk_t, s_qk_d), (i_c * BTL, i_k * BK), (BTL, BK), (1, 0))
p_k = tl.make_block_ptr(k + i_bh * s_qk_h, (DK, T),
(s_qk_d, s_qk_t), (i_k * BK, 0), (BK, BTS), (0, 1))
p_v = tl.make_block_ptr(v + i_bh * s_vo_h, (T, DV),
(s_vo_t, s_vo_d), (0, i_v * BV), (BTS, BV), (1, 0))
# [BQ, BD] block Q, in the shared memory throughout the whole kernel
b_q = tl.load(p_q, boundary_check=(0, 1))
b_q = (b_q * scale).to(b_q.dtype)
b_o = tl.zeros([BTL, BV], dtype=tl.float32)
# Q block and K block have no overlap
# no need for mask, thereby saving flops
for _ in range(0, i_c * BTL, BTS):
# [BK, BTS]
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BTS, BV]
b_v = tl.load(p_v, boundary_check=(0, 1))
# [BTL, BTS]
b_s = tl.dot(b_q, (b_k), allow_tf32=False) * d_h[None, :]
# [BQ, BD]
b_o = b_o * tl.math.exp2(b_b * BTS)
b_o = b_o + tl.dot(b_s.to(b_v.dtype), b_v, allow_tf32=False)
p_k = tl.advance(p_k, (0, BTS))
p_v = tl.advance(p_v, (BTS, 0))
# # rescale interchunk output
tl.debug_barrier()
o_q = tl.arange(0, BTL)
d_q = tl.math.exp2(tl.arange(0, BTL) * b_b)
b_o *= d_q[:, None]
# # sync threads, easy for compiler to optimize
# tl.debug_barrier()
o_k = tl.arange(0, BTS)
p_k = tl.make_block_ptr(k + i_bh * s_qk_h, (DK, T),
(s_qk_d, s_qk_t), (i_k * BK, i_c * BTL), (BK, BTS), (0, 1))
p_v = tl.make_block_ptr(v + i_bh * s_vo_h, (T, DV),
(s_vo_t, s_vo_d), (i_c * BTL, i_v * BV), (BTS, BV), (1, 0))
# Q block and K block have overlap. masks required
for _ in range(i_c * BTL, (i_c + 1) * BTL, BTS):
# [BK, BTS]
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BTS, BV]
b_v = tl.load(p_v, boundary_check=(0, 1))
# [BTL, BTS]
m_s = o_q[:, None] >= o_k[None, :]
d_s = tl.where(m_s, tl.math.exp2(
(o_q[:, None] - o_k[None, :]) * b_b), 0)
b_s = tl.dot(b_q, b_k, allow_tf32=False) * d_s
# [BTL, BV]
b_o += tl.dot(b_s.to(b_q.dtype), b_v, allow_tf32=False)
p_k = tl.advance(p_k, (0, BTS))
p_v = tl.advance(p_v, (BTS, 0))
o_k += BTS
p_o = tl.make_block_ptr(o + (i_bh + B * H * i_k) * s_vo_h, (T, DV),
(s_vo_t, s_vo_d), (i_c*BTL, i_v*BV), (BTL, BV), (1, 0))
tl.store(p_o, b_o.to(p_o.dtype.element_ty), boundary_check=(0, 1))
@triton.jit
def _parallel_retention_bwd_dq(
i_bh, i_c, i_k, i_v, i_h,
k, v, do, dq, s_qk_h, s_qk_t, s_qk_d, s_vo_h,
s_vo_t, s_vo_d, B, H, T, scale,
BTL: tl.constexpr, BTS: tl.constexpr, BK: tl.constexpr, BV: tl.constexpr,
DK: tl.constexpr, DV: tl.constexpr,
):
