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mlx/mlx/backend/metal/kernels/fp_quantized_nax.h
2025-11-19 15:06:00 -08:00

1067 lines
29 KiB
C++

// Copyright © 2025 Apple Inc.
#include <metal_simdgroup>
#include <metal_stdlib>
#include "mlx/backend/metal/kernels/fp4.h"
#include "mlx/backend/metal/kernels/fp8.h"
constant bool align_M [[function_constant(200)]];
constant bool align_N [[function_constant(201)]];
constant bool align_K [[function_constant(202)]];
using namespace metal;
#define MLX_MTL_CONST static constant constexpr const
MLX_MTL_CONST int SIMD_SIZE = 32;
MLX_MTL_CONST int QUAD_SIZE = 4;
template <int wsize = 8>
inline constexpr short get_pack_factor() {
return wsize / 4;
}
template <int wsize = 8>
inline constexpr short get_bytes_per_pack() {
return wsize / 8;
}
template <typename T>
static inline T dequantize_scale(uint8_t s) {
return T(*(thread fp8_e8m0*)(&s));
}
template <int bits>
struct Quantize {
uint8_t operator()(float x) {
if constexpr (bits == 8) {
return fp8_e4m3(x).bits;
} else {
return fp4_e2m1(x).bits;
}
}
};
template <int bits>
struct Dequantize {
float operator()(uint8_t x) {
if constexpr (bits == 8) {
return float(*(thread fp8_e4m3*)(&x));
} else {
return float(*(thread fp4_e2m1*)(&x));
}
}
};
template <typename U, int N>
inline void dequantize(
const device uint8_t* w,
U scale,
threadgroup U* w_local,
const threadgroup U* lut) {
for (int i = 0; i < (N / 2); i++) {
w_local[2 * i] = scale * lut[w[i] & 0xf];
w_local[2 * i + 1] = scale * lut[(w[i] >> 4) & 0xf];
}
}
template <
typename T,
short BROWS,
short BCOLS,
short dst_ld,
short reduction_dim,
short tgp_size,
short group_size>
struct QuantizedBlockLoader {
static_assert(
BCOLS % group_size == 0,
"The group size should be divisible by the columns");
MLX_MTL_CONST short pack_factor = get_pack_factor<8>();
MLX_MTL_CONST short bytes_per_pack = get_bytes_per_pack();
MLX_MTL_CONST short BCOLS_PACKED = BCOLS / pack_factor;
MLX_MTL_CONST short n_reads =
(BCOLS_PACKED * BROWS < tgp_size) ? 1 : (BCOLS_PACKED * BROWS) / tgp_size;
MLX_MTL_CONST short n_groups = BCOLS / group_size;
static_assert(
(BCOLS_PACKED / n_reads) == n_groups,
"Other configurations are not yet supported");
const int src_ld;
const int tile_stride;
const int group_stride;
const short thread_idx;
const short bi;
const short bj;
const short group_id;
threadgroup T* dst;
const device uint8_t* src;
const device uint8_t* scales;
threadgroup T* lut;
QuantizedBlockLoader(
const device uint8_t* src_,
const device uint8_t* scales_,
const int src_ld_,
threadgroup T* dst_,
threadgroup T* lut_,
ushort simd_group_id [[simdgroup_index_in_threadgroup]],
ushort simd_lane_id [[thread_index_in_simdgroup]])
: src_ld(src_ld_),
tile_stride(
reduction_dim ? BCOLS_PACKED * bytes_per_pack
: BROWS * src_ld * bytes_per_pack / pack_factor),
group_stride(BROWS * src_ld / group_size),
thread_idx(simd_group_id * 32 + simd_lane_id),
bi(n_reads * thread_idx / BCOLS_PACKED),
bj((n_reads * thread_idx) % BCOLS_PACKED),
group_id((bj * pack_factor) / group_size),
dst(dst_ + bi * dst_ld + bj * pack_factor),
src(src_ + bi * src_ld * bytes_per_pack / pack_factor +
bj * bytes_per_pack),
scales(scales_ + bi * src_ld / group_size + group_id),
lut(lut_) {
if (simd_group_id == 0 && simd_lane_id < 16) {
