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vulkan: fix coopmat2 flash attention for non-contiguous inputs (ggerg…
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…anov#11281)

Add code similar to mul_mm_cm2 to force alignment of strides, to avoid
a performance regression.

Add noncontiguous FA tests in test-backend-ops.

Fixes ggerganov#11268.
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@jeffbolznv
jeffbolznv authored Jan 18, 2025
1 parent 3edfa7d commit 44e18ef
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Showing 3 changed files with 82 additions and 12 deletions.
43 changes: 37 additions & 6 deletions ggml/src/ggml-vulkan/ggml-vulkan.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -386,10 +386,13 @@ struct vk_flash_attn_push_constants {
uint32_t nev3;
uint32_t nem1;

uint32_t nb01;
uint32_t nb02;
uint32_t nb03;
uint32_t nb11;
uint32_t nb12;
uint32_t nb13;
uint32_t nb21;
uint32_t nb22;
uint32_t nb23;
uint32_t nb31;
Expand Down Expand Up @@ -4809,7 +4812,14 @@ static void ggml_vk_flash_attn(ggml_backend_vk_context * ctx, vk_context& subctx
}
assert(pipelines);

bool aligned = (KV % pipelines[1]->align) == 0;
const uint32_t q_stride = (uint32_t)(nbq1 / ggml_type_size(q->type));
const uint32_t k_stride = (uint32_t)(nbk1 / ggml_type_size(k->type));
const uint32_t v_stride = (uint32_t)(nbv1 / ggml_type_size(v->type));

bool aligned = (KV % pipelines[1]->align) == 0 &&
// the "aligned" shader variant will forcibly align strides, for performance
(q_stride & 7) == 0 && (k_stride & 7) == 0 && (v_stride & 7) == 0;

vk_pipeline pipeline = pipelines[aligned];
assert(pipeline);

Expand Down Expand Up @@ -4845,15 +4855,15 @@ static void ggml_vk_flash_attn(ggml_backend_vk_context * ctx, vk_context& subctx

if (ctx->device->uma) {
ggml_vk_host_get(ctx->device, q->data, d_Q, q_buf_offset);
ggml_vk_host_get(ctx->device, k->data, d_K, q_buf_offset);
ggml_vk_host_get(ctx->device, v->data, d_V, q_buf_offset);
ggml_vk_host_get(ctx->device, dst->data, d_D, q_buf_offset);
ggml_vk_host_get(ctx->device, k->data, d_K, k_buf_offset);
ggml_vk_host_get(ctx->device, v->data, d_V, v_buf_offset);
ggml_vk_host_get(ctx->device, dst->data, d_D, d_buf_offset);
Q_uma = d_Q != nullptr;
K_uma = d_K != nullptr;
V_uma = d_V != nullptr;
D_uma = d_D != nullptr;
if (mask) {
ggml_vk_host_get(ctx->device, mask->data, d_M, q_buf_offset);
ggml_vk_host_get(ctx->device, mask->data, d_M, m_buf_offset);
M_uma = d_M != nullptr;
}
}
Expand Down Expand Up @@ -4891,7 +4901,18 @@ static void ggml_vk_flash_attn(ggml_backend_vk_context * ctx, vk_context& subctx
}
}