p_do = tl.make_block_ptr(do + i_bh * s_vo_h, (T, DV), (s_vo_t, s_vo_d),
(i_c * BTL, i_v * BV), (BTL, BV), (1, 0))
b_do = tl.load(p_do, boundary_check=(0, 1))
b_dq = tl.zeros([BTL, BK], dtype=tl.float32)
p_k = tl.make_block_ptr(k + i_bh * s_qk_h, (T, DK),
(s_qk_t, s_qk_d), (0, i_k * BK), (BTS, BK), (1, 0))
p_v = tl.make_block_ptr(v + i_bh * s_vo_h, (DV, T),
(s_vo_d, s_vo_t), (i_v * BV, 0), (BV, BTS), (0, 1))
# decay rate given the head index
b_b = tl.math.log2(1 - tl.math.pow(2, -5 - i_h * 1.0))
# overall decay rate for an entire block
d_b = tl.math.exp2(b_b * BTS)
# cumulative decay from the end of the chunk
d_h = tl.math.exp2((BTS - tl.arange(0, BTS)) * b_b)
for _ in range(0, i_c * BTL, BTS):
# [BTS, BK]
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BV, BTS]
b_v = tl.load(p_v, boundary_check=(0, 1))
# [BTL, BTS]
b_ds = tl.dot(b_do, b_v, allow_tf32=False) * d_h[None, :]
# [BQ, BD]
b_dq *= d_b
b_dq += tl.dot(b_ds.to(b_v.dtype), b_k, allow_tf32=False)
p_k = tl.advance(p_k, (BTS, 0))
p_v = tl.advance(p_v, (0, BTS))
b_dq *= tl.math.exp2(tl.arange(0, BTL) * b_b)[:, None] * scale
o_q = tl.arange(0, BTL)
o_k = tl.arange(0, BTS)
p_k = tl.make_block_ptr(k + i_bh * s_qk_h, (T, DK),
(s_qk_t, s_qk_d), (i_c * BTL, i_k * BK), (BTS, BK), (1, 0))
p_v = tl.make_block_ptr(v + i_bh * s_vo_h, (DV, T),
(s_vo_d, s_vo_t), (i_v * BV, i_c * BTL), (BV, BTS), (0, 1))
# Q block and K block have overlap. masks required
for _ in range(i_c * BTL, (i_c + 1) * BTL, BTS):
# [BTS, BK]
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BV, BTS]
b_v = tl.load(p_v, boundary_check=(0, 1))
# [BTL, BTS]
m_s = o_q[:, None] >= o_k[None, :]
d_s = tl.where(m_s, tl.math.exp2(
(o_q[:, None] - o_k[None, :]) * b_b), 0)
b_ds = tl.dot(b_do, b_v, allow_tf32=False) * d_s * scale
# [BTL, BK]
b_dq += tl.dot(b_ds.to(b_k.dtype), b_k, allow_tf32=False)
p_k = tl.advance(p_k, (BTS, 0))
p_v = tl.advance(p_v, (0, BTS))
o_k += BTS
p_dq = tl.make_block_ptr(dq + (i_bh + B * H * i_v) * s_qk_h, (T, DK),
(s_qk_t, s_qk_d), (i_c*BTL, i_k*BK), (BTL, BK), (1, 0))
tl.store(p_dq, b_dq.to(p_dq.dtype.element_ty), boundary_check=(0, 1))
return
@triton.jit
def _parallel_retention_bwd_dkv(
i_bh, i_c, i_k, i_v, i_h,
q, k, v, do, dk, dv, s_qk_h, s_qk_t, s_qk_d, s_vo_h,
s_vo_t, s_vo_d, B, H, T, scale,
BTL: tl.constexpr, BTS: tl.constexpr, BK: tl.constexpr, BV: tl.constexpr,
DK: tl.constexpr, DV: tl.constexpr,
):
