vulkan: optimize mul_mat_id loading row ids into shared memory (#15427)

- Spread the work across the whole workgroup. Using more threads seems to
far outweigh the synchronization overhead.
- Specialize the code for when the division is by a power of two.
This commit is contained in:
Jeff Bolz
2025-08-23 01:31:54 -05:00
committed by GitHub
parent e92734d51b
commit 330c3d2d21
3 changed files with 133 additions and 81 deletions

View File

@@ -2168,9 +2168,9 @@ static void ggml_vk_load_shaders(vk_device& device) {
s_mmq_wg_denoms_k = { 32, 64, 1 };
// spec constants and tile sizes for quant matmul_id
l_warptile_mmqid = { 256, 128, 128, 16, 0 };
m_warptile_mmqid = { 256, 128, 64, 16, 0 };
s_warptile_mmqid = { 256, 128, 64, 16, 0 };
l_warptile_mmqid = { 256, 128, 128, 16, 0, device->subgroup_size };
m_warptile_mmqid = { 256, 128, 64, 16, 0, device->subgroup_size };
s_warptile_mmqid = { 256, 128, 64, 16, 0, device->subgroup_size };
l_mmqid_wg_denoms = { 128, 128, 1 };
m_mmqid_wg_denoms = { 128, 64, 1 };
s_mmqid_wg_denoms = { 128, 64, 1 };

View File

@@ -103,16 +103,74 @@ layout (constant_id = 10) const uint WARP = 32;
shared FLOAT_TYPE buf_a[BM * SHMEM_STRIDE];
shared FLOAT_TYPE buf_b[BN * SHMEM_STRIDE];
#define NUM_WARPS (BLOCK_SIZE / WARP)
#ifdef MUL_MAT_ID
shared u16vec2 row_ids[4096];
uint _ne1;
#ifdef COOPMAT
shared uint _ne1_sh;
shared uvec4 ballots_sh[NUM_WARPS];
void load_row_ids(uint expert_idx, bool nei0_is_pow2) {
_ne1 = 0;
uint num_elements = p.nei1 * p.nei0;
uint nei0shift = findLSB(p.nei0);
uint ids[16];
uint iter = 0;
for (uint j = 0; j < num_elements; j += BLOCK_SIZE) {
// prefetch up to 16 elements
if (iter == 0) {
[[unroll]] for (uint k = 0; k < 16; ++k) {
uint i = j + gl_LocalInvocationIndex + k*BLOCK_SIZE;
bool in_range = i < num_elements;
uint ii1;
if (nei0_is_pow2) {
ii1 = i >> nei0shift;
} else {
ii1 = i / p.nei0;
}
uint ii0 = i - ii1 * p.nei0;
ids[k] = in_range ? data_ids[ii1*p.nbi1 + ii0] : 0;
}
}
uint i = j + gl_LocalInvocationIndex;
bool in_range = i < num_elements;
uint ii1;
if (nei0_is_pow2) {
ii1 = i >> nei0shift;
} else {
ii1 = i / p.nei0;
}
uint ii0 = i - ii1 * p.nei0;
uint id = ids[iter++];
uvec4 ballot = subgroupBallot(in_range && id == expert_idx);
ballots_sh[gl_SubgroupID] = ballot;
barrier();
uint subgroup_base = 0;
uint total = 0;
for (uint k = 0; k < gl_NumSubgroups; ++k) {
if (k == gl_SubgroupID) {
subgroup_base = total;
}
total += subgroupBallotBitCount(ballots_sh[k]);
}
barrier();
uint idx = subgroup_base + subgroupBallotExclusiveBitCount(ballot);
if (in_range && id == expert_idx) {
row_ids[_ne1 + idx] = u16vec2(ii0, ii1);
}
_ne1 += total;
iter &= 15;
}
barrier();
}
#endif
#endif // MUL_MAT_ID
#define NUM_WARPS (BLOCK_SIZE / WARP)
#ifdef COOPMAT
shared ACC_TYPE coopmat_stage[TM * TN * NUM_WARPS];
#endif
@@ -178,44 +236,11 @@ void main() {
#ifdef MUL_MAT_ID
#ifdef COOPMAT
// Spread the search across all elements in the first subgroup
if (gl_SubgroupID == 0) {
_ne1 = 0;
uint num_elements = p.nei1 * p.nei0;
uint ids[16];
uint iter = 0;
for (uint j = 0; j < num_elements; j += gl_SubgroupSize) {
// prefetch up to 16 elements
if (iter == 0) {
[[unroll]] for (uint k = 0; k < 16; ++k) {
uint i = j + gl_SubgroupInvocationID + k*gl_SubgroupSize;
bool in_range = i < num_elements;
uint ii1 = i / p.nei0;
uint ii0 = i % p.nei0;
ids[k] = in_range ? data_ids[ii1*p.nbi1 + ii0] : 0;
}
}
uint i = j + gl_SubgroupInvocationID;
bool in_range = i < num_elements;
uint ii1 = i / p.nei0;
uint ii0 = i % p.nei0;
uint id = ids[iter++];
uvec4 ballot = subgroupBallot(in_range && id == expert_idx);
uint idx = subgroupBallotExclusiveBitCount(ballot);
if (in_range && id == expert_idx) {
row_ids[_ne1 + idx] = u16vec2(ii0, ii1);
}
_ne1 += subgroupBallotBitCount(ballot);
iter &= 15;
}
_ne1_sh = _ne1;
if (bitCount(p.nei0) == 1) {
load_row_ids(expert_idx, true);
} else {
load_row_ids(expert_idx, false);
}
barrier();
_ne1 = _ne1_sh;
#else
_ne1 = 0;
for (uint ii1 = 0; ii1 < p.nei1; ii1++) {