lut[simd_lane_id] = static_cast<T>(FP4_LUT[simd_lane_id]);
}
threadgroup_barrier(mem_flags::mem_threadgroup);
}
void load_unsafe() const {
if (BCOLS_PACKED * BROWS < tgp_size && bi >= BROWS) {
return;
}
T scale = dequantize_scale<T>(*scales);
for (int i = 0; i < n_reads; i++) {
dequantize<T, pack_factor>(
src + i * bytes_per_pack, scale, dst + i * pack_factor, lut);
}
}
void load_safe(short2 src_tile_dim) const {
if (BCOLS_PACKED * BROWS < tgp_size && bi >= BROWS) {
return;
}
if (reduction_dim == 1 && bi >= src_tile_dim.x) {
for (int i = 0; i < n_reads * pack_factor; i++) {
dst[i] = T(0);
}
return;
}
if (reduction_dim == 0 && bi >= src_tile_dim.y) {
for (int i = 0; i < n_reads * pack_factor; i++) {
dst[i] = T(0);
}
return;
}
T scale = dequantize_scale<T>(*scales);
for (int i = 0; i < n_reads; i++) {
dequantize<T, pack_factor>(
(device uint8_t*)(src + i * bytes_per_pack),
scale,
dst + i * pack_factor,
lut);
}
}
void next() {
src += tile_stride;
if (reduction_dim == 1) {
// if (group_steps > 1) {
// group_step_cnt++;
// if (group_step_cnt == group_steps) {
// group_step_cnt = 0;
// scales++;
// }
// } else {
scales += n_groups;
// }
} else {
scales += n_groups * group_stride;
}
}
};
using namespace mlx::steel;
template <
typename T,
const int group_size,
const int bits,
const bool aligned_N,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
METAL_FUNC void fp_qmm_t_impl(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
device T* y,
threadgroup Wtype* Ws,
const constant int& K,
const constant int& N,
const constant int& M,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]],
threadgroup Wtype* lut) {
static_assert(BK >= SIMD_SIZE, "BK should be larger than SIMD_SIZE");
static_assert(BK % SIMD_SIZE == 0, "BK should be divisible by SIMD_SIZE");
(void)lid;
constexpr int pack_factor = get_pack_factor<8>();
constexpr int bytes_per_pack = get_bytes_per_pack();
constexpr int BK_padded = (BK + 16 / sizeof(Wtype));
// Instantiate Loader
using loader_w_t = QuantizedBlockLoader<
Wtype,
BN,
BK,
BK_padded,
1,
WM * WN * SIMD_SIZE,
group_size>;
// Set the block
const int K_w = K * bytes_per_pack / pack_factor;
const int K_g = K / group_size;
const int y_row = tid.y * BM;
const int y_col = tid.x * BN;
auto wl = (const device uint8_t*)w;
x += y_row * static_cast<int64_t>(K);
wl += y_col * K_w;
scales += y_col * K_g;
y += y_row * static_cast<int64_t>(N) + y_col;
// Make the weight loader
loader_w_t loader_w(wl, scales, K, Ws, lut, simd_gid, simd_lid);
constexpr short UM = 16;
constexpr short UN = 32;
constexpr short UK = 16;
constexpr short SM = BM / WM;
constexpr short SN = BN / WN;
constexpr short SK = 32;
constexpr short TM = SM / UM;
constexpr short TN = SN / UN;
constexpr short TK = SK / UK;
const short tm = SM * (simd_gid / WN);
const short tn = SN * (simd_gid % WN);
constexpr bool transpose_a = false;
constexpr bool transpose_b = true;
const short sgp_sm = min(SM, short(M - (y_row + tm)));
const bool is_unaligned_sm = (sgp_sm != SM);
const short sgp_sn = aligned_N ? SN : min(SN, short(N - (y_col + tn)));
const short tgp_bn = aligned_N ? BN : min(BN, int(N - (y_col)));
const bool is_unaligned_bn = aligned_N ? false : (tgp_bn != BN);
using AccumType = float;
using ASubTile = NAXSubTile<T, UM, UK>;