# no overlap. no need for mask.
b_b = tl.math.log2(1 - tl.math.pow(2, -5 - i_h * 1.0))
# overall decay rate for an entire block
d_b = tl.math.exp2(b_b * BTS)
# compute dk dv
p_k = tl.make_block_ptr(k + i_bh * s_qk_h, (T, DK), (s_qk_t, s_qk_d),
(i_c * BTL, i_k * BK), (BTL, BK), (1, 0))
p_v = tl.make_block_ptr(v + i_bh * s_vo_h, (T, DV), (s_vo_t, s_vo_d),
(i_c * BTL, i_v * BV), (BTL, BV), (1, 0))
b_k, b_v = tl.load(p_k, boundary_check=(0, 1)), tl.load(
p_v, boundary_check=(0, 1))
b_dk, b_dv = tl.zeros([BTL, BK], dtype=tl.float32), tl.zeros(
[BTL, BV], dtype=tl.float32)
d_h = tl.math.exp2((BTL - tl.arange(0, BTL)) * b_b)
b_kd = (b_k * d_h[:, None]).to(b_k.dtype)
d_q = tl.math.exp2(tl.arange(0, BTS) * b_b)
for i in range((tl.cdiv(T, BTS) * BTS)-BTS, (i_c + 1) * BTL - BTS, -BTS):
p_q = tl.make_block_ptr(
q + i_bh * s_qk_h, (DK, T), (s_qk_d, s_qk_t), (i_k * BK, i), (BK, BTS), (0, 1))
p_do = tl.make_block_ptr(
do + i_bh * s_vo_h, (DV, T), (s_vo_d, s_vo_t), (i_v * BV, i), (BV, BTS), (0, 1))
b_q = tl.load(p_q, boundary_check=(0, 1)) # [BK, BTS]
b_do = tl.load(p_do, boundary_check=(0, 1)) # [BV, BTS]
b_do = (b_do * d_q[None, :]).to(b_do.dtype)
b_dv *= d_b
b_s = tl.dot(b_kd.to(b_q.dtype), b_q, allow_tf32=False) # [BTL, BTS]
b_dv += tl.dot(b_s.to(b_q.dtype), tl.trans(b_do), allow_tf32=False)
b_dk *= d_b
b_ds = tl.dot(b_v, b_do, allow_tf32=False)
b_dk += tl.dot(b_ds.to(b_q.dtype), tl.trans(b_q), allow_tf32=False)
b_dk *= d_h[:, None] * scale
b_dv *= scale
tl.debug_barrier()
o_q, o_k = tl.arange(0, BTS), tl.arange(0, BTL)
for i in range(i_c*BTL, (i_c+1)*BTL, BTS):
p_q = tl.make_block_ptr(
q + i_bh * s_qk_h, (DK, T), (s_qk_d, s_qk_t), (i_k * BK, i), (BK, BTS), (0, 1))
p_do = tl.make_block_ptr(
do + i_bh * s_vo_h, (DV, T), (s_vo_d, s_vo_t), (i_v * BV, i), (BV, BTS), (0, 1))
b_q = tl.load(p_q, boundary_check=(0, 1)) # [BD, BQ]
b_do = tl.load(p_do, boundary_check=(0, 1))
# [BK, BQ]
m_s = o_k[:, None] <= o_q[None, :]
d_s = tl.where(m_s, tl.math.exp2(
(-o_k[:, None] + o_q[None, :]) * b_b.to(tl.float32)), 0) * scale
b_s = tl.dot(b_k, b_q, allow_tf32=False) * d_s
b_ds = tl.dot(b_v, b_do, allow_tf32=False) * d_s
# [BK, BD]
b_dk += tl.dot(b_ds.to(b_q.dtype), tl.trans(b_q), allow_tf32=False)
b_dv += tl.dot(b_s.to(b_q.dtype), tl.trans(b_do), allow_tf32=False)
o_q += BTS
p_dk = tl.make_block_ptr(dk + (i_bh + B * H * i_v) * s_qk_h,
(T, DK), (s_qk_t, s_qk_d), (i_c*BTL, i_k*BK), (BTL, BK), (1, 0))
p_dv = tl.make_block_ptr(dv + (i_bh + B * H * i_k) * s_vo_h,
(T, DV), (s_vo_t, s_vo_d), (i_c*BTL, i_v*BV), (BTL, BV), (1, 0))
tl.store(p_dk, b_dk.to(p_dk.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dv, b_dv.to(p_dv.dtype.element_ty), boundary_check=(0, 1))
return
@triton.jit
def parallel_retention_bwd_kernel(
q, k, v, do, dq, dk, dv, s_qk_h, s_qk_t, s_qk_d, s_vo_h,
