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[Metal][Performance]: Add split-K for quantized matmul (small M) #3120

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[Metal][Performance]: Add split-K for quantized matmul (small M) #3120

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67 changes: 61 additions & 6 deletions mlx/backend/metal/kernels/fp_quantized.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -642,6 +642,7 @@ METAL_FUNC void fp_qmm_t_impl(
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& K_eff,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
Expand Down Expand Up @@ -695,7 +696,7 @@ METAL_FUNC void fp_qmm_t_impl(

if (num_els < BM) {
if (!aligned_N && num_outs < BN) {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_safe(short2(BK, num_outs));
Expand All @@ -705,7 +706,7 @@ METAL_FUNC void fp_qmm_t_impl(
loader_w.next();
}
} else {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_unsafe();
Expand All @@ -717,7 +718,7 @@ METAL_FUNC void fp_qmm_t_impl(
}
} else {
if (!aligned_N && num_outs < BN) {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_safe(short2(BK, num_outs));
Expand All @@ -727,7 +728,7 @@ METAL_FUNC void fp_qmm_t_impl(
loader_w.next();
}
} else {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_unsafe();
Expand Down Expand Up @@ -1219,7 +1220,7 @@ template <
tid);
}
fp_qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
w, scales, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid);
w, scales, x, y, Xs, Ws, K, N, M, K, tid, lid, simd_gid, simd_lid);
}

template <
Expand Down Expand Up @@ -1486,7 +1487,61 @@ template <
s_strides,
tid);
fp_qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
w, scales, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid);
w, scales, x, y, Xs, Ws, K, N, M, K, tid, lid, simd_gid, simd_lid);
}

template <
typename T,
const int group_size,
const int bits,
const bool aligned_N,
const int BM = 32,
const int BK = 32,
const int BN = 32>
[[kernel]] void fp_qmm_t_splitk(
const device uint32_t* w [[buffer(0)]],
const device uint8_t* scales [[buffer(1)]],
const device T* x [[buffer(2)]],
device T* y [[buffer(3)]],
const constant int& K [[buffer(4)]],
const constant int& N [[buffer(5)]],
const constant int& M [[buffer(6)]],
const constant int& k_partition_size [[buffer(7)]],
const constant int& split_k_partition_stride [[buffer(8)]],
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 pack_factor = get_pack_factor<8, bits>();
constexpr int bytes_per_pack = get_bytes_per_pack();
threadgroup T Xs[BM * BK_padded];
threadgroup T Ws[BN * BK_padded];
const int k_start = tid.z * k_partition_size;
x += k_start;

auto wl = (const device uint8_t*)w;
wl += k_start * bytes_per_pack / pack_factor;
scales += k_start / group_size;
y += tid.z * static_cast<int64_t>(split_k_partition_stride);

fp_qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
(const device uint32_t*)wl,
scales,
x,
y,
Xs,
Ws,
K,
N,
M,
k_partition_size,
tid,
lid,
simd_gid,
simd_lid);
}

template <
Expand Down
4 changes: 3 additions & 1 deletion mlx/backend/metal/kernels/fp_quantized.metal
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,9 @@

#define instantiate_quantized_all_splitk(type, mode, group_size, bits) \
instantiate_quantized_split_k(mode, qvm_split_k, type, 8, group_size, bits) \
instantiate_quantized_split_k(mode, qvm_split_k, type, 32, group_size, bits)
instantiate_quantized_split_k(mode, qvm_split_k, type, 32, group_size, bits) \
instantiate_quantized_aligned(mode, qmm_t_splitk, type, true, group_size, bits) \
instantiate_quantized_aligned(mode, qmm_t_splitk, type, false, group_size, bits)

#define instantiate_quantized_all_rhs(type, mode, group_size, bits) \
instantiate_gather_qmm_rhs(fp_gather_qmm_rhs, gather_qmm_rhs_nt, type, 16, 32, 32, 1, 2, true, mode, group_size, bits) \
Expand Down
100 changes: 94 additions & 6 deletions mlx/backend/metal/kernels/quantized.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1102,6 +1102,7 @@ METAL_FUNC void qmm_t_impl(
const constant int& K,
const constant int& N,
const constant int& M,
const constant int& K_eff,
uint3 tid [[threadgroup_position_in_grid]],
uint lid [[thread_index_in_threadgroup]],
uint simd_gid [[simdgroup_index_in_threadgroup]],
Expand Down Expand Up @@ -1156,7 +1157,7 @@ METAL_FUNC void qmm_t_impl(