using BSubTile = NAXSubTile<Wtype, UN, UK>;
using DSubTile = NAXSubTile<AccumType, UM, UN>;
NAXTile<AccumType, TM, TN, DSubTile> Dtile;
Dtile.clear();
x += tm * K;
dispatch_bool(!is_unaligned_sm, [&](auto kAlignedM) {
dispatch_bool(aligned_N || !is_unaligned_bn, [&](auto kAlignedN) {
for (int k = 0; k < K; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
if constexpr (kAlignedN.value) {
loader_w.load_unsafe();
} else {
loader_w.load_safe(short2(BK, tgp_bn));
}
threadgroup_barrier(mem_flags::mem_threadgroup);
STEEL_PRAGMA_NO_UNROLL
for (int kk1 = 0; kk1 < BK; kk1 += SK) {
NAXTile<T, TM, TK, ASubTile> Atile;
NAXTile<Wtype, TN, TK, BSubTile> Btile;
volatile int compiler_barrier;
if constexpr (kAlignedM.value) {
Atile.load(x + kk1, K);
} else {
Atile.load_safe(x + kk1, K, short2(SK, sgp_sm));
}
Btile.template load<Wtype, BK_padded, 1>(Ws + tn * BK_padded + kk1);
tile_matmad_nax(
Dtile,
Atile,
metal::bool_constant<transpose_a>{},
Btile,
metal::bool_constant<transpose_b>{});
(void)compiler_barrier;
}
x += BK;
loader_w.next();
}
// Store results to device memory
threadgroup_barrier(mem_flags::mem_threadgroup);
if constexpr (kAlignedM.value && kAlignedN.value) {
Dtile.store(y + tm * N + tn, N);
} else if (kAlignedM.value && sgp_sn == SN) {
Dtile.store(y + tm * N + tn, N);
} else {
Dtile.store_safe(y + tm * N + tn, N, short2(sgp_sn, sgp_sm));
}
});
});
}
template <
typename T,
const int group_size,
const int bits,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
METAL_FUNC void fp_qmm_n_impl(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
device T* y,
threadgroup T* Xs,
threadgroup T* Ws,
const constant int& K,
const constant int& N,
const constant int& M,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]],
threadgroup T* lut) {
static_assert(BK >= SIMD_SIZE, "BK should be larger than SIMD_SIZE");
static_assert(BK % SIMD_SIZE == 0, "BK should be divisible by SIMD_SIZE");
(void)lid;
constexpr int pack_factor = get_pack_factor<8>();
constexpr int bytes_per_pack = get_bytes_per_pack();
constexpr int BK_padded = (BK + 16 / sizeof(T));
constexpr int BN_padded = (BN + 16 / sizeof(T));
// Instantiate the appropriate BlockMMA and Loader
using mma_t = mlx::steel::
BlockMMA<T, T, BM, BN, BK, WM, WN, false, false, BK_padded, BN_padded>;
using loader_x_t = mlx::steel::
BlockLoader<T, BM, BK, BK_padded, 1, WM * WN * SIMD_SIZE, 1, 4>;
using loader_w_t = QuantizedBlockLoader<
T,
BK,
BN,
BN_padded,
0,
WM * WN * SIMD_SIZE,
group_size>;
auto wl = (const device uint8_t*)w;
// Set the block
const int y_row = tid.y * BM;
const int y_col = tid.x * BN;
x += y_row * static_cast<int64_t>(K);
wl += y_col * bytes_per_pack / pack_factor;
scales += y_col / group_size;
y += y_row * static_cast<int64_t>(N) + y_col;
// Make the x loader and mma operation
const short num_els = min(BM, M - y_row);
loader_x_t loader_x(x, K, Xs, simd_gid, simd_lid);
loader_w_t loader_w(wl, scales, N, Ws, lut, simd_gid, simd_lid);
mma_t mma_op(simd_gid, simd_lid);
if (num_els < BM) {
if ((K % BK) != 0) {
const int k_blocks = K / BK;
for (int k = 0; k < k_blocks; k++) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_unsafe();
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
loader_x.next();
loader_w.next();
}
const short num_k = K - k_blocks * BK;
