ggml : add ALiBi support for ggml_soft_max_ext (#5488)

* ggml : avoid recomputing alibi slopes (CPU)

* llama : reuse hparams.f_max_alibi_bias in all cases

ggml-ci

* ggml : support alibi bias in ggml_soft_max_ext (CPU + Metal)

ggml-ci

* ggml : handle all SRCs (do not break on first null)

ggml-ci

* tests : do not use slope for large soft_max

accumulates too much error

ggml-ci

* ggml : alternative ALiBi without extra tensor

We compute the slopes in the kernel

ggml-ci

* cuda : add ALiBi support in ggml_soft_max_ext

ggml-ci

* ggml : deprecate ggml_alibi

* ggml : support multi-sequence ALiBi (Metal)

ggml-ci

* cuda : add multi-seq ALiBi + remote F16 soft_max

ggml-ci

* ggml : update deprecation message

* ggml : fix pos ptr when no ALiBi

ggml-ci

* cuda : fix performance (pow -> powf)

* cuda : precompute ALiBi constants

* metal : pre-compute ALiBi slopes

ggml-ci

* llama : init kq_pos only if needed

ggml-ci

* test-backend-ops : add null pos test to soft_max

test-backend-ops : replace soft_max tests

ggml-ci

---------

Co-authored-by: slaren <slarengh@gmail.com>
This commit is contained in:
Georgi Gerganov 2024-02-17 23:04:16 +02:00 committed by GitHub
parent 6e4e973b26
commit 8f1be0d42f
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
9 changed files with 348 additions and 357 deletions

