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metal: optimise GGML_OP_SUM #16559

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Merged
merged 4 commits into from
Oct 15, 2025
Merged

metal: optimise GGML_OP_SUM #16559

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9cc51d3
optimise GGML_OP_SUM
cern1710 Oct 13, 2025
4619142
add non-contiguous tests by permuting the input
cern1710 Oct 13, 2025
c25a6c7
change tests to require full contiguity of OP_SUM
cern1710 Oct 13, 2025
be1b670
cuda : add check GGML_OP_SUM
ggerganov Oct 15, 2025
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3 changes: 2 additions & 1 deletion ggml/src/ggml-cuda/ggml-cuda.cu
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Expand Up @@ -3645,9 +3645,10 @@ static bool ggml_backend_cuda_device_supports_op(ggml_backend_dev_t dev, const g
case GGML_OP_CONV_2D_DW:
case GGML_OP_CONV_TRANSPOSE_2D:
case GGML_OP_POOL_2D:
case GGML_OP_SUM:
case GGML_OP_ACC:
return true;
case GGML_OP_SUM:
return ggml_is_contiguous_rows(op->src[0]);
case GGML_OP_ARGSORT:
// TODO: Support arbitrary column width
return op->src[0]->ne[0] <= 1024;
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1 change: 1 addition & 0 deletions ggml/src/ggml-metal/ggml-metal-device.m
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Expand Up @@ -657,6 +657,7 @@ bool ggml_metal_device_supports_op(ggml_metal_device_t dev, const struct ggml_te
case GGML_OP_LOG:
return ggml_is_contiguous(op->src[0]) && op->src[0]->type == GGML_TYPE_F32;
case GGML_OP_SUM:
return has_simdgroup_reduction && ggml_is_contiguous(op->src[0]);
case GGML_OP_SUM_ROWS:
case GGML_OP_MEAN:
case GGML_OP_SOFT_MAX:
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15 changes: 14 additions & 1 deletion ggml/src/ggml-metal/ggml-metal-ops.cpp
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Expand Up @@ -866,12 +866,25 @@ int ggml_metal_op_sum(ggml_metal_op_t ctx, int idx) {

ggml_metal_pipeline_t pipeline = ggml_metal_library_get_pipeline_sum(lib, op);

int nth = 32; // SIMD width

while (nth < (int) n && nth < ggml_metal_pipeline_max_theads_per_threadgroup(pipeline)) {
nth *= 2;
}

nth = std::min(nth, ggml_metal_pipeline_max_theads_per_threadgroup(pipeline));
nth = std::min(nth, (int) n);

const int nsg = (nth + 31) / 32;

ggml_metal_encoder_set_pipeline(enc, pipeline);
ggml_metal_encoder_set_bytes (enc, &args, sizeof(args), 0);
ggml_metal_encoder_set_buffer (enc, ggml_metal_get_buffer_id(op->src[0]), 1);
ggml_metal_encoder_set_buffer (enc, ggml_metal_get_buffer_id(op), 2);

ggml_metal_encoder_dispatch_threadgroups(enc, 1, 1, 1, 1, 1, 1);
ggml_metal_encoder_set_threadgroup_memory_size(enc, nsg * sizeof(float), 0);

ggml_metal_encoder_dispatch_threadgroups(enc, 1, 1, 1, nth, 1, 1);

return 1;
}
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42 changes: 36 additions & 6 deletions ggml/src/ggml-metal/ggml-metal.metal
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Expand Up @@ -1727,18 +1727,48 @@ kernel void kernel_op_sum_f32(
constant ggml_metal_kargs_sum & args,
device const float * src0,
device float * dst,
ushort tiitg[[thread_index_in_threadgroup]]) {
threadgroup float * shmem_f32 [[threadgroup(0)]],
uint3 tgpig[[threadgroup_position_in_grid]],
ushort3 tpitg[[thread_position_in_threadgroup]],
ushort sgitg[[simdgroup_index_in_threadgroup]],
ushort tiisg[[thread_index_in_simdgroup]],
ushort3 ntg[[threads_per_threadgroup]]) {

