Performance and stability pass (v1.5.9)

- Tighten transport announce rate limit from 5/sec to 2/sec
- Reduce RNS loop frequency from 200Hz to 100Hz
- Throttle LVGL rendering to 30 FPS (was unthrottled)
- Time-box TCP frame loop to 3 frames / 8ms per client
- Add 12ms global TCP budget across all clients
- Replace blocking WiFi announce delay(1500) with deferred non-blocking check
- Rotate persistData() across 3 cycles to spread file I/O
- Reduce LvNodesScreen rebuild frequency (2s → 5s, skip small transient changes)
- Bump version to 1.5.9

src/config/Config.h

@@ -6,8 +6,8 @@
 
 #define RATDECK_VERSION_MAJOR  1
 #define RATDECK_VERSION_MINOR  5
-#define RATDECK_VERSION_PATCH  8
-#define RATDECK_VERSION_STRING "1.5.8"
+#define RATDECK_VERSION_PATCH  9
+#define RATDECK_VERSION_STRING "1.5.9"
 
 // --- Feature Flags ---
 #define HAS_DISPLAY     true
@@ -47,7 +47,7 @@
 #define TCP_CONNECT_TIMEOUT_MS      5000
 
 // --- Announce Flood Defense ---
-#define RATDECK_MAX_ANNOUNCES_PER_SEC 5     // Transport-level rate limit (before Ed25519 verify)
+#define RATDECK_MAX_ANNOUNCES_PER_SEC 2     // Transport-level rate limit (before Ed25519 verify)
 
 // --- Limits ---
 #define RATDECK_MAX_NODES             200   // PSRAM allows more

src/main.cpp

@@ -120,6 +120,11 @@ unsigned long lastHeartbeat = 0;
 constexpr unsigned long HEARTBEAT_INTERVAL_MS = 5000;
 unsigned long loopCycleStart = 0;
 unsigned long maxLoopTime = 0;
+unsigned long lastLvglTime = 0;
+constexpr unsigned long LVGL_INTERVAL_MS = 33;          // ~30 FPS
+constexpr unsigned long TCP_GLOBAL_BUDGET_MS = 12;      // Max cumulative TCP time per loop
+bool wifiDeferredAnnounce = false;
+unsigned long wifiConnectedAt = 0;
 
 // =============================================================================
 // Announce with display name (MessagePack-encoded app_data)
@@ -888,16 +893,20 @@ void loop() {
         }
     }
 
-    // 3. LVGL timer handler — run FIRST after input for responsive UI
-    if (powerMgr.isScreenOn()) {
-        lv_timer_handler();
+    // 3. LVGL timer handler — throttled to ~30 FPS
+    {
+        unsigned long now = millis();
+        if (powerMgr.isScreenOn() && now - lastLvglTime >= LVGL_INTERVAL_MS) {
+            lastLvglTime = now;
+            lv_timer_handler();
+        }
     }
 
-    // 4. Reticulum loop (radio RX via LoRaInterface) — throttle to ~200Hz
+    // 4. Reticulum loop (radio RX via LoRaInterface) — throttle to ~100Hz
     {
         static unsigned long lastRNS = 0;
         unsigned long now = millis();
-        if (now - lastRNS >= 5) {
+        if (now - lastRNS >= 10) {
             lastRNS = now;
             rns.loop();
         }
@@ -932,20 +941,9 @@ void loop() {
 
             // Recreate TCP clients on every WiFi connect (old clients may have stale sockets)
             reloadTCPClients();
-            // Announce over TCP now that it's available — delay to let VPS register the connection
-            bool anyTcpConnected = false;
-            for (auto* tcp : tcpClients) {
-                if (tcp->isConnected()) { anyTcpConnected = true; break; }
-            }
-            if (anyTcpConnected) {
-                delay(1500);  // Let VPS Reticulum register the new interface
-                Serial.println("[TCP] Sending announce over new TCP connection...");
-                RNS::Bytes appData = encodeAnnounceName(userConfig.settings().displayName);
-                rns.announce(appData);
-                lastAutoAnnounce = millis();
-            } else {
-                Serial.println("[TCP] No TCP clients connected, skipping announce");
-            }
+            // Defer announce to let VPS register the connection (non-blocking)
+            wifiDeferredAnnounce = true;
+            wifiConnectedAt = millis();
         } else if (!connected && wifiSTAConnected) {
             wifiSTAConnected = false;
             ui.statusBar().setWiFiActive(false);
@@ -962,11 +960,32 @@ void loop() {
         }
     }
 
-    // 8. WiFi + TCP loops
+    // 7.5. Deferred WiFi announce (non-blocking replacement for delay(1500))
+    if (wifiDeferredAnnounce && millis() - wifiConnectedAt >= 1500) {
+        wifiDeferredAnnounce = false;
+        bool anyTcpConnected = false;
+        for (auto* tcp : tcpClients) {
+            if (tcp->isConnected()) { anyTcpConnected = true; break; }
+        }
+        if (anyTcpConnected) {
+            Serial.println("[TCP] Sending announce over new TCP connection...");
+            RNS::Bytes appData = encodeAnnounceName(userConfig.settings().displayName);
+            rns.announce(appData);
+            lastAutoAnnounce = millis();
+        } else {
+            Serial.println("[TCP] No TCP clients connected, skipping announce");
+        }
+    }
+
+    // 8. WiFi + TCP loops (with global budget)
     if (wifiImpl) wifiImpl->loop();
-    for (auto* tcp : tcpClients) {
-        tcp->loop();
-        yield();
+    {
+        unsigned long tcpBudgetStart = millis();
+        for (auto* tcp : tcpClients) {
+            if (millis() - tcpBudgetStart >= TCP_GLOBAL_BUDGET_MS) break;
+            tcp->loop();
+            yield();
+        }
     }
 
