diff --git a/tools/server/server-context.cpp b/tools/server/server-context.cpp
index 48724245d7..62eb660d7f 100644
--- a/tools/server/server-context.cpp
+++ b/tools/server/server-context.cpp
@@ -2625,7 +2625,47 @@ private:
         }
     }
 
+    // @ngxson : for debugging only
+    int64_t t_pre_decode  = 0;
+    int64_t t_decode      = 0;
+    int64_t t_post_decode = 0;
+    int64_t n_pre_decode  = 0;
+    int64_t n_decode      = 0;
+    int64_t n_post_decode = 0;
+#define DEBUG_TIMINGS
+#ifdef DEBUG_TIMINGS
+    struct scoped_timer {
+        int64_t & t;
+        int64_t & n;
+        int64_t t_start;
+        scoped_timer(int64_t & t_, int64_t & n_) : t(t_), n(n_) {
+            t_start = ggml_time_us();
+        }
+        ~scoped_timer() {
+            t += ggml_time_us() - t_start;
+            n++;
+        }
+    };
+#else
+    struct scoped_timer {
+        scoped_timer(int64_t &, int64_t &) {}
+        ~scoped_timer() {}
+    };
+#endif
+
     void update_slots() {
+#ifdef DEBUG_TIMINGS
+        static int64_t t_prev = 0;
+        int64_t t_start = ggml_time_us();
+        if (t_start - t_prev > 5 * 1000 * 1000) { // every 5 seconds
+            t_prev = t_start;
+            SRV_INF("n_pre_decode      = %" PRId64 "\n", n_pre_decode);
+            SRV_INF("avg t_pre_decode  = %f ms\n", (double) t_pre_decode / n_pre_decode / 1000.0);
+            SRV_INF("avg t_decode      = %f ms\n", (double) t_decode / n_decode / 1000.0);
+            SRV_INF("avg t_post_decode = %f ms\n", (double) t_post_decode / n_post_decode / 1000.0);
+        }
+#endif
+
         // check if all slots are idle
         {
             bool all_idle = true;
@@ -2651,6 +2691,7 @@ private:
         }
 
         try {
+            scoped_timer t(t_pre_decode, n_pre_decode);
             pre_decode();
             batch.render();
         } catch (const std::exception & e) {
@@ -2664,6 +2705,7 @@ private:
         for (int32_t off = 0; off < batch.size(); off = off_next) {
             const int32_t n_tokens = std::min(n_batch, batch.size() - off);
             try {
+                scoped_timer t(t_decode, n_decode);
                 // TODO @ngxson : maybe handle n_batch == 1 here instead of inside decode()
 
                 batch_view = batch.get_view(off, n_tokens);
@@ -2686,6 +2728,7 @@ private:
             }
 
             try {
+                scoped_timer t(t_post_decode, n_post_decode);
                 post_decode(n_tokens, off, batch_view);
             } catch (const std::exception & e) {
                 SRV_ERR("post_decode() failed: %s\n", e.what());