ggml-cpu: improve iq2_xs impl for rvv 256b

RehanQasim-dev · taimur-10x · commit bd69a20b36b2 · 2026-03-04T22:09:38.000+05:00
diff --git a/ggml/src/ggml-cpu/arch-fallback.h b/ggml/src/ggml-cpu/arch-fallback.h
@@ -237,7 +237,7 @@
 #define ggml_vec_dot_q2_K_q8_K_generic ggml_vec_dot_q2_K_q8_K
 #define ggml_vec_dot_iq2_xxs_q8_K_generic ggml_vec_dot_iq2_xxs_q8_K
 #define ggml_vec_dot_iq2_xs_q8_K_generic ggml_vec_dot_iq2_xs_q8_K
-#define ggml_vec_dot_iq2_s_q8_K_generic ggml_vec_dot_iq2_s_q8_K
+// #define ggml_vec_dot_iq2_s_q8_K_generic ggml_vec_dot_iq2_s_q8_K
 #define ggml_vec_dot_iq3_xxs_q8_K_generic ggml_vec_dot_iq3_xxs_q8_K
 #define ggml_vec_dot_iq3_s_q8_K_generic ggml_vec_dot_iq3_s_q8_K
 #define ggml_vec_dot_iq1_s_q8_K_generic ggml_vec_dot_iq1_s_q8_K
@@ -285,7 +285,7 @@
 #define ggml_vec_dot_tq1_0_q8_K_generic ggml_vec_dot_tq1_0_q8_K
 #define ggml_vec_dot_tq2_0_q8_K_generic ggml_vec_dot_tq2_0_q8_K
 #define ggml_vec_dot_iq2_xxs_q8_K_generic ggml_vec_dot_iq2_xxs_q8_K
-#define ggml_vec_dot_iq2_xs_q8_K_generic ggml_vec_dot_iq2_xs_q8_K
+// #define ggml_vec_dot_iq2_xs_q8_K_generic ggml_vec_dot_iq2_xs_q8_K
 #define ggml_vec_dot_iq2_s_q8_K_generic ggml_vec_dot_iq2_s_q8_K
 #define ggml_vec_dot_iq3_xxs_q8_K_generic ggml_vec_dot_iq3_xxs_q8_K
 #define ggml_vec_dot_iq3_s_q8_K_generic ggml_vec_dot_iq3_s_q8_K
diff --git a/ggml/src/ggml-cpu/arch/riscv/quants.c b/ggml/src/ggml-cpu/arch/riscv/quants.c
@@ -3800,8 +3800,11 @@ void ggml_vec_dot_iq2_s_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const vo
         case 256:
             ggml_vec_dot_iq2_s_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
+        case 512:
+            ggml_vec_dot_iq2_s_q8_K_vl512(n, s, bs, vx, bx, vy, by, nrc);
+            break;
         default:
-            ggml_vec_dot_iq2_s_q8_K_generic(n, s, bs, vx, bx, vy, by, nrc);
+            ggml_vec_dot_iq2_s_q8_K_vl1024(n, s, bs, vx, bx, vy, by, nrc);
             break;
     }
 #else
@@ -3946,11 +3949,7 @@ static NOINLINE void ggml_vec_dot_iq2_xs_q8_K_vl128(int n, float * GGML_RESTRICT
 
 static NOINLINE void ggml_vec_dot_iq2_xs_q8_K_vl256(int n, float * GGML_RESTRICT s, size_t bs, const void * GGML_RESTRICT vx, size_t bx, const void * GGML_RESTRICT vy, size_t by, int nrc) {
     assert(n % QK_K == 0);
-    assert(nrc == 1);
-    UNUSED(nrc);
-    UNUSED(bx);
-    UNUSED(by);
-    UNUSED(bs);
+    (void)nrc; (void)bx; (void)by; (void)bs;
 
     const block_iq2_xs * GGML_RESTRICT x = vx;
     const block_q8_K   * GGML_RESTRICT y = vy;
@@ -3969,61 +3968,74 @@ static NOINLINE void ggml_vec_dot_iq2_xs_q8_K_vl256(int n, float * GGML_RESTRICT
 
         int32_t sum_int = 0;
 
-        // Loop over 4 subblocks of 64 elements (QK_K = 256)
-        for (int ib64 = 0; ib64 < QK_K / 64; ++ib64) {
-            // Load 8 uint16 indices (controls 64 values)
-            vuint16mf2_t v_qs = __riscv_vle16_v_u16mf2(qs, 8);
-            qs += 8;
+        for (int ib128 = 0; ib128 < 2; ++ib128) {
+
+            vuint16m1_t v_qs = __riscv_vle16_v_u16m1(qs, 16);
+            qs += 16;
 