s_vo_t, s_vo_d, B, H, T, scale,
BTL: tl.constexpr, BTS: tl.constexpr, BK: tl.constexpr, BV: tl.constexpr,
DK: tl.constexpr, DV: tl.constexpr,
):
i_kv, i_c, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
NV = tl.cdiv(DV, BV)
i_k = i_kv // (NV)
i_v = i_kv % (NV)
i_h = i_bh % H
_parallel_retention_bwd_dq(
i_bh, i_c, i_k, i_v, i_h,
k, v, do, dq, s_qk_h, s_qk_t, s_qk_d, s_vo_h,
s_vo_t, s_vo_d, B, H, T, scale, BTL=BTL, BTS=BTS, BK=BK, BV=BV, DK=DK, DV=DV
)
tl.debug_barrier()
_parallel_retention_bwd_dkv(
i_bh, i_c, i_k, i_v, i_h,
q, k, v, do, dk, dv, s_qk_h, s_qk_t, s_qk_d, s_vo_h,
s_vo_t, s_vo_d, B, H, T, scale, BTL, BTS, BK, BV, DK, DV
)
class ParallelRetentionFunction(torch.autograd.Function):
@staticmethod
@contiguous
@custom_fwd
def forward(ctx, q, k, v):
BTL, BTS = 128, 32
assert BTL % BTS == 0
BK = min(128, triton.next_power_of_2(k.shape[-1]))
BV = min(128, triton.next_power_of_2(v.shape[-1]))
batch_size, n_heads, seq_len, d_head_qk = q.shape
d_head_v = v.shape[-1]
num_stages = 3 if d_head_qk <= 64 else 2
num_warps = 4
NK = triton.cdiv(d_head_qk, BK)
NV = triton.cdiv(d_head_v, BV)
grid = (NK * NV, triton.cdiv(seq_len, BTL), batch_size * n_heads)
scale = d_head_qk ** -0.5
o = torch.empty(NK, batch_size, n_heads, seq_len,
d_head_v, dtype=q.dtype, device=q.device)
parallel_retention_fwd_kernel[grid](
q, k, v, o,
q.stride(1), q.stride(2), q.stride(3),
v.stride(1), v.stride(2), v.stride(3),
batch_size, n_heads, seq_len, scale,
BTL=BTL, BTS=BTS, BK=BK, BV=BV, DK=d_head_qk, DV=d_head_v,
num_warps=num_warps,
num_stages=num_stages
)
ctx.save_for_backward(q, k, v)
return o.sum(0).to(q.dtype)
@staticmethod
@contiguous
@custom_bwd
def backward(ctx, do):
q, k, v = ctx.saved_tensors
BTL, BTS = 64, 32
assert BTL % BTS == 0
BK = min(128, triton.next_power_of_2(k.shape[-1]))
BV = min(128, triton.next_power_of_2(v.shape[-1]))
batch_size, n_heads, seq_len, d_head_qk = q.shape
d_head_v = v.shape[-1]
num_stages = 3 if d_head_qk <= 64 else 2
num_warps = 4
NK = triton.cdiv(d_head_qk, BK)
NV = triton.cdiv(d_head_v, BV)
grid = (NK * NV, triton.cdiv(seq_len, BTL), batch_size * n_heads)
scale = d_head_qk ** -0.5
dq = torch.empty(NV, batch_size, n_heads, seq_len,
d_head_qk, dtype=q.dtype, device=q.device)
dk = torch.empty(NV, batch_size, n_heads, seq_len,
d_head_qk, dtype=q.dtype, device=q.device)
dv = torch.empty(NK, batch_size, n_heads, seq_len,
d_head_v, dtype=q.dtype, device=q.device)
parallel_retention_bwd_kernel[grid](
q, k, v, do, dq, dk, dv,
q.stride(1), q.stride(2), q.stride(3),
v.stride(1), v.stride(2), v.stride(3),
batch_size, n_heads, seq_len, scale,
BTL=BTL, BTS=BTS, BK=BK, BV=BV, DK=d_head_qk, DV=d_head_v,
num_warps=num_warps,
num_stages=num_stages
)
return dq.sum(0).to(q.dtype), dk.sum(0).to(k.dtype), dv.sum(0).to(v.dtype)
parallel_retention = ParallelRetentionFunction.apply