ggml : update soft max cpu

Author: ggerganov

ggml.c

@@ -10602,7 +10602,7 @@ static void ggml_compute_forward_soft_max_f32(
     const int ir0 = dr*ith;
     const int ir1 = MIN(ir0 + dr, nr);
 
-    float * wdata = (float *) params->wdata + (nc + CACHE_LINE_SIZE_F32) * ith;
+    float * wp = (float *) params->wdata + (nc + CACHE_LINE_SIZE_F32) * ith;
 
     for (int i1 = ir0; i1 < ir1; i1++) {
         float * sp = (float *)((char *) src0->data + i1*src0->nb[1]);
@@ -10611,9 +10611,10 @@ static void ggml_compute_forward_soft_max_f32(
         // broadcast the mask across rows
         float * mp = src1 ? (float *)((char *) src1->data + (i1%ne11)*src1->nb[1]) : NULL;
 
-        float * wp = wdata;
-        for (int i = 0; i < nc; i++) {
-            wp[i] = sp[i]*scale + (mp ? mp[i] : 0.0f);
+        ggml_vec_cpy_f32  (nc, wp, sp);
+        ggml_vec_scale_f32(nc, wp, scale);
+        if (mp) {
+            ggml_vec_acc_f32(nc, wp, mp);
         }
 
 #ifndef NDEBUG
@@ -15939,7 +15940,7 @@ struct ggml_cplan ggml_graph_plan(struct ggml_cgraph * cgraph, int n_threads) {
                 } break;
             case GGML_OP_SOFT_MAX:
                 {
-                    n_tasks = MIN(n_threads, ggml_nrows(node->src[0]));
+                    n_tasks = MIN(MIN(4, n_threads), ggml_nrows(node->src[0]));
 
                     cur = ggml_type_size(GGML_TYPE_F32) * node->ne[0] * n_tasks;
                 } break;