View File

@@ -19,6 +19,7 @@
#endif
#include "types.comp"
#include "utils.comp"
layout(local_size_x_id = 0, local_size_y = 1, local_size_z = 1) in;
@@ -99,7 +100,8 @@ layout(buffer_reference, std430, buffer_reference_align = 2) buffer decodeBufB {
};
uint _ne1;
shared uint _ne1_sh;
layout (constant_id = 5) const uint subgroup_size = 32;
shared uvec4 ballots_sh[BLOCK_SIZE / subgroup_size];
B_TYPE decodeFuncB(const in decodeBufB bl, const in uint blockCoords[2], const in uint coordInBlock[2])
{
@@ -128,6 +130,64 @@ D_TYPE perElemOpD(const in uint32_t r, const in uint32_t c, const in D_TYPE elem
return elem;
}
void load_row_ids(uint expert_idx, bool nei0_is_pow2) {
_ne1 = 0;
uint num_elements = p.nei1 * p.nei0;
uint nei0shift = findLSB(p.nei0);
uint ids[16];
uint iter = 0;
for (uint j = 0; j < num_elements; j += BLOCK_SIZE) {
// prefetch up to 16 elements
if (iter == 0) {
[[unroll]] for (uint k = 0; k < 16; ++k) {
uint i = j + gl_LocalInvocationIndex + k*BLOCK_SIZE;
bool in_range = i < num_elements;
uint ii1;
if (nei0_is_pow2) {
ii1 = i >> nei0shift;
} else {
ii1 = i / p.nei0;
}
uint ii0 = i - ii1 * p.nei0;
ids[k] = in_range ? data_ids[ii1*p.nbi1 + ii0] : 0;
}
}
uint i = j + gl_LocalInvocationIndex;
bool in_range = i < num_elements;
uint ii1;
if (nei0_is_pow2) {
ii1 = i >> nei0shift;
} else {
ii1 = i / p.nei0;
}
uint ii0 = i - ii1 * p.nei0;
uint id = ids[iter++];
uvec4 ballot = subgroupBallot(in_range && id == expert_idx);
ballots_sh[gl_SubgroupID] = ballot;
barrier();
uint subgroup_base = 0;
uint total = 0;
for (uint k = 0; k < gl_NumSubgroups; ++k) {
if (k == gl_SubgroupID) {
subgroup_base = total;
}
total += subgroupBallotBitCount(ballots_sh[k]);
}
barrier();
uint idx = subgroup_base + subgroupBallotExclusiveBitCount(ballot);
if (in_range && id == expert_idx) {
row_ids[_ne1 + idx] = u16vec4(fastmod(ii0, p.ne11), ii1, ii0, 0);
}
_ne1 += total;
iter &= 15;
}
barrier();
}
#endif
void main() {
@@ -157,45 +217,12 @@ void main() {
const uint ic = gl_WorkGroupID.y;
#ifdef MUL_MAT_ID
// Spread the search across all elements in the first subgroup
if (gl_SubgroupID == 0) {
_ne1 = 0;
uint num_elements = p.nei1 * p.nei0;
uint ids[16];
uint iter = 0;
for (uint j = 0; j < num_elements; j += gl_SubgroupSize) {
// prefetch up to 16 elements
if (iter == 0) {
[[unroll]] for (uint k = 0; k < 16; ++k) {
uint i = j + gl_SubgroupInvocationID + k*gl_SubgroupSize;
bool in_range = i < num_elements;
uint ii1 = i / p.nei0;
uint ii0 = i % p.nei0;
ids[k] = in_range ? data_ids[ii1*p.nbi1 + ii0] : 0;
}
}
uint i = j + gl_SubgroupInvocationID;
bool in_range = i < num_elements;
uint ii1 = i / p.nei0;
uint ii0 = i % p.nei0;
uint id = ids[iter++];
uvec4 ballot = subgroupBallot(in_range && id == expert_idx);
uint idx = subgroupBallotExclusiveBitCount(ballot);
if (in_range && id == expert_idx) {
row_ids[_ne1 + idx] = u16vec4(ii0 % p.ne11, ii1, ii0, 0);
}
_ne1 += subgroupBallotBitCount(ballot);
iter &= 15;
}
_ne1_sh = _ne1;
if (bitCount(p.nei0) == 1) {
load_row_ids(expert_idx, true);
} else {
load_row_ids(expert_idx, false);
}
barrier();
_ne1 = _ne1_sh;
// Workgroup has no work
if (ic * BN >= _ne1) return;
#endif