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ggml-cpu: optimize avx2 q6_k #22345

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Merged
ggerganov merged 1 commit into from
Apr 26, 2026
Merged

ggml-cpu: optimize avx2 q6_k #22345

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46 changes: 19 additions & 27 deletions ggml/src/ggml-cpu/arch/x86/quants.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2300,9 +2300,8 @@ void ggml_vec_dot_q6_K_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const voi

#if defined __AVX2__

const __m256i m4 = _mm256_set1_epi8(0xF);
const __m256i m2 = _mm256_set1_epi8(3);
const __m256i m32s = _mm256_set1_epi8(32);
const __m256i m3 = _mm256_set1_epi8(3);
const __m256i m15 = _mm256_set1_epi8(15);

__m256 acc = _mm256_setzero_ps();

Expand All @@ -2314,53 +2313,45 @@ void ggml_vec_dot_q6_K_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const voi
const uint8_t * GGML_RESTRICT qh = x[i].qh;
const int8_t * GGML_RESTRICT q8 = y[i].qs;

const __m256i q8sums = _mm256_loadu_si256((const __m256i*)y[i].bsums);
const __m128i scales = _mm_loadu_si128((const __m128i*)x[i].scales);
const __m256i scales_16 = _mm256_cvtepi8_epi16(scales);
const __m256i q8sclsub = _mm256_slli_epi32(_mm256_madd_epi16(q8sums, scales_16), 5);

__m256i sumi = _mm256_setzero_si256();

int is = 0;

for (int j = 0; j < QK_K/128; ++j) {

const __m128i scale_0 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 0));
const __m128i scale_1 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 1));
const __m128i scale_2 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 2));
const __m128i scale_3 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 3));
is += 4;

const __m256i q4bits1 = _mm256_loadu_si256((const __m256i*)q4); q4 += 32;
const __m256i q4bits2 = _mm256_loadu_si256((const __m256i*)q4); q4 += 32;
const __m256i q4bitsH = _mm256_loadu_si256((const __m256i*)qh); qh += 32;

const __m256i q4h_0 = _mm256_slli_epi16(_mm256_and_si256(q4bitsH, m2), 4);
const __m256i q4h_1 = _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bitsH, 2), m2), 4);
const __m256i q4h_2 = _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bitsH, 4), m2), 4);
const __m256i q4h_3 = _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bitsH, 6), m2), 4);
const __m256i q4h_0 = _mm256_slli_epi16(_mm256_and_si256(q4bitsH, m3), 4);
const __m256i q4h_1 = _mm256_slli_epi16(_mm256_and_si256(q4bitsH, _mm256_set1_epi8(12)), 2);
const __m256i q4h_2 = _mm256_and_si256(q4bitsH, _mm256_set1_epi8(48));
const __m256i q4h_3 = _mm256_srli_epi16(_mm256_and_si256(q4bitsH, _mm256_set1_epi8(-64)), 2);

const __m256i q4_0 = _mm256_or_si256(_mm256_and_si256(q4bits1, m4), q4h_0);
const __m256i q4_1 = _mm256_or_si256(_mm256_and_si256(q4bits2, m4), q4h_1);
const __m256i q4_2 = _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits1, 4), m4), q4h_2);
const __m256i q4_3 = _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits2, 4), m4), q4h_3);
const __m256i q4_0 = _mm256_or_si256(_mm256_and_si256(q4bits1, m15), q4h_0);
const __m256i q4_1 = _mm256_or_si256(_mm256_and_si256(q4bits2, m15), q4h_1);
const __m256i q4_2 = _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits1, 4), m15), q4h_2);
const __m256i q4_3 = _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits2, 4), m15), q4h_3);

const __m256i q8_0 = _mm256_loadu_si256((const __m256i*)q8); q8 += 32;
const __m256i q8_1 = _mm256_loadu_si256((const __m256i*)q8); q8 += 32;
const __m256i q8_2 = _mm256_loadu_si256((const __m256i*)q8); q8 += 32;
const __m256i q8_3 = _mm256_loadu_si256((const __m256i*)q8); q8 += 32;

__m256i q8s_0 = _mm256_maddubs_epi16(m32s, q8_0);
__m256i q8s_1 = _mm256_maddubs_epi16(m32s, q8_1);
__m256i q8s_2 = _mm256_maddubs_epi16(m32s, q8_2);
__m256i q8s_3 = _mm256_maddubs_epi16(m32s, q8_3);

__m256i p16_0 = _mm256_maddubs_epi16(q4_0, q8_0);
__m256i p16_1 = _mm256_maddubs_epi16(q4_1, q8_1);
__m256i p16_2 = _mm256_maddubs_epi16(q4_2, q8_2);
__m256i p16_3 = _mm256_maddubs_epi16(q4_3, q8_3);

p16_0 = _mm256_sub_epi16(p16_0, q8s_0);
p16_1 = _mm256_sub_epi16(p16_1, q8s_1);
p16_2 = _mm256_sub_epi16(p16_2, q8s_2);
p16_3 = _mm256_sub_epi16(p16_3, q8s_3);
const __m128i scale_0 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 0));
const __m128i scale_1 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 1));
const __m128i scale_2 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 2));
const __m128i scale_3 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 3));
is += 4;

p16_0 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_0), p16_0);
p16_1 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_1), p16_1);
Expand All @@ -2372,6 +2363,7 @@ void ggml_vec_dot_q6_K_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const voi

}

sumi = _mm256_sub_epi32(sumi, q8sclsub);
acc = _mm256_fmadd_ps(_mm256_broadcast_ss(&d), _mm256_cvtepi32_ps(sumi), acc);
}

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