118
ggml.c
View file

@ -5096,16 +5096,28 @@ static struct ggml_tensor * ggml_soft_max_impl(
struct ggml_context * ctx,
struct ggml_tensor * a,
struct ggml_tensor * mask,
struct ggml_tensor * pos,
float scale,
float max_bias,
bool inplace) {
GGML_ASSERT(ggml_is_contiguous(a));
if (mask) {
GGML_ASSERT(ggml_is_contiguous(mask));
GGML_ASSERT(mask->ne[2] == 1);
GGML_ASSERT(mask->ne[3] == 1);
GGML_ASSERT(ggml_is_matrix(mask));
GGML_ASSERT(ggml_can_repeat_rows(mask, a));
}
if (pos) {
GGML_ASSERT(ggml_is_vector(pos));
GGML_ASSERT(pos->type == GGML_TYPE_F32);
GGML_ASSERT(pos->ne[0] == a->ne[0]);
}
if (max_bias > 0.0f) {
GGML_ASSERT(pos);
}
bool is_node = false;
if (a->grad) {
@ -5114,13 +5126,14 @@ static struct ggml_tensor * ggml_soft_max_impl(
struct ggml_tensor * result = inplace ? ggml_view_tensor(ctx, a) : ggml_dup_tensor(ctx, a);
float params[] = { scale };
float params[] = { scale, max_bias };
ggml_set_op_params(result, params, sizeof(params));
result->op = GGML_OP_SOFT_MAX;
result->grad = is_node ? ggml_dup_tensor(ctx, result) : NULL;
result->src[0] = a;
result->src[1] = mask;
result->src[2] = pos;
return result;
}
@ -5128,21 +5141,23 @@ static struct ggml_tensor * ggml_soft_max_impl(
struct ggml_tensor * ggml_soft_max(
struct ggml_context * ctx,
struct ggml_tensor * a) {
return ggml_soft_max_impl(ctx, a, NULL, 1.0f, false);
return ggml_soft_max_impl(ctx, a, NULL, NULL, 1.0f, 0.0f, false);
}
struct ggml_tensor * ggml_soft_max_inplace(
struct ggml_context * ctx,
struct ggml_tensor * a) {
return ggml_soft_max_impl(ctx, a, NULL, 1.0f, true);
return ggml_soft_max_impl(ctx, a, NULL, NULL, 1.0f, 0.0f, true);
}
struct ggml_tensor * ggml_soft_max_ext(
struct ggml_context * ctx,
struct ggml_tensor * a,
struct ggml_tensor * mask,
float scale) {
return ggml_soft_max_impl(ctx, a, mask, scale, false);
struct ggml_tensor * pos,
float scale,
float max_bias) {
return ggml_soft_max_impl(ctx, a, mask, pos, scale, max_bias, false);
}
// ggml_soft_max_back
@ -11495,6 +11510,7 @@ static void ggml_compute_forward_soft_max_f32(
const struct ggml_compute_params * params,
const struct ggml_tensor * src0,
const struct ggml_tensor * src1,
const struct ggml_tensor * src2,
struct ggml_tensor * dst) {
assert(ggml_is_contiguous(dst));
assert(ggml_are_same_shape(src0, dst));
@ -11503,16 +11519,29 @@ static void ggml_compute_forward_soft_max_f32(
return;
}
float scale = 1.0f;
memcpy(&scale, (float *) dst->op_params + 0, sizeof(float));
float scale = 1.0f;
float max_bias = 0.0f;
memcpy(&scale, (float *) dst->op_params + 0, sizeof(float));
memcpy(&max_bias, (float *) dst->op_params + 1, sizeof(float));
// TODO: handle transposed/permuted matrices
const int ith = params->ith;
const int nth = params->nth;
GGML_TENSOR_UNARY_OP_LOCALS
const int64_t ne11 = src1 ? src1->ne[1] : 1;
// TODO: is this supposed to be ceil instead of floor?
// https://huggingface.co/mosaicml/mpt-7b/blob/main/attention.py#L370
const uint32_t n_head_kv = ne02;
const uint32_t n_head_log2 = 1u << (uint32_t) floor(log2(n_head_kv));
const float m0 = powf(2.0f, -(max_bias ) / n_head_log2);
const float m1 = powf(2.0f, -(max_bias / 2.0f) / n_head_log2);
const int nc = src0->ne[0];
const int nr = ggml_nrows(src0);
@ -11525,6 +11554,9 @@ static void ggml_compute_forward_soft_max_f32(
float * wp = (float *) params->wdata + (nc + CACHE_LINE_SIZE_F32) * ith;
// when max_bias <= 0.0f, src2 is not used and we default it to src0 to avoid branching
float * pos = src2 ? (float *) src2->data : src0->data;
for (int i1 = ir0; i1 < ir1; i1++) {
float * sp = (float *)((char *) src0->data + i1*src0->nb[1]);
float * dp = (float *)((char *) dst->data + i1*dst->nb[1]);
@ -11538,6 +11570,16 @@ static void ggml_compute_forward_soft_max_f32(
ggml_vec_acc_f32(nc, wp, mp);
}
// ALiBi bias
if (max_bias > 0.0f) {
const uint32_t h = (i1/ne01)%ne02; // head
const float slope = h < n_head_log2 ? powf(m0, h + 1) : powf(m1, 2*(h - n_head_log2) + 1);
for (int i = 0; i < nc; i++) {
wp[i] = wp[i] + slope*pos[i];
}
}
#ifndef NDEBUG
for (int i = 0; i < nc; ++i) {
//printf("p[%d] = %f\n", i, p[i]);
@ -11582,11 +11624,12 @@ static void ggml_compute_forward_soft_max(
const struct ggml_compute_params * params,
const struct ggml_tensor * src0,
const struct ggml_tensor * src1,
const struct ggml_tensor * src2,
struct ggml_tensor * dst) {
switch (src0->type) {
case GGML_TYPE_F32:
{
ggml_compute_forward_soft_max_f32(params, src0, src1, dst);
ggml_compute_forward_soft_max_f32(params, src0, src1, src2, dst);
} break;
default:
{
@ -11730,22 +11773,20 @@ static void ggml_compute_forward_alibi_f32(
const float m0 = powf(2.0f, -(max_bias) / n_heads_log2_floor);
const float m1 = powf(2.0f, -(max_bias / 2.0f) / n_heads_log2_floor);
for (int64_t i = 0; i < ne0; i++) {
for (int64_t j = 0; j < ne1; j++) {
for (int64_t k = 0; k < ne2_ne3; k++) {
for (int64_t k = 0; k < ne2_ne3; k++) {
// TODO: k*nb2 or k*nb3
float m_k;
if (k < n_heads_log2_floor) {
m_k = powf(m0, k + 1);
} else {
m_k = powf(m1, 2 * (k - n_heads_log2_floor) + 1);
}
for (int64_t i = 0; i < ne0; i++) {
for (int64_t j = 0; j < ne1; j++) {
float * const src = (float *)((char *) src0->data + i*nb0 + j*nb1 + k*nb2);
float * pdst = (float *)((char *) dst->data + i*nb0 + j*nb1 + k*nb2);
// TODO: k*nb2 or k*nb3
float m_k;
if (k < n_heads_log2_floor) {
m_k = powf(m0, k + 1);
} else {
m_k = powf(m1, 2 * (k - n_heads_log2_floor) + 1);
}
pdst[0] = i * m_k + src[0];
}
}
@ -11790,21 +11831,20 @@ static void ggml_compute_forward_alibi_f16(
const float m0 = powf(2.0f, -(max_bias) / n_heads_log2_floor);
const float m1 = powf(2.0f, -(max_bias / 2.0f) / n_heads_log2_floor);
for (int i = 0; i < ne0; i++) {
for (int j = 0; j < ne1; j++) {
for (int k = 0; k < ne2_ne3; k++) {
for (int k = 0; k < ne2_ne3; k++) {
// TODO: k*nb2 or k*nb3
float m_k;
if (k < n_heads_log2_floor) {
m_k = powf(m0, k + 1);
} else {
m_k = powf(m1, 2 * (k - n_heads_log2_floor) + 1);
}
for (int i = 0; i < ne0; i++) {
for (int j = 0; j < ne1; j++) {
ggml_fp16_t * const src = (ggml_fp16_t *)((char *) src0->data + i*nb0 + j*nb1 + k*nb2);
float * pdst = (float *)((char *) dst->data + i*nb0 + j*nb1 + k*nb2);
// TODO: k*nb2 or k*nb3
float m_k;
if (k < n_heads_log2_floor) {
m_k = powf(m0, k + 1);
} else {
m_k = powf(m1, 2 * (k - n_heads_log2_floor) + 1);
}
float * pdst = (float *)((char *) dst->data + i*nb0 + j*nb1 + k*nb2);
// we return F32
pdst[0] = i * m_k + GGML_FP16_TO_FP32(src[0]);
@ -15116,7 +15156,7 @@ static void ggml_compute_forward(struct ggml_compute_params * params, struct ggm
} break;
case GGML_OP_SOFT_MAX:
{
ggml_compute_forward_soft_max(params, tensor->src[0], tensor->src[1], tensor);
ggml_compute_forward_soft_max(params, tensor->src[0], tensor->src[1], tensor->src[2], tensor);
} break;
case GGML_OP_SOFT_MAX_BACK:
{