if (num_els < BM) {
if (!aligned_N && num_outs < BN) {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_safe(short2(BK, num_outs));
Expand All @@ -1166,7 +1167,7 @@ METAL_FUNC void qmm_t_impl(
loader_w.next();
}
} else {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_safe(short2(BK, num_els));
loader_w.load_unsafe();
Expand All @@ -1178,7 +1179,7 @@ METAL_FUNC void qmm_t_impl(
}
} else {
if (!aligned_N && num_outs < BN) {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_safe(short2(BK, num_outs));
Expand All @@ -1188,7 +1189,7 @@ METAL_FUNC void qmm_t_impl(
loader_w.next();
}
} else {
for (int k = 0; k < K; k += BK) {
for (int k = 0; k < K_eff; k += BK) {
threadgroup_barrier(mem_flags::mem_threadgroup);
loader_x.load_unsafe();
loader_w.load_unsafe();
Expand Down Expand Up @@ -1759,7 +1760,80 @@ template <
tid);
}
qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
w, scales, biases, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid);
w,
scales,
biases,
x,
y,
Xs,
Ws,
K,
N,
M,
K,
tid,
lid,
simd_gid,
simd_lid);
}

template <
typename T,
const int group_size,
const int bits,
const bool aligned_N,
const int BM = 32,
const int BK = 32,
const int BN = 32>
[[kernel]] void affine_qmm_t_splitk(
const device uint32_t* w [[buffer(0)]],
const device T* scales [[buffer(1)]],
const device T* biases [[buffer(2)]],
const device T* x [[buffer(3)]],
device T* y [[buffer(4)]],
const constant int& K [[buffer(5)]],
const constant int& N [[buffer(6)]],
const constant int& M [[buffer(7)]],
const constant int& k_partition_size [[buffer(8)]],
const constant int& split_k_partition_stride [[buffer(9)]],
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 pack_factor = get_pack_factor<bits, 8>();
constexpr int bytes_per_pack = get_bytes_per_pack<bits>();

threadgroup T Xs[BM * BK_padded];
threadgroup T Ws[BN * BK_padded];

const int k_start = tid.z * k_partition_size;
x += k_start;

auto wl = (const device uint8_t*)w;
wl += k_start * bytes_per_pack / pack_factor;
scales += k_start / group_size;
biases += k_start / group_size;
y += tid.z * static_cast<int64_t>(split_k_partition_stride);

qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
(const device uint32_t*)wl,
scales,
biases,
x,
y,
Xs,
Ws,
K,
N,
M,
k_partition_size,
tid,
lid,
simd_gid,
simd_lid);
}

template <
Expand Down Expand Up @@ -2073,7 +2147,21 @@ template <
b_strides,
tid);
qmm_t_impl<T, group_size, bits, aligned_N, BM, BK, BN>(
w, scales, biases, x, y, Xs, Ws, K, N, M, tid, lid, simd_gid, simd_lid);
w,
scales,
biases,
x,
y,
Xs,
Ws,
K,
N,
M,
K,
tid,
lid,
simd_gid,
simd_lid);
}

template <
Expand Down
16 changes: 15 additions & 1 deletion mlx/backend/metal/kernels/quantized.metal
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -109,7 +109,20 @@

#define instantiate_quantized_all_splitk(type, group_size, bits) \
instantiate_quantized_split_k(affine_qvm_split_k, type, group_size, bits, 8) \
instantiate_quantized_split_k(affine_qvm_split_k, type, group_size, bits, 32)
instantiate_quantized_split_k(affine_qvm_split_k, type, group_size, bits, 32) \

#define instantiate_quantized_splitk_qmm(name, type, group_size, bits, aligned) \
instantiate_kernel( \
#name "_" #type "_gs_" #group_size "_b_" #bits "_alN_" #aligned, \
name, \
type, \
group_size, \
bits, \
aligned)

#define instantiate_quantized_all_splitk_qmm(type, group_size, bits) \
instantiate_quantized_splitk_qmm(affine_qmm_t_splitk, type, group_size, bits, true) \
instantiate_quantized_splitk_qmm(affine_qmm_t_splitk, type, group_size, bits, false)

#define instantiate_quantized_all_rhs(type, group_size, bits) \
instantiate_gather_qmm_rhs(affine_gather_qmm_rhs, affine_gather_qmm_rhs_nt, type, group_size, bits, 16, 32, 32, 1, 2, true) \
Expand All @@ -121,6 +134,7 @@
instantiate_quantized_all_aligned(type, group_size, bits) \
instantiate_quantized_all_quad(type, group_size, bits) \
instantiate_quantized_all_splitk(type, group_size, bits) \
instantiate_quantized_all_splitk_qmm(type, group_size, bits) \
instantiate_quantized_all_rhs(type, group_size, bits)

#define instantiate_quantized_types(group_size, bits) \
Expand Down
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