     // 9. BLE loops

src/reticulum/ReticulumManager.cpp

@@ -232,28 +232,38 @@ void ReticulumManager::loop() {
 }
 
 void ReticulumManager::persistData() {
-    RNS::Transport::persist_data();
-    RNS::Identity::persist_data();
-    // Backup routing tables and known destinations to SD
-    if (_sd && _sd->isReady()) {
-        static const char* files[] = {"/destination_table", "/packet_hashlist", "/known_destinations"};
-        for (const char* name : files) {
-            File f = LittleFS.open(name, "r");
-            if (f && f.size() > 0) {
-                size_t sz = f.size();
-                uint8_t* buf = (uint8_t*)malloc(sz);
-                if (buf) {
-                    f.readBytes((char*)buf, sz);
-                    char sdPath[64];
-                    snprintf(sdPath, sizeof(sdPath), "/ratputer/transport%s", name);
-                    _sd->ensureDir("/ratputer/transport");
-                    _sd->writeSimple(sdPath, buf, sz);
-                    free(buf);
+    // Rotate through persist steps to spread file I/O across cycles
+    switch (_persistCycle) {
+        case 0:
+            RNS::Transport::persist_data();
+            break;
+        case 1:
+            RNS::Identity::persist_data();
+            break;
+        case 2:
+            // Backup routing tables and known destinations to SD
+            if (_sd && _sd->isReady()) {
+                static const char* files[] = {"/destination_table", "/packet_hashlist", "/known_destinations"};
+                for (const char* name : files) {
+                    File f = LittleFS.open(name, "r");
+                    if (f && f.size() > 0) {
+                        size_t sz = f.size();
+                        uint8_t* buf = (uint8_t*)malloc(sz);
+                        if (buf) {
+                            f.readBytes((char*)buf, sz);
+                            char sdPath[64];
+                            snprintf(sdPath, sizeof(sdPath), "/ratputer/transport%s", name);
+                            _sd->ensureDir("/ratputer/transport");
+                            _sd->writeSimple(sdPath, buf, sz);
+                            free(buf);
+                        }
+                    }
+                    if (f) f.close();
                 }
             }
-            if (f) f.close();
-        }
+            break;
     }
+    _persistCycle = (_persistCycle + 1) % 3;
 }
 
 String ReticulumManager::identityHash() const {

src/reticulum/ReticulumManager.h

@@ -73,4 +73,5 @@ private:
     bool _transportActive = false;
     unsigned long _lastPersist = 0;
     unsigned long _lastAnnounceTime = 0;
+    uint8_t _persistCycle = 0;  // Rotating: 0=Transport, 1=Identity, 2=SD backup
 };

src/transport/TCPClientInterface.cpp

@@ -71,9 +71,9 @@ void TCPClientInterface::loop() {
         return;  // Will reconnect on next loop iteration
     }
 
-    // Drain multiple incoming frames per loop (up to 10, time-boxed)
+    // Drain multiple incoming frames per loop (up to 3, time-boxed)
     unsigned long tcpStart = millis();
-    for (int i = 0; i < 10 && _client.available() && (millis() - tcpStart < TCP_LOOP_BUDGET_MS); i++) {
+    for (int i = 0; i < 3 && _client.available() && (millis() - tcpStart < TCP_LOOP_BUDGET_MS); i++) {
         unsigned long rxStart = millis();
         int len = readFrame();
         if (len > 0) {

src/transport/TCPClientInterface.h

@@ -45,7 +45,7 @@ private:
     static constexpr uint8_t FRAME_ESC   = 0x7D;
     static constexpr uint8_t FRAME_XOR   = 0x20;
     static constexpr unsigned long TCP_KEEPALIVE_TIMEOUT_MS = 300000; // 5 min
-    static constexpr unsigned long TCP_LOOP_BUDGET_MS = 15;
+    static constexpr unsigned long TCP_LOOP_BUDGET_MS = 8;
 
 public:
     unsigned long lastRxTime() const { return _lastRxTime; }

src/ui/screens/LvNodesScreen.cpp

@@ -50,9 +50,15 @@ void LvNodesScreen::refreshUI() {
     if (now - _lastRebuild < REBUILD_INTERVAL_MS) return;
     int contacts = 0;
     for (const auto& n : _am->nodes()) { if (n.saved) contacts++; }
-    if (_am->nodeCount() != _lastNodeCount || contacts != _lastContactCount) {
+    int countDelta = abs(_am->nodeCount() - _lastNodeCount);
+    int contactDelta = abs(contacts - _lastContactCount);
+    if (countDelta > 0 || contactDelta > 0) {
         _lastRebuild = now;
-        rebuildList();
+        // Skip rebuild for tiny transient count changes (≤3 nodes, no contact changes)
+        // They'll be picked up on the next interval
+        if (countDelta > 3 || contactDelta > 0) {
+            rebuildList();
+        }
     }
 }
 

src/ui/screens/LvNodesScreen.h

@@ -44,7 +44,7 @@ private:
     std::vector<int> _rowToNodeIdx; // Maps row index -> node index in _am->nodes(), -1 for headers
 
     unsigned long _lastRebuild = 0;
-    static constexpr unsigned long REBUILD_INTERVAL_MS = 2000;
+    static constexpr unsigned long REBUILD_INTERVAL_MS = 5000;
 
     lv_obj_t* _list = nullptr;
     lv_obj_t* _lblEmpty = nullptr;