From c8c2c524827be8fd681a63f0e5a697b0bf4c587b Mon Sep 17 00:00:00 2001 From: Stephan Walter Date: Thu, 20 Apr 2023 06:45:41 +0000 Subject: [PATCH] AVX2 optimization for vec_dot_q4_2_q8_0 (#1068) --- ggml.c | 99 +++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 73 insertions(+), 26 deletions(-) diff --git a/ggml.c b/ggml.c index 9a3430859..35b15cc2e 100644 --- a/ggml.c +++ b/ggml.c @@ -467,12 +467,30 @@ static const size_t CACHE_LINE_SIZE_F32 = CACHE_LINE_SIZE/sizeof(float); // quantization // -// AVX routines provided by GH user Const-me -// ref: https://github.com/ggerganov/ggml/pull/27#issuecomment-1464934600 +#if __AVX__ || __AVX2__ || __AVX512F__ +// Unpack 16 4-bit fields into 16 bytes +// The output vector contains 16 bytes, each one in [ 0 .. 15 ] interval +static inline __m128i bytes_from_nibbles_16(const uint8_t * rsi) +{ + // Load 8 bytes from memory + __m128i tmp = _mm_loadu_si64( ( const __m128i* )rsi ); + + // Expand bytes into uint16_t values + __m128i bytes = _mm_cvtepu8_epi16( tmp ); + + // Unpack values into individual bytes + const __m128i lowMask = _mm_set1_epi8( 0xF ); + __m128i high = _mm_andnot_si128( lowMask, bytes ); + __m128i low = _mm_and_si128( lowMask, bytes ); + high = _mm_slli_epi16( high, 4 ); + bytes = _mm_or_si128( low, high ); + return bytes; +} + #if __AVX2__ || __AVX512F__ // Unpack 32 4-bit fields into 32 bytes // The output vector contains 32 bytes, each one in [ 0 .. 15 ] interval -static inline __m256i bytesFromNibbles( const uint8_t* rsi ) +static inline __m256i bytes_from_nibbles_32(const uint8_t * rsi) { // Load 16 bytes from memory __m128i tmp = _mm_loadu_si128( ( const __m128i* )rsi ); @@ -503,24 +521,7 @@ static inline __m128i packNibbles( __m256i bytes ) __m128i r1 = _mm256_extracti128_si256( bytes, 1 ); return _mm_packus_epi16( r0, r1 ); } -#elif __AVX__ -static inline __m128i bytesFromNibbles( const uint8_t* rsi ) -{ - // Load 8 bytes from memory - __m128i tmp = _mm_loadu_si64( ( const __m128i* )rsi ); - - // Expand bytes into uint16_t values - __m128i bytes = _mm_cvtepu8_epi16( tmp ); - - // Unpack values into individual bytes - const __m128i lowMask = _mm_set1_epi8( 0xF ); - __m128i high = _mm_andnot_si128( lowMask, bytes ); - __m128i low = _mm_and_si128( lowMask, bytes ); - high = _mm_slli_epi16( high, 4 ); - bytes = _mm_or_si128( low, high ); - return bytes; -} - +#else static inline __m128i packNibbles( __m128i bytes1, __m128i bytes2 ) { // Move bits within 16-bit lanes from 0000_abcd_0000_efgh into 0000_0000_abcd_efgh @@ -537,6 +538,7 @@ static inline __m128i packNibbles( __m128i bytes1, __m128i bytes2 ) return _mm_packus_epi16( bytes1, bytes2); } #endif +#endif // __AVX__ || __AVX2__ || __AVX512F__ #if __ARM_NEON @@ -1395,7 +1397,7 @@ static void dequantize_row_q4_0(const void * restrict vx, float * restrict y, in for (int l = 0; l < QK4_0; l += 32) { // Load 32x4-bit integers into 32x8-bit integers - __m256i vx8 = bytesFromNibbles(pp+l/2); + __m256i vx8 = bytes_from_nibbles_32(pp+l/2); // Subtract 8 from the integers vx8 = _mm256_sub_epi8(vx8, _mm256_set1_epi8(8)); @@ -1513,7 +1515,7 @@ static void dequantize_row_q4_1(const void * restrict vx, float * restrict y, in for (int l = 0; l < QK4_1; l += 32) { // Load 32x4-bit integers into 32x8-bit integers - __m256i vx8 = bytesFromNibbles(pp+l/2); + __m256i vx8 = bytes_from_nibbles_32(pp+l/2); // Convert to 16-bit int const __m256i vx16_lo = _mm256_cvtepi8_epi16(_mm256_extracti128_si256(vx8, 0)); @@ -2356,7 +2358,7 @@ static void ggml_vec_dot_q4_0_q8_0(const int n, float * restrict s, const void * /* Compute combined scale for the block */ const __m256 d = _mm256_mul_ps( _mm256_broadcast_ss( &x[i].d ), _mm256_broadcast_ss( &y[i].d ) ); - __m256i bx = bytesFromNibbles(x[i].qs); + __m256i bx = bytes_from_nibbles_32(x[i].qs); // Now we have a vector with bytes in [ 0 .. 