[SYCL] Fix DMMV dequantization (ggerganov#9279)

Fixed dmmv dequant for ncols== GGML_SYCL_DMMV_X
arthw · Nov 15, 2024 · c6e616b · c6e616b
1 parent d21f426
commit c6e616b
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/ggml/src/ggml-sycl/dmmv.cpp b/ggml/src/ggml-sycl/dmmv.cpp
@@ -78,8 +78,8 @@ static void dequantize_mul_mat_vec(const void * __restrict__ vx, const dfloat *
     }
 
     // sum up partial sums and write back result
-#pragma unroll
-    for (int mask = warp_size / 2; mask > 0; mask >>= 1) {
+    const int mask_start = ncols > GGML_SYCL_DMMV_X ? WARP_SIZE >> 1 : WARP_SIZE >> 2;
+    for (int mask = mask_start; mask > 0; mask >>= 1) {
         tmp +=
             dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
     }