ggml-webgpu: add Q1_0 support (#22374)

* add fast matmul matvec q1_0 kernel

* ggml-webgpu: drop redundant zero-fills in Q1_0 shmem init
This commit is contained in:
Rithik Sharma
2026-04-27 15:50:59 -07:00
committed by GitHub
parent 983ca8992e
commit 434b2a1ff6
5 changed files with 94 additions and 2 deletions
@@ -27,6 +27,24 @@ fn copy_elements(src_base: u32, dst_base: u32, offset: u32) {
}
#endif
#ifdef Q1_0
fn copy_elements(src_base: u32, dst_base: u32, offset: u32) {
let block_byte_base = (src_base + offset) * 18;
let d = load_f16_as_f32_at_src(block_byte_base);
for (var j: u32 = 0u; j < 4u; j++) {
let q_packed = load_u32_at_src(block_byte_base + 2u + j * 4u);
let dst_base128 = dst_base + offset * 128u + j * 32u;
for (var k: u32 = 0; k < 4u; k++) {
let q_byte = get_byte(q_packed, k);
for (var bit: u32 = 0; bit < 8u; bit++) {
let w = select(-d, d, ((q_byte >> bit) & 1u) != 0u);
dst[dst_base128 + k * 8u + bit] = w;
}
}
}
}
#endif
#ifdef Q4_0
fn copy_elements(src_base: u32, dst_base: u32, offset: u32) {
let block_byte_base = (src_base + offset) * 18; // Block stride: 18 bytes
@@ -61,6 +61,39 @@ fn init_shmem_src1(thread_id: u32, batch_offset: u32, offset_n: u32, k_outer: u3
#endif // INIT_SRC1_SHMEM_FLOAT
#endif
#ifdef INIT_SRC0_SHMEM_Q1_0
const BLOCK_SIZE = 128u;
const BLOCK_SIZE_BYTES = 18u;
const NQ = 8u; // 8 weights (1 byte of qs) per thread per iteration
fn init_shmem_src0(thread_id: u32, batch_offset: u32, offset_m: u32, k_outer: u32) {
for (var i = thread_id * NQ; i < TILE_SRC0_SHMEM; i += TOTAL_WORKGROUP_SIZE * NQ) {
let tile_m = i / TILE_K;
let tile_k_start = i % TILE_K;
let global_m = offset_m + tile_m;
let global_k_start = k_outer + tile_k_start;
if (global_m >= params.m) {
break;
}
let block_k = global_k_start / BLOCK_SIZE;
let byte_in_block = (global_k_start % BLOCK_SIZE) / 8u;
let src0_idx = batch_offset + global_m * params.stride_01 + block_k;
let block_byte_base = src0_idx * BLOCK_SIZE_BYTES;
let d = load_f16_at_src0(block_byte_base);
let q_byte = load_u32_at_src0(block_byte_base + 2u + byte_in_block) & 0xFFu;
for (var bit = 0u; bit < NQ; bit++) {
let global_k = global_k_start + bit;
if (global_k < params.k) {
shmem[i + bit] = select(-d, d, ((q_byte >> bit) & 1u) != 0u);
}
}
}
}
#endif // INIT_SRC0_SHMEM_Q1_0
#ifdef INIT_SRC0_SHMEM_Q4_0
const BLOCK_SIZE = 32u;
const BLOCK_SIZE_BYTES = 18u;
@@ -128,6 +128,38 @@ fn main(
}
#endif
#ifdef MUL_ACC_Q1_0
#define BLOCK_SIZE 128
#define BLOCK_SIZE_BYTES 18
#define THREADS_PER_BLOCK 16
#define ELEMS_PER_THREAD (BLOCK_SIZE/THREADS_PER_BLOCK)
let num_blocks = params.k / BLOCK_SIZE;
let thread_within_block = thread_id % THREADS_PER_BLOCK;
for (var block = thread_id / THREADS_PER_BLOCK; block < num_blocks; block += WG_SIZE / THREADS_PER_BLOCK) {
let x_base = src1_idx_base + block * BLOCK_SIZE + thread_within_block * ELEMS_PER_THREAD;
var x_block: array<f32, ELEMS_PER_THREAD>;
for (var i = 0u; i < ELEMS_PER_THREAD; i++) {
x_block[i] = f32(src1[x_base + i]);
}
for (var row = 0u; row < OUTPUTS_PER_WG; row++) {
let output_row = row_base + row;
if (output_row < params.m) {
let block_byte_base = (src0_batch_offset + output_row * params.stride_01 + block) * BLOCK_SIZE_BYTES;
let d = f32(load_f16_at_src0(block_byte_base));
let q_byte = load_u32_at_src0(block_byte_base + 2u + thread_within_block) & 0xFFu;
var row_sum = 0.0;
for (var bit = 0u; bit < 8u; bit++) {
let w = select(-d, d, ((q_byte >> bit) & 1u) != 0u);
row_sum += w * x_block[bit];
}
acc[row] += row_sum;
}
}
}
#endif
#ifdef MUL_ACC_Q4_0
#define BLOCK_SIZE 32
#define BLOCK_SIZE_BYTES 18