-            // Extract indices for grid (low 9 bits) and signs (high 7 bits)
-            // Multiply by 8 (<< 3) for byte offsets into the uint64 tables
-            vuint16mf2_t vidx_grid = __riscv_vsll_vx_u16mf2(__riscv_vand_vx_u16mf2(v_qs, 511, 8), 3, 8);
-            vuint16mf2_t vidx_sign = __riscv_vsll_vx_u16mf2(__riscv_vsrl_vx_u16mf2(v_qs, 9, 8), 3, 8);
+            // Prepare offsets for grid and signs
+            vuint16m1_t vidx_grid = __riscv_vsll_vx_u16m1(__riscv_vand_vx_u16m1(v_qs, 511, 16), 3, 16);
+            vuint16m1_t vidx_sign = __riscv_vsll_vx_u16m1(__riscv_vsrl_vx_u16m1(v_qs, 9, 16), 3, 16);
 
-            vuint64m2_t vq2_64 = __riscv_vluxei16_v_u64m2(grid64, vidx_grid, 8);
-            vuint64m2_t vs2_64 = __riscv_vluxei16_v_u64m2(signs64, vidx_sign, 8);
+            // Indexed load 128 weights (16 x 8-byte chunks)
+            vuint64m4_t vq2_64 = __riscv_vluxei16_v_u64m4(grid64, vidx_grid, 16);
+            vuint64m4_t vs2_64 = __riscv_vluxei16_v_u64m4(signs64, vidx_sign, 16);
 
-            vint8m2_t q2u = __riscv_vreinterpret_v_u8m2_i8m2(__riscv_vreinterpret_v_u64m2_u8m2(vq2_64));
-            vint8m2_t q2s = __riscv_vreinterpret_v_u8m2_i8m2(__riscv_vreinterpret_v_u64m2_u8m2(vs2_64));
+            vint8m4_t q2u = __riscv_vreinterpret_v_u8m4_i8m4(__riscv_vreinterpret_v_u64m4_u8m4(vq2_64));
+            vint8m4_t q2s = __riscv_vreinterpret_v_u8m4_i8m4(__riscv_vreinterpret_v_u64m4_u8m4(vs2_64));
 
-            // Apply signs
-            vint8m2_t q2_final = __riscv_vmul_vv_i8m2(q2u, q2s, 64);
+            // Apply signs to get dequantized IQ2 values
+            vint8m4_t q2_final = __riscv_vmul_vv_i8m4(q2u, q2s, 128);
+            asm volatile("" ::: "memory");
 
-            // Load Q8 weights (64 elements)
-            vint8m2_t q8v = __riscv_vle8_v_i8m2(q8, 64);
-            q8 += 64;
+            // Load corresponding Q8 weights
+            vint8m4_t q8v = __riscv_vle8_v_i8m4(q8, 128);
+            q8 += 128;
 
-            // Multiply (Widening to int16, 64 elements -> LMUL=4)
-            vint16m4_t prod = __riscv_vwmul_vv_i16m4(q2_final, q8v, 64);
+            vint16m8_t prod = __riscv_vwmul_vv_i16m8(q2_final, q8v, 128);
+            asm volatile("" ::: "memory");
+
+            uint8_t sc0 = scales[0];
+            uint8_t sc1 = scales[1];
+            uint8_t sc2 = scales[2];
+            uint8_t sc3 = scales[3];
+            scales += 4;
 
-            // Reduction
             vint32m1_t zero_vec = __riscv_vmv_v_x_i32m1(0, 1);
 
-            int32_t sum0 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(
-                           __riscv_vget_v_i16m4_i16m1(prod, 0), zero_vec, 16));
-            int32_t sum1 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(
-                           __riscv_vget_v_i16m4_i16m1(prod, 1), zero_vec, 16));
-            int32_t sum2 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(
-                           __riscv_vget_v_i16m4_i16m1(prod, 2), zero_vec, 16));
-            int32_t sum3 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(
-                           __riscv_vget_v_i16m4_i16m1(prod, 3), zero_vec, 16));
+            // 9. Reduce each 16-element chunk and apply corresponding nibble scale
 
-            // Apply Scales
-            const uint8_t scale_byte_1 = scales[0];
-            const uint8_t scale_byte_2 = scales[1];
-            scales += 2;
+            int32_t s0 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 0), zero_vec, 16));
+            sum_int += s0 * ((sc0 & 0x0F) * 2 + 1);
 
