diff options
| -rw-r--r-- | ggml.c | 99 |
1 files changed, 64 insertions, 35 deletions
@@ -1962,42 +1962,71 @@ static void ggml_vec_dot_q4_0(const int n, float * restrict s, const void * rest // Initialize accumulator with zeros __m256 acc = _mm256_setzero_ps(); - // Main loop - // TODO: figure a way to do this in a portable way - #ifdef __GNUC__ - #pragma GCC unroll 16 - #endif - for (int i = 0; i < nb; ++i) { - // Compute combined scale for the block - const __m256 d = _mm256_mul_ps( _mm256_broadcast_ss( &x[i].d ), _mm256_broadcast_ss( &y[i].d ) ); - - // Load 16 bytes, and unpack 4 bit fields into bytes, making 32 bytes - __m256i bx = bytesFromNibbles( x[i].qs ); - __m256i by = bytesFromNibbles( y[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 ); - bx = _mm256_sub_epi8( bx, off ); - by = _mm256_sub_epi8( by, off ); - - // 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); - const __m256i i32 = _mm256_madd_epi16(ones, dot); + /* Prepare the constants we will need during execution */ + const __m256i lowMask = _mm256_set1_epi8( 0xF ); + const __m256i offset_8 = _mm256_set1_epi16( 8 ); - // Convert int32_t to float - const __m256 p = _mm256_cvtepi32_ps( i32 ); +#define UNROLL_COUNT 8 + // make sure we only unroll multiples of the block count + assert(nb % UNROLL_COUNT == 0); - // Apply the scale, and accumulate - acc = _mm256_fmadd_ps( d, p, acc ); - } + // Main loop + for (int i = 0; i < nb; i+=UNROLL_COUNT) { + + // This loop will be unrolled by the compiler + for (int u=0;u<UNROLL_COUNT;u++) { + /* Compute combined scale for the block */ + const __m256 scale = _mm256_mul_ps( + _mm256_broadcast_ss( &x[i+u].d ), + _mm256_broadcast_ss( &y[i+u].d ) ); + + /* get input from x + Input: 32 Nibbles (16 bytes) at *x[i+u] + Output: 2 vectors with 16 values of type int16_t (x_high_q, x_low_q) */ + + /* Load 16 bytes from memory */ + const __m128i tmp_x = _mm_loadu_si128( ( const __m128i* ) x[i+u].qs); + /* Expand bytes into uint16_t values */ + const __m256i bytes_x = _mm256_cvtepu8_epi16(tmp_x); + /* Unpack values into individual bytes */ + __m256i x_low_q = _mm256_and_si256( lowMask, bytes_x ); + const __m256i pre_shift_x_high_q = _mm256_andnot_si256( lowMask, bytes_x ); + __m256i x_high_q = _mm256_srli_epi16( pre_shift_x_high_q, 4 ); + /* Now we have two vectors with bytes in [ 0 .. 15 ] interval. Offset them into [ -8 .. +7 ] interval. */ + x_high_q = _mm256_sub_epi16( x_high_q, offset_8 ); + x_low_q = _mm256_sub_epi16( x_low_q, offset_8 ); + + /* get input from y + Input: 32 Nibbles (16 bytes) at *y[i+u] + Output: 2 vectors with 16 values of type int16_t (y_high_q, y_low_q) */ + + /* Load 16 bytes from memory */ + const __m128i tmp_y = _mm_loadu_si128( (const __m128i* ) y[i+u].qs); + /* Expand bytes into uint16_t values */ + const __m256i bytes_y = _mm256_cvtepu8_epi16(tmp_y); + /* Unpack values into individual bytes */ + const __m256i pre_shift_y_high_q = _mm256_andnot_si256( lowMask, bytes_y ); + __m256i y_high_q = _mm256_srli_epi16( pre_shift_y_high_q, 4 ); + __m256i y_low_q = _mm256_and_si256( lowMask, bytes_y ); + /* Now we have two vectors with bytes in [ 0 .. 15 ] interval. Offset them into [ -8 .. +7 ] interval. */ + y_high_q = _mm256_sub_epi16( y_high_q, offset_8 ); + y_low_q = _mm256_sub_epi16( y_low_q, offset_8 ); + + /* Compute products of int16_t integers, add pairwise, store as int32_t */ + __m256i xy_high_q = _mm256_madd_epi16( x_high_q, y_high_q ); + __m256i xy_low_q = _mm256_madd_epi16( x_low_q, y_low_q ); + + /* Accumulate the products of int32_t integers -> we now have a vector of 8 int_32t */ + __m256i xy_q = _mm256_add_epi32( xy_high_q, xy_low_q ); + + /* 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( scale, q, acc ); + } + + } // Return horizontal sum of the acc vector __m128 res = _mm256_extractf128_ps( acc, 1 ); @@ -2026,7 +2055,7 @@ static void ggml_vec_dot_q4_0(const int n, float * restrict s, const void * rest bx = _mm_sub_epi8( bx, off ); by = _mm_sub_epi8( by, off ); - // Get absolute values of x vectors + // Get absolute values of x vectors const __m128i ax = _mm_sign_epi8(bx, bx); // Sign the values of the y vectors |