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2026-01-19 10:38:50 +08:00

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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""
Utilities for Punica kernel construction.
"""
from vllm.triton_utils import tl, triton
@triton.jit
def mm_k(
a_ptr,
b_ptr,
ak_stride,
bk_stride,
offset_k,
K: tl.constexpr,
BLOCK_M: tl.constexpr,
BLOCK_N: tl.constexpr,
BLOCK_K: tl.constexpr,
EVEN_K: tl.constexpr,
SPLIT_K: tl.constexpr,
CAST_TYPE: tl.constexpr,
b_dtype: tl.constexpr,
USE_GDC: tl.constexpr,
base_k,
):
"""
Given a_ptr and b_ptr, that identify the rows of A (m x k) and columns of
B (k x n), iterate, through the K dimension to compute the partial/complete
matrix block product.
If SPLIT_K == 1, the output m x n product is complete.
If SPLIT_K > 1, the thread block computes partial outputs. The partial
outputs are then atomically summed in the caller code.
Args:
a_ptr: Array of pointers, identifying rows of A
b_ptr: Array of pointers, identifying columns of B
ak_stride: K dimension stride of the A matrix
bk_stride: K dimension stride of the B matrix
K: Length of the K dimension
BLOCK_M: M dimension of the output block m x n
BLOCK_N: N dimension of the output block m x n
BLOCK_K: K dimension atom
EVEN_K: True if the blocks of A and B can be loaded without any
masking.
SPLIT_K: Parameter signifying parallelism in the K dimension.
CAST_TYPE: if True, cast the values from the A matrix to the B
matrix dtype.
b_dtype: datatype of the B matrix
USE_GDC: Whether to use PDL. True indicates use.
base_k: Base offset along K dimension for current SPLIT_K group
"""
accumulator = tl.zeros((BLOCK_M, BLOCK_N), dtype=tl.float32)
# Step size along K for each iteration
STEP_K = BLOCK_K * SPLIT_K
# Total number of iterations (compile-time constant)
num_iters = tl.cdiv(K, STEP_K)
for k in range(num_iters):
# Current iteration's global K offset
iter_k = k * STEP_K + base_k
# Check if this iteration is completely valid (no masking needed)
block_end = iter_k + BLOCK_K
if EVEN_K:
# K is divisible by BLOCK_K, no masking ever needed
# pre-fetch lora weight
tiled_b = tl.load(b_ptr)
if USE_GDC:
tl.extra.cuda.gdc_wait()
tiled_a = tl.load(a_ptr)
if CAST_TYPE:
tiled_a = tiled_a.to(b_dtype)
accumulator += tl.dot(tiled_a, tiled_b)
else:
# Check if we need element-wise masking
if iter_k >= K:
# Entire block out of range, skip
pass
elif block_end <= K:
# Entire block in range, no masking needed (fast path)
tiled_b = tl.load(b_ptr)
if USE_GDC:
tl.extra.cuda.gdc_wait()
tiled_a = tl.load(a_ptr)
if CAST_TYPE:
tiled_a = tiled_a.to(b_dtype)
accumulator += tl.dot(tiled_a, tiled_b)
else:
# Partial block, need masking (only last iteration)
k_offsets = tl.arange(0, BLOCK_K)
mask = iter_k + k_offsets < K
tiled_b = tl.load(b_ptr, mask=mask[:, None], other=0.0)
if USE_GDC:
tl.extra.cuda.gdc_wait()
tiled_a = tl.load(a_ptr, mask=mask[None, :], other=0.0)
if CAST_TYPE:
tiled_a = tiled_a.to(b_dtype)
accumulator += tl.dot(tiled_a, tiled_b)
a_ptr += STEP_K * ak_stride
b_ptr += STEP_K * bk_stride
return accumulator
@triton.jit
def do_expand_kernel(
pid_n,
lora_index,
slice_id,
input_ptr,
lora_ptr,
out_ptr,
N,
K,
M_LEN,
ram, # array identifying the rows of Input ptr to operate on
slice_start_loc,
# input ptr strides
input_d0_stride,
input_d1_stride,
input_d2_stride,
# lora ptr strides
ls_d0_ptr,
ls_d1_ptr,
ls_d2_ptr,
# out ptr strides
output_d0_stride,
output_d1_stride,
# constants
BLOCK_M: tl.constexpr,
BLOCK_N: tl.constexpr,
BLOCK_K: tl.constexpr,
SAME_STRIDE: tl.constexpr,
SLICE_NUM: tl.constexpr,
EVEN_K: tl.constexpr,
CAST_TYPE: tl.constexpr,
ADD_INPUTS: tl.constexpr,
USE_GDC: tl.constexpr,
):
"""
Given an array of integers that identifies the rows of A, ram,
a lora index that identifies which LoRA to use from lora_ptr, lora_index,
a slice_id that identifies the input/output slice,
compute the matrix product and store in the appropriate output location.
Given that this is an expand kernel, we don't perform any split-K reduction
as the K dimension is assumed to be small.