const vk_flash_attn_push_constants pc = { N, KV, (uint32_t)ne1, (uint32_t)ne2, (uint32_t)ne3, (uint32_t)neq2, (uint32_t)neq3, (uint32_t)nek2, (uint32_t)nek3, (uint32_t)nev2, (uint32_t)nev3, nem1, (uint32_t)nbq2, (uint32_t)nbq3, (uint32_t)nbk2, (uint32_t)nbk3, (uint32_t)nbv2, (uint32_t)nbv3, nbm1, scale, max_bias, logit_softcap, mask != nullptr, n_head_log2, m0, m1 };
const vk_flash_attn_push_constants pc = { N, KV,
(uint32_t)ne1, (uint32_t)ne2, (uint32_t)ne3,
(uint32_t)neq2, (uint32_t)neq3,
(uint32_t)nek2, (uint32_t)nek3,
(uint32_t)nev2, (uint32_t)nev3,
nem1,
q_stride, (uint32_t)nbq2, (uint32_t)nbq3,
k_stride, (uint32_t)nbk2, (uint32_t)nbk3,
v_stride, (uint32_t)nbv2, (uint32_t)nbv3,
nbm1,
scale, max_bias, logit_softcap,
mask != nullptr, n_head_log2, m0, m1 };
ggml_vk_dispatch_pipeline(ctx, subctx, pipeline,
{
vk_subbuffer{d_Q, q_buf_offset, VK_WHOLE_SIZE},
Expand Down Expand Up @@ -8668,6 +8689,7 @@ static void ggml_vk_check_results_1(ggml_tensor * tensor) {
ggml_tensor * src0 = tensor->src[0];
ggml_tensor * src1 = tensor->src[1];
ggml_tensor * src2 = tensor->src[2];
ggml_tensor * src3 = tensor->src[3];

void * tensor_data = tensor->data;

Expand Down Expand Up @@ -8730,6 +8752,9 @@ static void ggml_vk_check_results_1(ggml_tensor * tensor) {
if (src2 != nullptr) {
std::cerr << "src2=" << src2 << " src2->name=" << src2->name << " op=" << ggml_op_name(src2->op) << " type=" << ggml_type_name(src2->type) << " ne0=" << src2->ne[0] << " nb0=" << src2->nb[0] << " ne1=" << src2->ne[1] << " nb1=" << src2->nb[1] << " ne2=" << src2->ne[2] << " nb2=" << src2->nb[2] << " ne3=" << src2->ne[3] << " nb3=" << src2->nb[3] << " offset=" << src2->view_offs << std::endl;
}
if (src3 != nullptr) {
std::cerr << "src3=" << src3 << " src3->name=" << src3->name << " op=" << ggml_op_name(src3->op) << " type=" << ggml_type_name(src3->type) << " ne0=" << src3->ne[0] << " nb0=" << src3->nb[0] << " ne1=" << src3->ne[1] << " nb1=" << src3->nb[1] << " ne2=" << src3->ne[2] << " nb2=" << src3->nb[2] << " ne3=" << src3->ne[3] << " nb3=" << src3->nb[3] << " offset=" << src3->view_offs << std::endl;
}
std::cerr << "First error: result=" << first_error_result << " correct=" << first_error_correct << " i3=" << first_error[3] << " i2=" << first_error[2] << " i1=" << first_error[1] << " i0=" << first_error[0] << std::endl;
std::cerr << std::endl << "Result:" << std::endl;
ggml_vk_print_tensor_area(tensor, tensor_data, i0, i1, i2, i3);
Expand Down Expand Up @@ -8774,6 +8799,9 @@ static void ggml_vk_check_results_1(ggml_tensor * tensor) {
if (src2 != nullptr) {
std::cerr << "src2=" << src2 << " op=" << ggml_op_name(src2->op) << " type=" << ggml_type_name(src2->type) << " ne0=" << src2->ne[0] << " nb0=" << src2->nb[0] << " ne1=" << src2->ne[1] << " nb1=" << src2->nb[1] << " ne2=" << src2->ne[2] << " nb2=" << src2->nb[2] << " ne3=" << src2->ne[3] << " nb3=" << src2->nb[3] << " offset=" << src2->view_offs << std::endl;
}
if (src3 != nullptr) {
std::cerr << "src3=" << src3 << " op=" << ggml_op_name(src3->op) << " type=" << ggml_type_name(src3->type) << " ne0=" << src3->ne[0] << " nb0=" << src3->nb[0] << " ne1=" << src3->ne[1] << " nb1=" << src3->nb[1] << " ne2=" << src3->ne[2] << " nb2=" << src3->nb[2] << " ne3=" << src3->ne[3] << " nb3=" << src3->nb[3] << " offset=" << src3->view_offs << std::endl;
}
std::cerr << "First error: result=" << first_error_result << " correct=" << first_error_correct << " i3=" << first_error[3] << " i2=" << first_error[2] << " i1=" << first_error[1] << " i0=" << first_error[0] << std::endl;
std::cerr << std::endl << "Result:" << std::endl;
ggml_vk_print_tensor_area(tensor, tensor_data, 5, 5, 0, 0);
Expand All @@ -8796,6 +8824,9 @@ static void ggml_vk_check_results_1(ggml_tensor * tensor) {
if (src2 != nullptr) {
std::cerr << "src2=" << src2 << " op=" << ggml_op_name(src2->op) << " type=" << ggml_type_name(src2->type) << " ne0=" << src2->ne[0] << " nb0=" << src2->nb[0] << " ne1=" << src2->ne[1] << " nb1=" << src2->nb[1] << " ne2=" << src2->ne[2] << " nb2=" << src2->nb[2] << " ne3=" << src2->ne[3] << " nb3=" << src2->nb[3] << " offset=" << src2->view_offs << std::endl;
}
if (src3 != nullptr) {
std::cerr << "src3=" << src3 << " op=" << ggml_op_name(src3->op) << " type=" << ggml_type_name(src3->type) << " ne0=" << src3->ne[0] << " nb0=" << src3->nb[0] << " ne1=" << src3->ne[1] << " nb1=" << src3->nb[1] << " ne2=" << src3->ne[2] << " nb2=" << src3->nb[2] << " ne3=" << src3->ne[3] << " nb3=" << src3->nb[3] << " offset=" << src3->view_offs << std::endl;
}
std::cerr << "First error: result=" << first_error_result << " correct=" << first_error_correct << " i3=" << first_error[3] << " i2=" << first_error[2] << " i1=" << first_error[1] << " i0=" << first_error[0] << std::endl;
std::cerr << std::endl << "Result:" << std::endl;
ggml_vk_print_tensor_area(tensor, tensor_data, first_error[0], first_error[1], first_error[2], first_error[3]);
Expand Down
20 changes: 20 additions & 0 deletions ggml/src/ggml-vulkan/vulkan-shaders/flash_attn_cm2.comp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,10 +42,13 @@ layout (push_constant) uniform parameter {
uint32_t nev3;
uint32_t nem1;

