ggml : do not use BLAS with ggml_mul_mat_id

Author: ggerganov

ggml.c

@@ -9508,8 +9508,11 @@ static bool ggml_compute_forward_mul_mat_use_blas(
     const int64_t ne0 = dst->ne[0];
     const int64_t ne1 = dst->ne[1];
 
+    // NOTE: with GGML_OP_MUL_MAT_ID we don't want to go through the BLAS branch because it will dequantize (to_float)
+    //       all the experts for each batch element and the processing would become incredibly slow
     // TODO: find the optimal values for these
-    if (ggml_is_contiguous(src0) &&
+    if (dst->op != GGML_OP_MUL_MAT_ID &&
+        ggml_is_contiguous(src0) &&
         ggml_is_contiguous(src1) &&
       //src0->type == GGML_TYPE_F32 &&
         src1->type == GGML_TYPE_F32 &&