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(num_k, num_els));
loader_w.load_safe(short2(BN, num_k));
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
} else {
for (int k = 0; k < K; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_unsafe();
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
loader_x.next();
loader_w.next();
}
}
} else {
if ((K % BK) != 0) {
const int k_blocks = K / BK;
for (int k = 0; k < k_blocks; k++) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_unsafe();
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
loader_x.next();
loader_w.next();
}
const short num_k = K - k_blocks * BK;
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(num_k, BM));
loader_w.load_safe(short2(BN, num_k));
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
} else {
for (int k = 0; k < K; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_unsafe();
threadgroup_barrier(mem_flags::mem_threadgroup);
mma_op.mma(Xs, Ws);
loader_x.next();
loader_w.next();
}
}
}
// Store results to device memory
threadgroup_barrier(mem_flags::mem_threadgroup);
if (num_els < BM) {
mma_op.store_result_safe(y, N, short2(BN, num_els));
} else {
mma_op.store_result(y, N);
}
}
template <typename T, typename S>
METAL_FUNC void adjust_matrix_offsets(
const device T*& x,
const device uint32_t*& w,
const device S*& scales,
device T*& y,
int output_stride,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
uint3 tid [[threadgroup_position_in_grid]]) {
// Set the input/output matrices
uint32_t x_idx = tid.z;
uint32_t w_idx = tid.z;
if (x_batch_ndims == 1) {
x += x_idx * x_strides[0];
} else {
x += elem_to_loc(x_idx, x_shape, x_strides, x_batch_ndims);
}
if (w_batch_ndims == 1) {
w += w_idx * w_strides[0];
scales += w_idx * s_strides[0];
} else {
ulong2 idx = elem_to_loc_broadcast(
w_idx, w_shape, w_strides, s_strides, w_batch_ndims);
w += idx.x;
scales += idx.y;
}
y += tid.z * output_stride;
}
template <typename T, typename S>
METAL_FUNC void adjust_matrix_offsets(
const device T*& x,
const device uint32_t*& w,
const device S*& scales,
const device uint32_t* lhs_indices,
const device uint32_t* rhs_indices,
device T*& y,
int output_stride,
const constant int& batch_ndims,
const constant int* batch_shape,
const constant int64_t* lhs_strides,
const constant int64_t* rhs_strides,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
uint3 tid [[threadgroup_position_in_grid]]) {
// Set the input/output matrices
uint32_t x_idx;
uint32_t w_idx;
if (batch_ndims == 1) {
x_idx = lhs_indices[tid.z * lhs_strides[0]];
w_idx = rhs_indices[tid.z * rhs_strides[0]];
} else {
ulong2 idx = elem_to_loc_broadcast(
tid.z, batch_shape, lhs_strides, rhs_strides, batch_ndims);
x_idx = lhs_indices[idx.x];
w_idx = rhs_indices[idx.y];
}
if (x_batch_ndims == 1) {
x += x_idx * x_strides[0];
} else {
x += elem_to_loc(x_idx, x_shape, x_strides, x_batch_ndims);
}
if (w_batch_ndims == 1) {
w += w_idx * w_strides[0];
scales += w_idx * s_strides[0];
} else {
ulong2 idx = elem_to_loc_broadcast(
w_idx, w_shape, w_strides, s_strides, w_batch_ndims);
w += idx.x;
scales += idx.y;
}
y += tid.z * output_stride;
}
template <
typename T,
const int group_size,
const int bits,
const bool aligned_N,
const bool batched,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