"""
# ls_d*_ptr can be either an integer or a pointer
if SAME_STRIDE:
# integer
cur_lora_d0_stride = ls_d0_ptr
cur_lora_d1_stride = ls_d1_ptr
cur_lora_d2_stride = ls_d2_ptr
else:
# pointer
cur_lora_d0_stride = tl.load(ls_d0_ptr + slice_id)
cur_lora_d1_stride = tl.load(ls_d1_ptr + slice_id)
cur_lora_d2_stride = tl.load(ls_d2_ptr + slice_id)
# Identify the input_ptr and lora_ptr from slice_id.
if SLICE_NUM == 1:
cur_input_ptr = input_ptr
cur_lora_ptr = lora_ptr
else:
cur_input_ptr = input_ptr + slice_id * input_d0_stride
cur_lora_ptr = tl.load(lora_ptr + slice_id).to(
tl.pointer_type(out_ptr.dtype.element_ty)
)
# Identify the column indices of B to process.
offset_n = tl.arange(0, BLOCK_N) + pid_n * BLOCK_N
rbn = tl.max_contiguous(tl.multiple_of(offset_n % N, BLOCK_N), BLOCK_N)
# Identify A and B block pointers
offset_k = tl.arange(0, BLOCK_K)
a_ptr = (
cur_input_ptr
+ ram[:, None] * input_d1_stride
+ offset_k[None, :] * input_d2_stride
)
b_ptr = (
cur_lora_ptr
+ cur_lora_d0_stride * lora_index
+ offset_k[:, None] * cur_lora_d2_stride
+ rbn[None, :] * cur_lora_d1_stride
)
# Compute the block matrix product.
SPLIT_K = 1
accumulator = mm_k(
a_ptr,
b_ptr,
input_d2_stride,
cur_lora_d2_stride,
offset_k,
K,
BLOCK_M,
BLOCK_N,
BLOCK_K,
EVEN_K,
SPLIT_K,
CAST_TYPE,
cur_lora_ptr.dtype.element_ty,
USE_GDC,
base_k=0,
)
tiled_c = accumulator.to(cur_lora_ptr.dtype.element_ty)
if SLICE_NUM == 1:
cur_slice_start = slice_start_loc
else:
cur_slice_start = tl.load(slice_start_loc + slice_id)
# Identify the C output pointers to store the results of the accumulator.
offset_cn = tl.arange(0, BLOCK_N) + pid_n * BLOCK_N + cur_slice_start
offset_cm = tl.arange(0, BLOCK_M)
c_ptr = (
out_ptr
+ ram[:, None] * output_d0_stride
+ offset_cn[None, :] * output_d1_stride
)
c_mask = (offset_cm[:, None] < M_LEN) & (offset_cn[None, :] < (cur_slice_start + N))
if ADD_INPUTS:
tiled_out = tl.load(c_ptr, mask=c_mask)
tiled_c += tiled_out
tl.store(c_ptr, tiled_c, mask=c_mask)
@triton.jit
def do_shrink_kernel(
pid_n,
pid_sk,
slice_id,
lora_index,
input_ptr,
lora_ptr,
out_ptr,
N,
K,
M_LEN,
ram,
# input strides
input_d0_stride,
input_d1_stride,
# lora strides
lora_d0_stride,
lora_d1_stride,
lora_d2_stride,
# output strides
output_d0_stride,
output_d1_stride,
output_d2_stride,
scaling,
BLOCK_M: tl.constexpr,
BLOCK_N: tl.constexpr,
BLOCK_K: tl.constexpr,
EVEN_K: tl.constexpr,
SPLIT_K: tl.constexpr,
SLICE_NUM: tl.constexpr,
USE_GDC: tl.constexpr,
):
"""
Given an array of integers that identifies the rows of A, ram,
a lora index that identifies which LoRA to use from lora_ptr, lora_index,
a slice_id that identifies the input/output slice, compute the
matrix product and store in the appropriate output location.
"""
# Identify the lora_ptr from slice_id.
if SLICE_NUM == 1:
# current lora ptr
cur_lora_ptr = lora_ptr
else:
# current lora ptr
cur_lora_ptr = tl.load(lora_ptr + slice_id).to(
tl.pointer_type(input_ptr.dtype.element_ty)
)
# Identify the column indices of B to process.
offset_n = tl.arange(0, BLOCK_N) + pid_n * BLOCK_N
rbn = tl.max_contiguous(tl.multiple_of(offset_n % N, BLOCK_N), BLOCK_N)
# Identify A and B block pointers
offset_k = pid_sk * BLOCK_K + tl.arange(0, BLOCK_K)
a_ptr = (
input_ptr + ram[:, None] * input_d0_stride + offset_k[None, :] * input_d1_stride
)
b_ptr = (
cur_lora_ptr
+ lora_d0_stride * lora_index
+ rbn[None, :] * lora_d1_stride
+ offset_k[:, None] * lora_d2_stride
)
# Compute partial/complete block matrix product.
accumulator = mm_k(
a_ptr,
b_ptr,
input_d1_stride,
lora_d2_stride,
offset_k,
K,
BLOCK_M,
BLOCK_N,
BLOCK_K,
EVEN_K,
SPLIT_K,
False,
cur_lora_ptr.dtype.element_ty,
False, # USE_GDC is always False in shrink kernel
base_k=pid_sk * BLOCK_K,
)
# GDC launch dependents hints the runtime system to launch dependent kernels.
if USE_GDC:
tl.extra.cuda.gdc_launch_dependents()
# Identify the C output pointers to store the results of the accumulator.
offset_cn = tl.arange(0, BLOCK_N) + pid_n * BLOCK_N
offset_cm = tl.arange(0, BLOCK_M)
cur_out_ptr = out_ptr if SLICE_NUM == 1 else out_ptr + slice_id * output_d0_stride
c_ptr = (
cur_out_ptr
+ ram[:, None] * output_d1_stride
+ offset_cn[None, :] * output_d2_stride
)
c_mask = (offset_cm[:, None] < M_LEN) & (offset_cn[None, :] < N)
accumulator *= scaling
# handles write-back with reduction-splitting
if SPLIT_K == 1:
tl.store(c_ptr, accumulator, mask=c_mask)
else:
tl.atomic_add(c_ptr, accumulator, mask=c_mask, sem="relaxed")