15 ] interval. Offset them into [ -8 .. +7 ] interval. const __m256i off = _mm256_set1_epi8( 8 ); @@ -2402,7 +2404,7 @@ static void ggml_vec_dot_q4_0_q8_0(const int n, float * restrict s, const void * __m128i i32[2]; for (int j = 0; j < 2; ++j) { // Load 8 bytes, and unpack 4 bit fields into bytes, making 16 bytes - __m128i bx = bytesFromNibbles( x[i].qs + 8*j ); + __m128i bx = bytes_from_nibbles_16(x[i].qs + 8*j); __m128i by = _mm_loadu_si128((const __m128i *)(y[i].qs + 16*j)); // Now we have a vector with bytes in [ 0 .. 15 ] interval. Offset them into [ -8 .. +7 ] interval. @@ -2567,7 +2569,7 @@ static void ggml_vec_dot_q4_1_q8_0(const int n, float * restrict s, const void * const __m256 d1m0 = _mm256_mul_ps( d1v, m0v ); // Load 16 bytes, and unpack 4 bit fields into bytes, making 32 bytes - const __m256i bx = bytesFromNibbles( x[i].qs ); + const __m256i bx = bytes_from_nibbles_32(x[i].qs); const __m256i by = _mm256_loadu_si256( (const __m256i *)y[i].qs ); // Get absolute values of x vectors @@ -2721,6 +2723,51 @@ static void ggml_vec_dot_q4_2_q8_0(const int n, float * restrict s, const void * } sumf = vaddvq_f32(sumv0) + vaddvq_f32(sumv1); +#elif defined(__AVX2__) + // Initialize accumulator with zeros + __m256 acc = _mm256_setzero_ps(); + + // Main loop + for (int i = 0; i < nb; i++) { + /* Compute combined scale for the block */ + const __m128 d0 = _mm_set1_ps(GGML_FP16_TO_FP32(x[2*i + 0].d)); + const __m128 d1 = _mm_set1_ps(GGML_FP16_TO_FP32(x[2*i + 1].d)); + const __m256 d = _mm256_mul_ps(_mm256_set_m128(d1, d0), _mm256_broadcast_ss(&y[i].d)); + + __m128i bx0 = bytes_from_nibbles_16(x[2*i + 0].qs); + __m128i bx1 = bytes_from_nibbles_16(x[2*i + 1].qs); + __m256i bx = _mm256_set_m128i(bx1, bx0); + + // Now we have a vector with bytes in [ 0 .. 15 ] interval. Offset them into [ -8 .. +7 ] interval. + const __m256i off = _mm256_set1_epi8(8); + bx = _mm256_sub_epi8(bx, off); + + __m256i by = _mm256_loadu_si256((const __m256i *)y[i].qs); + + // Get absolute values of x vectors + const __m256i ax = _mm256_sign_epi8(bx, bx); + // Sign the values of the y vectors + const __m256i sy = _mm256_sign_epi8(by, bx); + // Perform multiplication and create 16-bit values + const __m256i dot = _mm256_maddubs_epi16(ax, sy); + + const __m256i ones = _mm256_set1_epi16(1); + __m256i xy_q = _mm256_madd_epi16(ones, dot); + + /* Convert to vectore of 8 int32_t to 8 floats */ + __m256 q = _mm256_cvtepi32_ps(xy_q); + + /* Multiply q with scale and accumulate */ + acc = _mm256_fmadd_ps(d, q, acc); + } + + // Return horizontal sum of the acc vector + __m128 res = _mm256_extractf128_ps(acc, 1); + res = _mm_add_ps(res, _mm256_castps256_ps128(acc)); + res = _mm_add_ps(res, _mm_movehl_ps(res, res)); + res = _mm_add_ss(res, _mm_movehdup_ps(res)); + + sumf = _mm_cvtss_f32(res); #else // scalar for (int i = 0; i < nb; i++) {