[[kernel]] void fp_qmm_t_nax(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
device T* y,
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]]) {
(void)lid;
constexpr int BK_padded = (BK + 16 / sizeof(Wtype));
threadgroup Wtype Ws[BN * BK_padded];
threadgroup Wtype lut[16];
if (batched) {
adjust_matrix_offsets(
x,
w,
scales,
y,
M * N,
x_batch_ndims,
x_shape,
x_strides,
w_batch_ndims,
w_shape,
w_strides,
s_strides,
tid);
}
fp_qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN, WM, WN, Wtype>(
w, scales, x, y, Ws, K, N, M, tid, lid, simd_gid, simd_lid, lut);
}
template <
typename T,
const int group_size,
const int bits,
const bool batched,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
[[kernel]] void fp_qmm_n_nax(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
device T* y,
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]]) {
(void)lid;
constexpr int BK_padded = (BK + 16 / sizeof(T));
constexpr int BN_padded = (BN + 16 / sizeof(T));
threadgroup T Xs[BM * BK_padded];
threadgroup T Ws[BK * BN_padded];
threadgroup T lut[16];
if (batched) {
adjust_matrix_offsets(
x,
w,
scales,
y,
M * N,
x_batch_ndims,
x_shape,
x_strides,
w_batch_ndims,
w_shape,
w_strides,
s_strides,
tid);
}
fp_qmm_n_impl<T, group_size, bits, BM, BK, BN, WM, WN, Wtype>(
w, scales, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid, lut);
}
template <
typename T,
const int group_size,
const int bits,
const bool aligned_N,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
[[kernel]] void fp_gather_qmm_t_nax(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
const device uint32_t* lhs_indices,
const device uint32_t* rhs_indices,
device T* y,
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
const constant int& batch_ndims,
const constant int* batch_shape,
const constant int64_t* lhs_strides,
const constant int64_t* rhs_strides,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]]) {
(void)lid;
constexpr int BK_padded = (BK + 16 / sizeof(Wtype));
threadgroup Wtype Ws[BN * BK_padded];
threadgroup Wtype lut[16];
adjust_matrix_offsets(
x,
w,
scales,
lhs_indices,
rhs_indices,
y,
M * N,
batch_ndims,
batch_shape,
lhs_strides,
rhs_strides,
x_batch_ndims,
x_shape,
x_strides,
w_batch_ndims,
w_shape,
w_strides,
s_strides,
tid);
fp_qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN, WM, WN, Wtype>(
w, scales, x, y, Ws, K, N, M, tid, lid, simd_gid, simd_lid, lut);
}
template <
typename T,
const int group_size,
const int bits,
const int BM = 64,
const int BK = 64,
const int BN = 64,
const int WM = 2,
const int WN = 2,
typename Wtype = bfloat>
[[kernel]] void fp_gather_qmm_n_nax(
const device uint32_t* w,
const device uint8_t* scales,
const device T* x,
const device uint32_t* lhs_indices,
const device uint32_t* rhs_indices,
device T* y,
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& x_batch_ndims,
const constant int* x_shape,
const constant int64_t* x_strides,
const constant int& w_batch_ndims,
const constant int* w_shape,
const constant int64_t* w_strides,
const constant int64_t* s_strides,
const constant int& batch_ndims,
const constant int* batch_shape,
const constant int64_t* lhs_strides,
const constant int64_t* rhs_strides,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
