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SYCL: optimized repeat_back kernel (3× fewer asm instructions, 2× faster)Feature/sycl repeat back opt #16869

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Merged
merged 9 commits into from
Nov 3, 2025
Merged

SYCL: optimized repeat_back kernel (3× fewer asm instructions, 2× faster)Feature/sycl repeat back opt #16869

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8d51e18
SYCL repeat_back v1 — add core op + switch case
shani-f Oct 23, 2025
d3e88bc
Implement repeat_back SYCL operation and minor fixes
shani-f Oct 23, 2025
f7d05e7
SYCL: optimize repeat_back kernel
shani-f Oct 30, 2025
e7149c8
Merge remote-tracking branch 'upstream/master' into feature/sycl-repe…
shani-f Oct 30, 2025
20717ac
Remove Hebrew comment from repeat_back.cpp
shani-f Oct 30, 2025
f2853da
Remove comments for code clarity
shani-f Oct 30, 2025
0efd7eb
Fix formatting in ggml-sycl.cpp
shani-f Oct 31, 2025
2c8f977
Formatted lambda according to legacy style. No logic changes
shani-f Nov 1, 2025
aa20ee1
Remove blank line in repeat_back.cpp
shani-f Nov 1, 2025
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70 changes: 45 additions & 25 deletions ggml/src/ggml-sycl/repeat_back.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,26 +2,43 @@

#include "common.hpp"

void ggml_sycl_op_repeat_back(ggml_backend_sycl_context & ctx, ggml_tensor * dst) {
#define GGML_ASSERT_TENSOR_FITS_INT(t) \
GGML_ASSERT((t)->ne[0] < INT_MAX && (t)->ne[1] < INT_MAX && (t)->ne[2] < INT_MAX && (t)->ne[3] < INT_MAX)

void ggml_sycl_op_repeat_back(ggml_backend_sycl_context & ctx, ggml_tensor * dst) {
GGML_ASSERT(dst->src[0]->type == GGML_TYPE_F32);
GGML_ASSERT(dst->type == GGML_TYPE_F32);

const float * src0_dd = (const float *) dst->src[0]->data;
float * dst_dd = (float *) dst->data;

const int64_t ne0 = dst->ne[0], ne1 = dst->ne[1], ne2 = dst->ne[2], ne3 = dst->ne[3];
const int64_t ne00 = dst->src[0]->ne[0], ne01 = dst->src[0]->ne[1], ne02 = dst->src[0]->ne[2],
ne03 = dst->src[0]->ne[3];
GGML_ASSERT_TENSOR_FITS_INT(dst);
GGML_ASSERT_TENSOR_FITS_INT(dst->src[0]);

const int ne0 = dst->ne[0], ne1 = dst->ne[1], ne2 = dst->ne[2], ne3 = dst->ne[3];
const int ne00 = dst->src[0]->ne[0], ne01 = dst->src[0]->ne[1], ne02 = dst->src[0]->ne[2],
ne03 = dst->src[0]->ne[3];

const int nr0 = ne00 / ne0;
const int nr1 = ne01 / ne1;
const int nr2 = ne02 / ne2;
const int nr3 = ne03 / ne3;

const int nr0 = (int) (ne00 / ne0);
const int nr1 = (int) (ne01 / ne1);
const int nr2 = (int) (ne02 / ne2);
const int nr3 = (int) (ne03 / ne3);
const int nb0 = dst->src[0]->nb[0];
const int nb1 = dst->src[0]->nb[1];
const int nb2 = dst->src[0]->nb[2];
const int nb3 = dst->src[0]->nb[3];

const size_t total = ne0 * ne1 * ne2 * ne3;
const int BLOCK_SIZE = 256;
const int num_blocks = (total + BLOCK_SIZE - 1) / BLOCK_SIZE;
const char * base = (const char *) src0_dd;

const size_t total = (size_t) ne0 * ne1 * ne2 * ne3;
constexpr int BLOCK_SIZE = 256;
const int num_blocks = (total + BLOCK_SIZE - 1) / BLOCK_SIZE;

const float inv_ne0 = 1.0f / ne0;
const float inv_ne_01 = 1.0f / (ne0 * ne1);
const float inv_ne_012 = 1.0f / (ne0 * ne1 * ne2);
const int repeat_count = nr0 * nr1 * nr2 * nr3;

queue_ptr stream = ctx.stream();

Expand All @@ -33,24 +50,27 @@ void ggml_sycl_op_repeat_back(ggml_backend_sycl_context & ctx, ggml_tensor * dst
return;
}

const int i0 = i % ne0;
const int i1 = (i / ne0) % ne1;
const int i2 = (i / (ne0 * ne1)) % ne2;
const int i3 = i / (ne0 * ne1 * ne2);
const int i3 = (int) (i * inv_ne_012);
const int i2 = (int) (i * inv_ne_01) - i3 * ne2;
const int i1 = (int) (i * inv_ne0) - (int) (i * inv_ne_01) * ne1;
const int i0 = i - (int) (i * inv_ne0) * ne0;

int j0 = 0, j1 = 0, j2 = 0, j3 = 0;
float acc = 0.0f;

for (int j3 = 0; j3 < nr3; ++j3) {
for (int j2 = 0; j2 < nr2; ++j2) {
for (int j1 = 0; j1 < nr1; ++j1) {
for (int j0 = 0; j0 < nr0; ++j0) {
acc += src0_dd[(i0 + j0 * ne0) + (i1 + j1 * ne1) * ne00 + (i2 + j2 * ne2) * ne00 * ne01 +
(i3 + j3 * ne3) * ne00 * ne01 * ne02];
}
}
}
}
for (int j = 0; j < repeat_count; ++j) {
const float * ptr = (const float *) (base + (i0 + j0 * ne0) * nb0 + (i1 + j1 * ne1) * nb1 +
(i2 + j2 * ne2) * nb2 + (i3 + j3 * ne3) * nb3);
acc += *ptr;

int carry = (++j0 >= nr0);
j0 -= carry * nr0;
carry = (carry && (++j1 >= nr1));
j1 -= carry * nr1;
carry = (carry && (++j2 >= nr2));
j2 -= carry * nr2;
j3 += carry;
}
dst_dd[i] = acc;
});
}
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