diff --git a/VKernel/Kernel/services/desktop.vp b/VKernel/Kernel/services/desktop.vp
index f4ae5cc..719da38 100644
--- a/VKernel/Kernel/services/desktop.vp
+++ b/VKernel/Kernel/services/desktop.vp
@@ -1703,6 +1703,11 @@ def desktop_thread(arg: rawptr) -> int:
         _dt_cur_sec: uint32 = timer.timer_get_seconds()
         if _dt_cur_sec != _dt_hb_sec:
             _dt_hb_sec = _dt_cur_sec
+            # [DIAG] 每秒心跳：打印渲染/脏行/窗口/光标关键状态（定位“只刷顶部一小块+卡死”）
+            _dt_dbg: [144]char
+            viperlib.snprintf(&_dt_dbg, 144, "[dt] sec=%u dc=%d dymin=%d dymax=%d rc=%d win=%d cx=%d cy=%d\n",
+                              _dt_cur_sec, _dirty_count, _dirty_y_min, _dirty_y_max, _render_count, _win_count, _cursor_x, _cursor_y)
+            serial.puts(&_dt_dbg)
         cur_sec: uint32 = timer.timer_get_seconds()
         if cur_sec != _last_clock_sec:
             _last_clock_sec = cur_sec