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Fix Vulkan Quantized Matrix Vector Multiplication on AMD GPUs when ncols < 64 #8855

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Merged
merged 2 commits into from
Aug 5, 2024
Merged

Fix Vulkan Quantized Matrix Vector Multiplication on AMD GPUs when ncols < 64 #8855

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ecabd54
Fix Vulkan mul mat vec invalid results when ncols < warp size
0cc4m Aug 4, 2024
6c75cb9
Only run backend ops mul mat vec block size test if block size not al…
0cc4m Aug 4, 2024
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13 changes: 10 additions & 3 deletions ggml/src/vulkan-shaders/mul_mat_vec.comp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,15 +16,22 @@ void main() {
const uint row = gl_WorkGroupID.x + gl_NumWorkGroups.x * gl_WorkGroupID.z;
const uint tid = gl_LocalInvocationID.x;

// There are not enough cols to use all threads
if (tid >= p.ncols) {
return;
}

const uint block_size = min(p.ncols, BLOCK_SIZE);

uint a_offset, b_offset, d_offset;
get_offsets(a_offset, b_offset, d_offset);

const uint y_offset = QUANT_R == 1 ? 1 : QUANT_K/2;

tmp[tid] = FLOAT_TYPE(0.0f);

[[unroll]] for (uint i = 0; i < p.ncols/BLOCK_SIZE; i += 2) {
const uint col = i*BLOCK_SIZE + 2*tid;
[[unroll]] for (uint i = 0; i < p.ncols/block_size; i += 2) {
const uint col = i*block_size + 2*tid;
const uint ib = (row*p.ncols + col)/QUANT_K; // block index
const uint iqs = (col%QUANT_K)/QUANT_R; // quant index
const uint iybs = col - col%QUANT_K; // y block start index
Expand All @@ -38,7 +45,7 @@ void main() {

// sum up partial sums and write back result
barrier();
[[unroll]] for (uint s = BLOCK_SIZE/2; s > 0; s >>= 1) {
[[unroll]] for (uint s = block_size/2; s > 0; s >>= 1) {
if (tid < s) {
tmp[tid] += tmp[tid + s];
}
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7 changes: 4 additions & 3 deletions tests/test-backend-ops.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2271,9 +2271,10 @@ static bool test_backend(ggml_backend_t backend, test_mode mode, const char * op

for (ggml_type type_a : other_types) {
for (ggml_type type_b : {GGML_TYPE_F32}) {

test_cases.emplace_back(new test_mul_mat(type_a, type_b, 16, 1, ggml_blck_size(type_a), { 1, 1}, {1, 1}));
test_cases.emplace_back(new test_mul_mat(type_a, type_b, 16, 1, 256, { 1, 1}, {1, 1}));
if (ggml_blck_size(type_a) != 256) {
test_cases.emplace_back(new test_mul_mat(type_a, type_b, 16, 1, ggml_blck_size(type_a), {1, 1}, {1, 1}));
}
test_cases.emplace_back(new test_mul_mat(type_a, type_b, 16, 1, 256, {1, 1}, {1, 1}));
}
}

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