AVX version of the q6k vec-dot. (#493)

* AVX version of the q6k vec-dot.

* Use the avx sum.

candle-core/src/quantized/avx.rs

@@ -1,4 +1,4 @@
-use super::k_quants::{BlockQ4_0, BlockQ8_0, QK8_0};
+use super::k_quants::{BlockQ4_0, BlockQ6K, BlockQ8K, BlockQ8_0, QK8_0, QK_K};
 use crate::Result;
 use half::f16;
 
@@ -70,3 +70,102 @@ pub(crate) fn vec_dot_q4_0_q8_0(n: usize, xs: &[BlockQ4_0], ys: &[BlockQ8_0]) ->
         Ok(hsum_float_8(acc))
     }
 }
+
+const K_SHUFFLE: [u8; 128] = [
+    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+    4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7,
+    8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11,
+    11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14,
+    14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15,
+];
+
+unsafe fn get_scale_shuffle(i: usize) -> __m128i {
+    _mm_loadu_si128((K_SHUFFLE.as_ptr() as *const __m128i).add(i))
+}
+#[inline(always)]
+pub(crate) fn vec_dot_q6k_q8k(n: usize, xs: &[BlockQ6K], ys: &[BlockQ8K]) -> Result<f32> {
+    let qk = QK_K;
+    if n % qk != 0 {
+        crate::bail!("vec_dot_q6k_8k: {n} is not divisible by {qk}")
+    }
+
+    unsafe {
+        let m4 = _mm256_set1_epi8(0xF);
+        let m2 = _mm256_set1_epi8(3);
+        let m32s = _mm256_set1_epi8(32);
+        let mut acc = _mm256_setzero_ps();
+        for (x, y) in xs.iter().zip(ys.iter()) {
+            let d = y.d * x.d.to_f32();
+            let mut q4 = x.ql.as_ptr();
+            let mut qh = x.qh.as_ptr();
+            let mut q8 = y.qs.as_ptr();
+
+            let scales = _mm_loadu_si128(x.scales.as_ptr() as *const __m128i);
+            let mut sumi = _mm256_setzero_si256();
+
+            for j in 0..QK_K / 128 {
+                let is = j * 4;
+                let scale_0 = _mm_shuffle_epi8(scales, get_scale_shuffle(is));
+                let scale_1 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 1));
+                let scale_2 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 2));
+                let scale_3 = _mm_shuffle_epi8(scales, get_scale_shuffle(is + 3));
+
+                let q4bits1 = _mm256_loadu_si256(q4 as *const __m256i);
+                q4 = q4.add(32);
+                let q4bits2 = _mm256_loadu_si256(q4 as *const __m256i);
+                q4 = q4.add(32);
+                let q4bits_h = _mm256_loadu_si256(qh as *const __m256i);
+                qh = qh.add(32);
+
+                let q4h_0 = _mm256_slli_epi16(_mm256_and_si256(q4bits_h, m2), 4);
+                let q4h_1 =
+                    _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bits_h, 2), m2), 4);
+                let q4h_2 =
+                    _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bits_h, 4), m2), 4);
+                let q4h_3 =
+                    _mm256_slli_epi16(_mm256_and_si256(_mm256_srli_epi16(q4bits_h, 6), m2), 4);
+
+                let q4_0 = _mm256_or_si256(_mm256_and_si256(q4bits1, m4), q4h_0);
+                let q4_1 = _mm256_or_si256(_mm256_and_si256(q4bits2, m4), q4h_1);
+                let q4_2 =
+                    _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits1, 4), m4), q4h_2);
+                let q4_3 =
+                    _mm256_or_si256(_mm256_and_si256(_mm256_srli_epi16(q4bits2, 4), m4), q4h_3);
+
+                let q8_0 = _mm256_loadu_si256(q8 as *const __m256i);
+                q8 = q8.add(32);
+                let q8_1 = _mm256_loadu_si256(q8 as *const __m256i);
+                q8 = q8.add(32);
+                let q8_2 = _mm256_loadu_si256(q8 as *const __m256i);
+                q8 = q8.add(32);
+                let q8_3 = _mm256_loadu_si256(q8 as *const __m256i);
+                q8 = q8.add(32);
+
+                let q8s_0 = _mm256_maddubs_epi16(m32s, q8_0);
+                let q8s_1 = _mm256_maddubs_epi16(m32s, q8_1);
+                let q8s_2 = _mm256_maddubs_epi16(m32s, q8_2);
+                let q8s_3 = _mm256_maddubs_epi16(m32s, q8_3);
+
+                let p16_0 = _mm256_maddubs_epi16(q4_0, q8_0);
+                let p16_1 = _mm256_maddubs_epi16(q4_1, q8_1);
+                let p16_2 = _mm256_maddubs_epi16(q4_2, q8_2);
+                let p16_3 = _mm256_maddubs_epi16(q4_3, q8_3);
+
+                let p16_0 = _mm256_sub_epi16(p16_0, q8s_0);
+                let p16_1 = _mm256_sub_epi16(p16_1, q8s_1);
+                let p16_2 = _mm256_sub_epi16(p16_2, q8s_2);
+                let p16_3 = _mm256_sub_epi16(p16_3, q8s_3);
+
+                let p16_0 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_0), p16_0);
+                let p16_1 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_1), p16_1);
+                let p16_2 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_2), p16_2);
+                let p16_3 = _mm256_madd_epi16(_mm256_cvtepi8_epi16(scale_3), p16_3);
+
+                sumi = _mm256_add_epi32(sumi, _mm256_add_epi32(p16_0, p16_1));
+                sumi = _mm256_add_epi32(sumi, _mm256_add_epi32(p16_2, p16_3));
+            }
+            acc = _mm256_fmadd_ps(_mm256_broadcast_ss(&d), _mm256_cvtepi32_ps(sumi), acc);
+        }
+        Ok(hsum_float_8(acc))
+    }
+}

candle-core/src/quantized/k_quants.rs

@@ -462,7 +462,11 @@ impl GgmlType for BlockQ6K {
     const BLCK_SIZE: usize = QK_K;
     type VecDotType = BlockQ8K;
 
+    #[allow(unreachable_code)]
     fn vec_dot(n: usize, xs: &[Self], ys: &[Self::VecDotType]) -> Result<f32> {
+        #[cfg(target_feature = "avx")]
+        return super::avx::vec_dot_q6k_q8k(n, xs, ys);
+
         if n % QK_K != 0 {
             crate::bail!("vec_dot_q6k_q8k: {n} is not divisible by {QK_K}")
         }