aditya/llama.cpp
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A better packNibbles and mul_sum_i8_pairs_float implementation using AVX512 (#1119)

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Yishuo Wang 2023-04-23 15:57:05 +08:00 committed by GitHub
parent 0e018fe008
commit c9e2c26f41
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@ -509,14 +509,25 @@ static inline __m256 mul_sum_i8_pairs_float(const __m256i x, const __m256i y) {
const __m256i ax = _mm256_sign_epi8(x, x);
// Sign the values of the y vectors
const __m256i sy = _mm256_sign_epi8(y, x);
#if __AVXVNNI__
const __m256i zero = _mm256_setzero_si256();
const __m256i summed_pairs = _mm256_dpbusd_epi32(zero, ax, sy);
return _mm256_cvtepi32_ps(summed_pairs);
#else
// Perform multiplication and create 16-bit values
const __m256i dot = _mm256_maddubs_epi16(ax, sy);
return sum_i16_pairs_float(dot);
#endif
}
static inline __m128i packNibbles( __m256i bytes )
{
// Move bits within 16-bit lanes from 0000_abcd_0000_efgh into 0000_0000_abcd_efgh
#if __AVX512F__
const __m256i bytes_srli_4 = _mm256_srli_epi16(bytes, 4); // 0000_0000_abcd_0000
bytes = _mm256_or_si256(bytes, bytes_srli_4); // 0000_abcd_abcd_efgh
return _mm256_cvtepi16_epi8(bytes); // abcd_efgh
#else
const __m256i lowByte = _mm256_set1_epi16( 0xFF );
__m256i high = _mm256_andnot_si256( lowByte, bytes );
__m256i low = _mm256_and_si256( lowByte, bytes );
@ -527,6 +538,7 @@ static inline __m128i packNibbles( __m256i bytes )
__m128i r0 = _mm256_castsi256_si128( bytes );
__m128i r1 = _mm256_extracti128_si256( bytes, 1 );
return _mm_packus_epi16( r0, r1 );
#endif
}
#else
static inline __m128i packNibbles( __m128i bytes1, __m128i bytes2 )