Skip to content

Vulkan: some improvement on mul_mat_iq2_xs #18031

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
0cc4m merged 3 commits into from
Dec 21, 2025
Merged

Vulkan: some improvement on mul_mat_iq2_xs #18031

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
251642b
Some improvement on mul_mat_iq2_xs
lovedheart Dec 14, 2025
31342c2
Fix trailing whitespace
lovedheart Dec 15, 2025
05ec473
Merge branch 'ggml-org:master' into lovedheart-mul_mat_iq2_xs_improve
lovedheart Dec 15, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
66 changes: 42 additions & 24 deletions ggml/src/ggml-vulkan/vulkan-shaders/mul_mat_vec_iq2_xs.comp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,36 +11,54 @@ void calc_superblock(const uint a_offset, const uint b_offset, const uint itid,
const uint y_idx = i * QUANT_K + 16 * itid;
const uint nibble_shift = 4 * (itid & 1);
const uint ib32 = itid / 2; // 0..7

uint ibi = a_offset / QUANT_K + first_row * num_blocks_per_row + i;
// Precompute db multiplication factors
float db_vals[NUM_ROWS];
[[unroll]] for (uint n = 0; n < num_rows; ++n) {
const float d = float(data_a[ibi].d);
const uint scale = (data_a[ibi].scales[ib32] >> nibble_shift) & 0xF;
const float db = d * (0.5 + scale) * 0.25;

const uint scale_raw = data_a[ibi].scales[ib32];
const uint scale = (scale_raw >> nibble_shift) & 0xF;
// Merge constant calculations d * (0.5 + scale) * 0.25 = d*0.125 + d*scale*0.25
db_vals[n] = d * (0.125f + float(scale) * 0.25f);
ibi += num_blocks_per_row;
}
ibi = a_offset / QUANT_K + first_row * num_blocks_per_row + i;
[[unroll]] for (uint n = 0; n < num_rows; ++n) {
// Preload grid and sign data for all l values
vec4 grid0_vals[2], grid1_vals[2];
uint sign_vals[2], sign7_vals[2];
[[unroll]] for (uint l = 0; l < 2; ++l) {
const uint qs = data_a[ibi].qs[2 * itid + l];
const uint sign = qs >> 9;
const uint sign7 = bitCount(sign);
const vec4 grid0 = vec4(unpack8(iq2xs_grid[qs & 511].x));
const vec4 grid1 = vec4(unpack8(iq2xs_grid[qs & 511].y));

[[unroll]] for (uint j = 0; j < NUM_COLS; ++j) {
vec4 b0 = vec4(data_b_v4[(j*p.batch_stride_b + b_offset + y_idx) / 4 + 2*l + 0]);
vec4 b4 = vec4(data_b_v4[(j*p.batch_stride_b + b_offset + y_idx) / 4 + 2*l + 1]);

FLOAT_TYPE sum =
fma(FLOAT_TYPE(b0.x), FLOAT_TYPE((sign & 1) != 0 ? -grid0.x : grid0.x),
fma(FLOAT_TYPE(b0.y), FLOAT_TYPE((sign & 2) != 0 ? -grid0.y : grid0.y),
fma(FLOAT_TYPE(b0.z), FLOAT_TYPE((sign & 4) != 0 ? -grid0.z : grid0.z),
fma(FLOAT_TYPE(b0.w), FLOAT_TYPE((sign & 8) != 0 ? -grid0.w : grid0.w),
fma(FLOAT_TYPE(b4.x), FLOAT_TYPE((sign & 16) != 0 ? -grid1.x : grid1.x),
fma(FLOAT_TYPE(b4.y), FLOAT_TYPE((sign & 32) != 0 ? -grid1.y : grid1.y),
fma(FLOAT_TYPE(b4.z), FLOAT_TYPE((sign & 64) != 0 ? -grid1.z : grid1.z),
fma(FLOAT_TYPE(b4.w), FLOAT_TYPE((sign7 & 1) != 0 ? -grid1.w : grid1.w),
FLOAT_TYPE(0.0)))))))));
temp[j][n] = fma(db, sum, temp[j][n]);
sign_vals[l] = qs >> 9;
sign7_vals[l] = bitCount(sign_vals[l]);
const uvec2 grid_data = iq2xs_grid[qs & 511];
grid0_vals[l] = vec4(unpack8(grid_data.x));
grid1_vals[l] = vec4(unpack8(grid_data.y));
}
// Preload B data for all j columns (reduce repeated index calculations)
[[unroll]] for (uint j = 0; j < NUM_COLS; ++j) {
FLOAT_TYPE sum = FLOAT_TYPE(0.0);
[[unroll]] for (uint l = 0; l < 2; ++l) {
const uint sign = sign_vals[l];
const uint sign7 = sign7_vals[l];
const vec4 grid0 = grid0_vals[l];
const vec4 grid1 = grid1_vals[l];
// Precompute indices
const uint b_idx = (j * p.batch_stride_b + b_offset + y_idx) / 4 + 2 * l;
const vec4 b0 = vec4(data_b_v4[b_idx + 0]);
const vec4 b4 = vec4(data_b_v4[b_idx + 1]);
sum +=
fma(FLOAT_TYPE(b0.x), FLOAT_TYPE((sign & 1) != 0 ? -grid0.x : grid0.x),
fma(FLOAT_TYPE(b0.y), FLOAT_TYPE((sign & 2) != 0 ? -grid0.y : grid0.y),
fma(FLOAT_TYPE(b0.z), FLOAT_TYPE((sign & 4) != 0 ? -grid0.z : grid0.z),
fma(FLOAT_TYPE(b0.w), FLOAT_TYPE((sign & 8) != 0 ? -grid0.w : grid0.w),
fma(FLOAT_TYPE(b4.x), FLOAT_TYPE((sign & 16) != 0 ? -grid1.x : grid1.x),
fma(FLOAT_TYPE(b4.y), FLOAT_TYPE((sign & 32) != 0 ? -grid1.y : grid1.y),
fma(FLOAT_TYPE(b4.z), FLOAT_TYPE((sign & 64) != 0 ? -grid1.z : grid1.z),
fma(FLOAT_TYPE(b4.w), FLOAT_TYPE((sign7 & 1) != 0 ? -grid1.w : grid1.w),
FLOAT_TYPE(0.0)))))))));
}
temp[j][n] = fma(FLOAT_TYPE(db_vals[n]), sum, temp[j][n]);
}
ibi += num_blocks_per_row;
}
Expand Down
Loading