Skip to content

cuda: tall one-column mat-vec for Q8_0/Q4_0/Q2_0/Q4_K/Q6_K on Hopper, and allow folded Gemma 4 weights #413

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
bri-prism merged 2 commits into from
Oct 29, 2026
Merged

cuda: tall one-column mat-vec for Q8_0/Q4_0/Q2_0/Q4_K/Q6_K on Hopper, and allow folded Gemma 4 weights #413

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4cc59ab
cuda: extend the tall mmvq geometry to Q8_0/Q4_0/Q2_0/Q4_K/Q6_K rows>…
bri-prism Oct 28, 2026
17c1fa9
model: allow prism.hadamard folded weights for Gemma 4
bri-prism Oct 28, 2026
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
13 changes: 11 additions & 2 deletions ggml/src/ggml-cuda/mmvq.cu
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -582,6 +582,12 @@ static constexpr __host__ __device__ int calc_rows_per_block(ggml_type type, int
// rows of the weight matrix per CTA for a tall one-column mat-vec (see should_use_tall below)
#define MMVQ_TALL_ROWS_PER_BLOCK 8

// Types besides PQ2_0 that also take the tall geometry (one instantiation more each): the common quantized types.
static constexpr bool mmvq_tall_ext_type(ggml_type type) {
return type == GGML_TYPE_Q8_0 || type == GGML_TYPE_Q4_0 || type == GGML_TYPE_Q2_0 ||
type == GGML_TYPE_Q4_K || type == GGML_TYPE_Q6_K;
}

template <ggml_type type, int ncols_dst, bool has_fusion, bool has_gate, bool small_k = false, bool halve_iters = false, bool y_soa = false, bool tall = false>
__launch_bounds__(calc_nwarps(type, ncols_dst, get_device_table_id(), small_k, halve_iters)*ggml_cuda_get_physical_warp_size(), 1)
static __global__ void mul_mat_vec_q(
Expand Down Expand Up @@ -1343,8 +1349,11 @@ static void mul_mat_vec_q_switch_ncols_dst(
// (Bonsai 2 9B LM head, 248320 x 4096: 249 us, about 1.1 TB/s on an H200). Eight rows per CTA keep the same K
// partition and reduction order for every row (each row's sum is bit-identical) and cut that to 121 us; the
// 4096-12288 row trunk projections gain 28-42% as well. Matrices under 4096 rows have too few CTAs for it.
// The same geometry helps any type whose one-column default gives one 128-thread CTA per row (tall output heads).
// GGML_CUDA_MMVQ_TALL_EXT=0 keeps it PQ2_0-only.
const auto should_use_tall = [&] {
return type == GGML_TYPE_PQ2_0 && table_id == MMVQ_PARAMETERS_GENERIC && GGML_CUDA_CC_IS_NVIDIA(cc) &&
static const bool ext = !getenv("GGML_CUDA_MMVQ_TALL_EXT") || atoi(getenv("GGML_CUDA_MMVQ_TALL_EXT")) != 0;
return (type == GGML_TYPE_PQ2_0 || (ext && mmvq_tall_ext_type(type))) && table_id == MMVQ_PARAMETERS_GENERIC && GGML_CUDA_CC_IS_NVIDIA(cc) &&
cc >= GGML_CUDA_CC_HOPPER && cc < GGML_CUDA_CC_BLACKWELL && !has_ids && !y_soa && nrows_x >= 4096 &&
nrows_x % MMVQ_TALL_ROWS_PER_BLOCK == 0; // whole CTAs: rows past the end would be read, not only skipped
};
Expand Down Expand Up @@ -1388,7 +1397,7 @@ static void mul_mat_vec_q_switch_ncols_dst(
launch(std::true_type{}, std::false_type{}, std::false_type{});
} else if (should_halve_iters()) {
launch(std::false_type{}, std::true_type{}, std::false_type{});
} else if constexpr (type == GGML_TYPE_PQ2_0) {
} else if constexpr (type == GGML_TYPE_PQ2_0 || mmvq_tall_ext_type(type)) {
if (should_use_tall()) {
launch(std::false_type{}, std::false_type{}, std::true_type{});
} else {
Expand Down
1 change: 1 addition & 0 deletions src/llama-model.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1287,6 +1287,7 @@ void llama_model_base::load_hparams(llama_model_loader & ml) {
case LLM_ARCH_QWEN35MOE:
case LLM_ARCH_QWEN3NEXT:
case LLM_ARCH_DSPARK:
case LLM_ARCH_GEMMA4:
break;
default:
throw std::runtime_error(format(
Expand Down
Loading