uint simd_lid [[thread_index_in_simdgroup]]) {
(void)lid;
constexpr int BK_padded = (BK + 16 / sizeof(T));
constexpr int BN_padded = (BN + 16 / sizeof(T));
threadgroup T Xs[BM * BK_padded];
threadgroup T Ws[BK * BN_padded];
threadgroup T lut[16];
adjust_matrix_offsets(
x,
w,
scales,
lhs_indices,
rhs_indices,
y,
M * N,
batch_ndims,
batch_shape,
lhs_strides,
rhs_strides,
x_batch_ndims,
x_shape,
x_strides,
w_batch_ndims,
w_shape,
w_strides,
s_strides,
tid);
fp_qmm_n_impl<T, group_size, bits, BM, BK, BN, WM, WN, Wtype>(
w, scales, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid, lut);
}
template <
typename T,
int group_size,
const int bits,
int BM,
int BN,
int BK,
int WM,
int WN,
bool transpose,
typename Wtype = bfloat>
[[kernel]] void fp_gather_qmm_rhs_nax(
const device T* x,
const device uint32_t* w,
const device uint8_t* scales,
const device uint32_t* indices,
device T* y,
const constant int& M,
const constant int& N,
const constant int& K,
uint3 tid [[threadgroup_position_in_grid]],
uint simd_group_id [[simdgroup_index_in_threadgroup]],
uint simd_lane_id [[thread_index_in_simdgroup]]) {
constexpr int pack_factor = get_pack_factor<8>();
constexpr int bytes_per_pack = get_bytes_per_pack();
constexpr int BK_padded = (BK + 16 / sizeof(Wtype));
constexpr int BN_padded = (BN + 16 / sizeof(Wtype));
threadgroup Wtype lut[16];
using loader_w_t = QuantizedBlockLoader<
Wtype,
transpose ? BN : BK,
transpose ? BK : BN,
transpose ? BK_padded : BN_padded,
transpose,
WM * WN * SIMD_SIZE,
group_size>;
threadgroup Wtype Ws[transpose ? BN * BK_padded : BK * BN_padded];
// Compute the block
const int K_w = K * bytes_per_pack / pack_factor;
const int K_g = K / group_size;
const int N_w = N * bytes_per_pack / pack_factor;
const int N_g = N / group_size;
const int K_it = K / BK;
const size_t stride_w = transpose ? N * K_w : K * N_w;
const size_t stride_s = transpose ? N * K_g : K * N_g;
const int y_row = tid.y * BM;
const int y_col = tid.x * BN;
const size_t y_row_long = size_t(y_row);
const size_t y_col_long = size_t(y_col);
// Prepare threadgroup bounds
const short tgp_bm = align_M ? BM : short(min(BM, M - y_row));
const short tgp_bn = align_N ? BN : short(min(BN, N - y_col));
// Calculate the final tiles in the case that K is not aligned
const int k_remain = K - K_it * BK;
const short2 tile_w =
transpose ? short2(k_remain, tgp_bn) : short2(tgp_bn, k_remain);
// Move x and output to the correct block
auto wl = (const device uint8_t*)w;
x += y_row_long * K;
y += y_row_long * N + y_col_long;
wl += transpose ? y_col_long * K_w : y_col * bytes_per_pack / pack_factor;
scales += transpose ? y_col_long * K_g : y_col / group_size;
constexpr short UM = 16;
constexpr short UN = 32;
constexpr short UK = 16;
constexpr short SM = BM / WM;
constexpr short SN = BN / WN;
constexpr short SK = 32;
constexpr short TM = SM / UM;
constexpr short TN = SN / UN;
constexpr short TK = SK / UK;
const short tm = SM * (simd_group_id / WN);
const short tn = SN * (simd_group_id % WN);
const short sgp_sm =
align_M ? SM : min(SM, short(max(0, (M - (y_row + tm)))));
const short sgp_sn =
align_N ? SN : min(SN, short(max(0, (N - (y_col + tn)))));
const bool is_unaligned_sm = align_M ? false : (sgp_sm != SM);
const bool is_unaligned_bn = align_N ? false : (tgp_bn != BN);