uint32_t nb01;
uint32_t nb02;
uint32_t nb03;
uint32_t nb11;
uint32_t nb12;
uint32_t nb13;
uint32_t nb21;
uint32_t nb22;
uint32_t nb23;
uint32_t nb31;
Expand Down Expand Up @@ -146,6 +149,23 @@ void main() {
tensorLayoutK = setTensorLayoutDimensionNV(tensorLayoutK, KV, D);
tensorLayoutV = setTensorLayoutDimensionNV(tensorLayoutV, KV, D);

// nb?1 are already divided by the type size and are in units of elements
uint32_t q_stride = p.nb01;
uint32_t k_stride = p.nb11;
uint32_t v_stride = p.nb21;
// hint to the compiler that strides are aligned for the aligned variant of the shader
if (Clamp != gl_CooperativeMatrixClampModeConstantNV)
{
q_stride &= ~7;
#if !defined(BLOCK_SIZE)
k_stride &= ~7;
v_stride &= ~7;
#endif
}
tensorLayoutQ = setTensorLayoutStrideNV(tensorLayoutQ, q_stride, 1);
tensorLayoutK = setTensorLayoutStrideNV(tensorLayoutK, k_stride, 1);
tensorLayoutV = setTensorLayoutStrideNV(tensorLayoutV, v_stride, 1);

coopmat<Q_TYPE, gl_ScopeWorkgroup, Br, D, gl_MatrixUseA> Q;
coopmat<float16_t, gl_ScopeWorkgroup, Br, D, gl_MatrixUseA> Qf16;

