diff --git a/client/lib/state/connection_provider.dart b/client/lib/state/connection_provider.dart
index da31aa8..9b758e8 100644
--- a/client/lib/state/connection_provider.dart
+++ b/client/lib/state/connection_provider.dart
@@ -87,6 +87,7 @@ class ConnectionController extends StateNotifier<ConnectionState> {
   Timer? _elapsed;
   Timer? _watchdog;
   bool _probing = false;
+  int _statsTick = 0; // 仅诊断:_onStats 限频打日志
   // 本次 off 的提示语(节点异常/自动切换);kernel off 与显式断开都读它,避免被互相覆盖。
   // 仅 _connect 开始时清空。用户主动断开则保持 null(无提示)。
   String? _offNotice;
@@ -232,8 +233,16 @@ class ConnectionController extends StateNotifier<ConnectionState> {
     final node = _connectedNode;
     if (node == null || node.uuid.isEmpty) return;
     final ds = e.urltestResults.where((r) => r.delayMs > 0).map((r) => r.delayMs);
-    if (ds.isEmpty) return;
+    if (ds.isEmpty) {
+      // 诊断:urltest 为空(每 ~10 帧打一次,免刷屏)。
+      if (_statsTick++ % 10 == 0) {
+        logLine('Latency',
+            'urltest empty: rawResults=${e.urltestResults.length} node=${node.code} nodePing=${node.ping}');
+      }
+      return;
+    }
     final best = ds.reduce((a, b) => a < b ? a : b);
+    if (_statsTick++ % 10 == 0) logLine('Latency', 'urltest best=${best}ms → setLivePing ${node.code}');
     _ref.read(nodesProvider.notifier).setLivePing(node.uuid, best);
   }