-            sum_int += sum0 * ((scale_byte_1 & 0x0F) * 2 + 1);
-            sum_int += sum1 * ((scale_byte_1 >> 4)   * 2 + 1);
-            sum_int += sum2 * ((scale_byte_2 & 0x0F) * 2 + 1);
-            sum_int += sum3 * ((scale_byte_2 >> 4)   * 2 + 1);
+            int32_t s1 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 1), zero_vec, 16));
+            sum_int += s1 * ((sc0 >> 4) * 2 + 1);
+
+            int32_t s2 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 2), zero_vec, 16));
+            sum_int += s2 * ((sc1 & 0x0F) * 2 + 1);
+
+            int32_t s3 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 3), zero_vec, 16));
+            sum_int += s3 * ((sc1 >> 4) * 2 + 1);
+
+            int32_t s4 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 4), zero_vec, 16));
+            sum_int += s4 * ((sc2 & 0x0F) * 2 + 1);
+
+            int32_t s5 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 5), zero_vec, 16));
+            sum_int += s5 * ((sc2 >> 4) * 2 + 1);
+
+            int32_t s6 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 6), zero_vec, 16));
+            sum_int += s6 * ((sc3 & 0x0F) * 2 + 1);
+
+            int32_t s7 = __riscv_vmv_x_s_i32m1_i32(__riscv_vwredsum_vs_i16m1_i32m1(__riscv_vget_v_i16m8_i16m1(prod, 7), zero_vec, 16));
+            sum_int += s7 * ((sc3 >> 4) * 2 + 1);
         }
 
-        sumf += d * sum_int;
+        sumf += d * (float)sum_int;
     }
     *s = 0.125f * sumf;
 }
 
+
 static void ggml_vec_dot_iq2_xs_q8_K_vl512(int n, float * GGML_RESTRICT s, size_t bs, const void * GGML_RESTRICT vx, size_t bx, const void * GGML_RESTRICT vy, size_t by, int nrc) {
     assert(n % QK_K == 0);
     assert(nrc == 1);
@@ -4099,7 +4111,7 @@ void ggml_vec_dot_iq2_xs_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const v
               ggml_vec_dot_iq2_xs_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
               break;
           default:
-              ggml_vec_dot_iq2_xs_q8_K_generic(n, s, bs, vx, bx, vy, by, nrc);
+              ggml_vec_dot_iq2_xs_q8_K_vl512(n, s, bs, vx, bx, vy, by, nrc);
               break;
       }
 #else
@@ -4371,9 +4383,12 @@ void ggml_vec_dot_iq2_xxs_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const
         case 128:
             ggml_vec_dot_iq2_xxs_q8_K_vl128(n, s, bs, vx, bx, vy, by, nrc);
             break;
-        default:
+        case 256:
             ggml_vec_dot_iq2_xxs_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
+        default:
+            ggml_vec_dot_iq2_xxs_q8_K_vl512(n, s, bs, vx, bx, vy, by, nrc);
+            break;
     }
 #else
     ggml_vec_dot_iq2_xxs_q8_K(n, s, bs, vx, bx, vy, by, nrc);
@@ -4665,13 +4680,13 @@ void ggml_vec_dot_iq3_s_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const vo
 #if defined __riscv_v_intrinsic
     switch (__riscv_vlenb() * 8) {
         case 128:
-             ggml_vec_dot_iq3_s_q8_K_vl128(n, s, bs, vx, bx, vy, by, nrc);
+            ggml_vec_dot_iq3_s_q8_K_vl128(n, s, bs, vx, bx, vy, by, nrc);
             break;
         case 256:
             ggml_vec_dot_iq3_s_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
         default:
-            ggml_vec_dot_iq3_s_q8_K_generic(n, s, bs, vx, bx, vy, by, nrc);
+            ggml_vec_dot_iq3_s_q8_K_vl512(n, s, bs, vx, bx, vy, by, nrc);
             break;
     }
 #else
@@ -5058,8 +5073,11 @@ void ggml_vec_dot_iq3_xxs_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const
         case 256:
             ggml_vec_dot_iq3_xxs_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
+        case 512:
+            ggml_vec_dot_iq3_xxs_q8_K_vl512(n, s, bs, vx, bx, vy, by, nrc);
+            break;
         default:
-            ggml_vec_dot_iq3_xxs_q8_K_generic(n, s, bs, vx, bx, vy, by, nrc);
+            ggml_vec_dot_iq3_xxs_q8_K_vl1024(n, s, bs, vx, bx, vy, by, nrc);
             break;
     }
 #else
@@ -5939,7 +5957,7 @@ void ggml_vec_dot_tq2_0_q8_K(int n, float * GGML_RESTRICT s, size_t bs, const vo
             ggml_vec_dot_tq2_0_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
         default:
-            ggml_vec_dot_tq2_0_q8_K_generic(n, s, bs, vx, bx, vy, by, nrc);
+            ggml_vec_dot_tq2_0_q8_K_vl256(n, s, bs, vx, bx, vy, by, nrc);
             break;
     }
 #else