if (tiitg != 0) {
if (args.np == 0) {
return;
}

float acc = 0.0f;
for (ulong i = 0; i < args.np; ++i) {
acc += src0[i];
const uint nsg = (ntg.x + 31) / 32;

float sumf = 0;

for (int64_t i0 = tpitg.x; i0 < args.np; i0 += ntg.x) {
sumf += src0[i0];
}

dst[0] = acc;
sumf = simd_sum(sumf);

if (tiisg == 0) {
shmem_f32[sgitg] = sumf;
}

threadgroup_barrier(mem_flags::mem_threadgroup);

float total = 0;

if (sgitg == 0) {
float v = 0;

if (tpitg.x < nsg) {
v = shmem_f32[tpitg.x];
}

total = simd_sum(v);

if (tpitg.x == 0) {
dst[0] = total;
}
}
}

template <bool norm>
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21 changes: 18 additions & 3 deletions tests/test-backend-ops.cpp
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Expand Up @@ -4588,20 +4588,31 @@ struct test_topk_moe: public test_case {
struct test_sum : public test_case {
const ggml_type type;
const std::array<int64_t, 4> ne;
const std::array<int64_t, 4> permute;
bool _use_permute;

std::string vars() override {
return VARS_TO_STR2(type, ne);
std::string v = VARS_TO_STR2(type, ne);
if (_use_permute) v += "," + VAR_TO_STR(permute);
return v;
}

test_sum(ggml_type type = GGML_TYPE_F32,
std::array<int64_t, 4> ne = {10, 5, 4, 3})
: type(type), ne(ne) {}
std::array<int64_t, 4> ne = {10, 5, 4, 3},
std::array<int64_t, 4> permute = {0, 0, 0, 0})
: type(type), ne(ne), permute(permute),
_use_permute(permute[0] + permute[1] + permute[2] + permute[3] > 0) {}

ggml_tensor * build_graph(ggml_context * ctx) override {
ggml_tensor * a = ggml_new_tensor(ctx, type, 4, ne.data());
ggml_set_param(a);
ggml_set_name(a, "a");

if (_use_permute) {
a = ggml_permute(ctx, a, permute[0], permute[1], permute[2], permute[3]);
ggml_set_name(a, "a_permuted");
}

ggml_tensor * out = ggml_sum(ctx, a);
ggml_set_name(out, "out");

Expand Down Expand Up @@ -6724,6 +6735,9 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {

test_cases.emplace_back(new test_sum());
test_cases.emplace_back(new test_sum_rows());
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, {11, 5, 6, 3}, {0, 2, 1, 3})); // row-contiguous but non-contiguous
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, {11, 5, 6, 3}, {0, 3, 2, 1}));
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, {11, 5, 6, 3}, {0, 1, 3, 2}));
test_cases.emplace_back(new test_sum_rows(GGML_TYPE_F32, { 11, 5, 6, 3 }, true, false));
test_cases.emplace_back(new test_sum_rows(GGML_TYPE_F32, { 11, 5, 6, 3 }, false, true));
test_cases.emplace_back(new test_sum_rows(GGML_TYPE_F32, { 11, 5, 6, 3 }, true, true));
Expand All @@ -6734,6 +6748,7 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, { 33, 1024, 1, 1 }));
test_cases.emplace_back(new test_sum_rows(GGML_TYPE_F32, { 33, 1024, 1, 1 }));
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, { 33, 256, 1, 1 }));
test_cases.emplace_back(new test_sum(GGML_TYPE_F32, { 33, 256, 1, 1 }, { 1, 0, 2, 3 })); // sum dst not-contiguous
test_cases.emplace_back(new test_sum_rows(GGML_TYPE_F32, { 33, 256, 1, 1 }));
test_cases.emplace_back(new test_mean(GGML_TYPE_F32, { 33, 256, 1, 1 }));
test_cases.emplace_back(new test_mean(GGML_TYPE_F32, { 32769, 1, 1, 1 }));
Expand Down