constexpr short BR = transpose ? TN : TK;
constexpr short BC = transpose ? TK : TN;
using AccumType = float;
using ASubTile = NAXSubTile<T, UM, UK>;
using BSubTile = NAXSubTile<Wtype, transpose ? UN : UK, transpose ? UK : UN>;
using DSubTile = NAXSubTile<AccumType, UM, UN>;
// Do as many matmuls as necessary
uint32_t index;
short offset;
uint32_t index_next = indices[y_row];
short offset_next = 0;
int n = 0;
while (n < tgp_bm) {
n++;
offset = offset_next;
index = index_next;
offset_next = tgp_bm;
for (; n < tgp_bm; n++) {
if (indices[y_row + n] != index) {
offset_next = n;
index_next = indices[y_row + n];
break;
}
}
threadgroup_barrier(mem_flags::mem_none);
// Prepare threadgroup mma operation
NAXTile<AccumType, TM, TN, DSubTile> Dtile;
Dtile.clear();
const device T* xn = x + tm * K;
// Prepare threadgroup loading operations
thread loader_w_t loader_w(
wl + index * stride_w,
scales + index * stride_s,
transpose ? K : N,
Ws,
lut,
simd_group_id,
simd_lane_id);
dispatch_bool(align_M || !is_unaligned_sm, [&](auto kAlignedM) {
dispatch_bool(align_N || !is_unaligned_bn, [&](auto kAlignedN) {
for (int k = 0; k < K_it; k++) {
threadgroup_barrier(mem_flags::mem_threadgroup);
if constexpr (kAlignedN.value) {
loader_w.load_unsafe();
} else {
loader_w.load_safe(
transpose ? short2(BK, tgp_bn) : short2(tgp_bn, BK));
}
threadgroup_barrier(mem_flags::mem_threadgroup);
STEEL_PRAGMA_NO_UNROLL
for (int kk1 = 0; kk1 < BK; kk1 += SK) {
NAXTile<T, TM, TK, ASubTile> Atile;
NAXTile<Wtype, BR, BC, BSubTile> Btile;
volatile int compiler_barrier;
if constexpr (kAlignedM.value) {
Atile.load(xn + kk1, K);
} else {
Atile.load_safe(xn + kk1, K, short2(SK, sgp_sm));
}
if constexpr (transpose) {
Btile.template load<Wtype, BK_padded, 1>(
Ws + tn * BK_padded + kk1);
} else {
Btile.template load<Wtype, BN_padded, 1>(
Ws + tn + kk1 * BN_padded);
}
tile_matmad_nax(
Dtile,
Atile,
metal::bool_constant<false>{},
Btile,
metal::bool_constant<transpose>{});
(void)compiler_barrier;
}
xn += BK;
loader_w.next();
}
if (!align_K) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_w.load_safe(tile_w);
threadgroup_barrier(mem_flags::mem_threadgroup);
STEEL_PRAGMA_NO_UNROLL
for (int kk1 = 0; kk1 < BK; kk1 += SK) {
NAXTile<T, TM, TK, ASubTile> Atile;
NAXTile<Wtype, BR, BC, BSubTile> Btile;
volatile int compiler_barrier;
const short psk = min(int(SK), max(0, (BK - kk1)));
Atile.load_safe(xn + kk1, K, short2(psk, sgp_sm));
if constexpr (transpose) {
Btile.template load<Wtype, BK_padded, 1>(
Ws + tn * BK_padded + kk1);
} else {
Btile.template load<Wtype, BN_padded, 1>(
Ws + tn + kk1 * BN_padded);
}
tile_matmad_nax(
Dtile,
Atile,
metal::bool_constant<false>{},
Btile,
metal::bool_constant<transpose>{});
(void)compiler_barrier;
}
}
threadgroup_barrier(mem_flags::mem_threadgroup);
const short m_lo_lim = min(int(sgp_sm), max(0, offset - tm));
const short m_hi_lim = min(int(sgp_sm), max(0, offset_next - tm));
// Store results to device memory
if constexpr (kAlignedN.value) {
if (m_lo_lim == 0 && m_hi_lim == SM) {
Dtile.store(y + tm * N + tn, N);
} else {
Dtile.store_slice(
y + tm * N + tn, N, short2(0, m_lo_lim), short2(SN, m_hi_lim));
}
} else {
Dtile.store_slice(
y + tm * N + tn,
N,
short2(0, m_lo_lim),
short2(sgp_sn, m_hi_lim));
}
});
});
}
}