Expand Down
31 changes: 25 additions & 6 deletions tests/test-backend-ops.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3046,9 +3046,10 @@ struct test_flash_attn_ext : public test_case {
const float logit_softcap; // Gemma 2

const ggml_type type_KV;
std::array<int32_t, 4> permute;

std::string vars() override {
return VARS_TO_STR8(hs, nh, kv, nb, mask, max_bias, logit_softcap, type_KV);
return VARS_TO_STR9(hs, nh, kv, nb, mask, max_bias, logit_softcap, type_KV, permute);
}

double max_nmse_err() override {
Expand All @@ -3063,19 +3064,33 @@ struct test_flash_attn_ext : public test_case {
}

test_flash_attn_ext(int64_t hs = 128, int64_t nh = 32, int64_t kv = 96, int64_t nb = 8,
bool mask = true, float max_bias = 0.0f, float logit_softcap = 0.0f, ggml_type type_KV = GGML_TYPE_F16)
: hs(hs), nh(nh), kv(kv), nb(nb), mask(mask), max_bias(max_bias), logit_softcap(logit_softcap), type_KV(type_KV) {}
bool mask = true, float max_bias = 0.0f, float logit_softcap = 0.0f, ggml_type type_KV = GGML_TYPE_F16,
std::array<int32_t, 4> permute = {0, 1, 2, 3})
: hs(hs), nh(nh), kv(kv), nb(nb), mask(mask), max_bias(max_bias), logit_softcap(logit_softcap), type_KV(type_KV), permute(permute) {}

ggml_tensor * build_graph(ggml_context * ctx) override {
const int64_t hs_padded = GGML_PAD(hs, ggml_blck_size(type_KV));

ggml_tensor * q = ggml_new_tensor_4d(ctx, GGML_TYPE_F32, hs_padded, nb, nh, 1);
auto const &create_permuted = [&](ggml_type type, int64_t ne0, int64_t ne1, int64_t ne2, int64_t ne3) -> ggml_tensor * {
int64_t ne[4] = {ne0, ne1, ne2, ne3};
int64_t ne_perm[4];
for (int i = 0; i < 4; ++i) {
ne_perm[permute[i]] = ne[i];
}
ggml_tensor * t = ggml_new_tensor_4d(ctx, type, ne_perm[0], ne_perm[1], ne_perm[2], ne_perm[3]);
if (permute != std::array<int32_t, 4>{0, 1, 2, 3}) {
t = ggml_permute(ctx, t, permute[0], permute[1], permute[2], permute[3]);
}
return t;
};

ggml_tensor * q = create_permuted(GGML_TYPE_F32, hs_padded, nb, nh, 1);
ggml_set_name(q, "q");

ggml_tensor * k = ggml_new_tensor_4d(ctx, type_KV, hs_padded, kv, nh, 1);
ggml_tensor * k = create_permuted(type_KV, hs_padded, kv, nh, 1);
ggml_set_name(k, "k");

ggml_tensor * v = ggml_new_tensor_4d(ctx, type_KV, hs_padded, kv, nh, 1);
ggml_tensor * v = create_permuted(type_KV, hs_padded, kv, nh, 1);
ggml_set_name(v, "v");

ggml_tensor * m = nullptr;
Expand Down Expand Up @@ -4167,6 +4182,10 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {
for (int nb : { 1, 3, 32, 35, }) {
for (ggml_type type_KV : {GGML_TYPE_F16, GGML_TYPE_BF16, GGML_TYPE_Q8_0, GGML_TYPE_Q4_0}) {
test_cases.emplace_back(new test_flash_attn_ext(hs, nh, kv, nb, mask, max_bias, logit_softcap, type_KV));
// run fewer test cases permuted
if (mask == true && max_bias == 0.0f && logit_softcap == 0 && kv == 512) {
test_cases.emplace_back(new test_flash_attn_ext(hs, nh, kv, nb, mask, max_bias, logit_softcap, type_KV, {0, 2, 1, 3}));
}
}
}
}
Expand Down

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