Better CPU FA performance for DeepSeek-Lite (#410)

* Better CPU FA performance for DeepSeek-Lite

* It must be like this

---------

Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>

Author: ikawrakow

ggml/src/iqk/iqk_mul_mat.cpp

@@ -17242,7 +17242,7 @@ struct FlashAttn {
             q_size = GGML_PAD(q_size, 64);
             if (q_size > kMaxOnStackSize) {
                 auto qptr = get_q_storage(q_size);
-                if (nq1 >= 8) {
+                if (false && nq1 >= 8) {
                     if constexpr (std::is_same_v<KHelper, HelperQ80<Dk, k_step>>) {
 #if FA_TIMING
                         auto t1 = Perf::cur_time();
@@ -17929,6 +17929,12 @@ inline void iqk_deepseek_helper(KHelper& kh, VHelper& vh,
         if (M && S) { M += n; S += n; }
         return false;
     };
+    if (nq1 >= 16) {
+        int n_step = nq1/16;
+        FlashAttn<576, 512, 16, step_k> fa(scale, softcap);
+        fa.compute(kh, vh, 16*n_step, nk1, stride_q, stride_m, stride_qkv, q, mask, qkv, M, S);
+        if (update(16*n_step)) return;
+    }
     if (nq1 >= 8) {
         int n_step = nq1/8;
         FlashAttn<576, 512, 8, step_k> fa(scale, softcap);