vulkan: extend topk_moe to handle sigmoid w/exp_probs_b for nemotron (#18295)

* vulkan: extend topk_moe to handle sigmoid w/exp_probs_b for nemotron

Also handle GGML_OP_SCALE at the end (nemotron, deepseek2).

Fewer pipeline variants and spec constants, just use push constants.

In test_topk_moe, change exp_probs_b to be 1D, matching real networks.

Update test-backend-ops and ggml-backend to allow verifying multiple outputs
in a fusion test (topk_moe has two outputs). Previously only the final node
was verified.

* change test_topk_moe to allow results in arbitrary order

* disable sigmoid fusion for moltenvk
This commit is contained in:
Jeff Bolz
2026-01-01 08:58:27 +01:00
committed by GitHub
parent 9e10bd2eaf
commit be47fb9285
5 changed files with 234 additions and 69 deletions
@@ -7,6 +7,10 @@
#include "types.glsl"
#define GATING_FUNC_SOFTMAX 0
#define GATING_FUNC_SIGMOID 1
#define GATING_FUNC_SOFTMAX_WEIGHT 2
layout (push_constant) uniform parameter
{
uint n_rows;
@@ -14,15 +18,18 @@ layout (push_constant) uniform parameter
uint n_expert_used;
float clamp_min;
float clamp_max;
uint gating_func;
uint has_bias;
uint with_norm;
float output_scale;
float output_bias;
};
layout(local_size_x_id = 0, local_size_y = 4, local_size_z = 1) in;
layout(constant_id = 0) const uint WARP_SIZE = 32;
layout(constant_id = 1) const uint n_experts_spec = 512;
layout(constant_id = 2) const bool with_norm = true;
layout(constant_id = 3) const bool late_softmax = false;
layout(constant_id = 4) const bool nexperts_use_push = false;
layout(constant_id = 2) const bool nexperts_use_push = false;
uint n_experts = nexperts_use_push ? n_experts_push : n_experts_spec;
@@ -31,8 +38,9 @@ uint n_experts = nexperts_use_push ? n_experts_push : n_experts_spec;
const uint experts_per_thread = CEIL_DIV(n_experts_spec, WARP_SIZE);
layout (binding = 0, std430) readonly buffer Logits {float logits[];};
layout (binding = 1, std430) writeonly buffer Weights {float weights[];};
layout (binding = 2, std430) writeonly buffer Ids {uint ids[];};
layout (binding = 1, std430) readonly buffer BiasProbs {float bias[];};
layout (binding = 2, std430) writeonly buffer Weights {float weights[];};
layout (binding = 3, std430) writeonly buffer Ids {uint ids[];};
const float INFINITY = 1.0 / 0.0;
@@ -87,20 +95,40 @@ void main() {
}
const uint logits_offset = n_experts * row;
const uint bias_offset = 0; // 1D
const uint weights_offset = n_expert_used * row;
const uint ids_offset = n_experts * row;
const uint lane = gl_SubgroupInvocationID;
float wt[experts_per_thread];
float probs[experts_per_thread];
[[unroll]]
for (uint i = 0; i < n_experts; i += WARP_SIZE) {
const uint expert = i + lane;
wt[i / WARP_SIZE] = (n_experts % WARP_SIZE == 0 || expert < n_experts) ? logits[logits_offset + expert] : -INFINITY;
probs[i / WARP_SIZE] = (n_experts % WARP_SIZE == 0 || expert < n_experts) ? logits[logits_offset + expert] : -INFINITY;
}
if (!late_softmax) {
softmax_warp_inplace(wt, n_experts, lane, nexperts_use_push);
if (gating_func == GATING_FUNC_SOFTMAX) {
softmax_warp_inplace(probs, n_experts, lane, nexperts_use_push);
} else if (gating_func == GATING_FUNC_SIGMOID) {
[[unroll]]
for (int i = 0; i < experts_per_thread; i++) {
probs[i] = 1.f / (1.f + exp(-probs[i]));
}
}
float selection_probs[experts_per_thread];
if (has_bias != 0) {
[[unroll]]
for (uint i = 0; i < n_experts; i += WARP_SIZE) {
const uint expert = i + lane;
selection_probs[i / WARP_SIZE] = (n_experts % WARP_SIZE == 0 || expert < n_experts) ? probs[i / WARP_SIZE] + bias[bias_offset + expert] : -INFINITY;
}
} else {
[[unroll]]
for (int i = 0; i < experts_per_thread; i++) {
selection_probs[i] = probs[i];
}
}
// at this point, each thread holds a portion of softmax,
@@ -117,14 +145,16 @@ void main() {
}
for (int k = 0; k < n_expert_used; k++) {
float max_val = wt[0];
float max_val = probs[0];
float max_val_s = selection_probs[0];
uint max_expert = lane;
[[unroll]]
for (int i = 1; i < experts_per_thread; i++) {
const uint expert = lane + i * WARP_SIZE;
if ((n_experts % WARP_SIZE == 0 || expert < n_experts) && wt[i] > max_val) {
max_val = wt[i];
if ((n_experts % WARP_SIZE == 0 || expert < n_experts) && selection_probs[i] > max_val_s) {
max_val = probs[i];
max_val_s = selection_probs[i];
max_expert = expert;
}
}
@@ -132,9 +162,11 @@ void main() {
[[unroll]]
for (uint mask = WARP_SIZE / 2; mask > 0; mask /= 2) {
const float val = subgroupShuffleXor(max_val, mask);
const float val_s = subgroupShuffleXor(max_val_s, mask);
const uint expert = subgroupShuffleXor(max_expert, mask);
if (val > max_val || (val == max_val && expert < max_expert)) {
if (val_s > max_val_s || (val_s == max_val_s && expert < max_expert)) {
max_val = val;
max_val_s = val_s;
max_expert = expert;
}
}
@@ -144,16 +176,14 @@ void main() {
}
if ((max_expert & (WARP_SIZE - 1)) == lane) {
wt[max_expert / WARP_SIZE] = -INFINITY;
selection_probs[max_expert / WARP_SIZE] = -INFINITY;
ids[ids_offset + k] = max_expert;
if (with_norm) {
wt_sum += max_val;
}
wt_sum += max_val;
}
}
if (with_norm) {
if (with_norm != 0) {
wt_sum = subgroupAdd(wt_sum);
wt_sum = clamp(wt_sum, clamp_min, clamp_max);
const float inv_sum = 1.0f / wt_sum;
@@ -164,7 +194,7 @@ void main() {
}
}
if (late_softmax) {
if (gating_func == GATING_FUNC_SOFTMAX_WEIGHT) {
softmax_warp_inplace(output_weights, n_expert_used, lane, true);
}
@@ -172,7 +202,7 @@ void main() {
for (uint i = 0; i < experts_per_thread; ++i) {
uint idx = i * WARP_SIZE + lane;
if (idx < n_expert_used) {
weights[weights_offset + idx] = output_weights[i];
weights[weights_offset + idx] = output_scale * output_weights[i] + output_bias;
}
}
}