loggerd: don't let a single service clog up the main thread

selfdrive/loggerd/loggerd.cc

@@ -180,6 +180,7 @@ void rotate_if_needed(LoggerdState *s) {
 void loggerd_thread() {
   // setup messaging
   typedef struct QlogState {
+    std::string name;
     int counter, freq;
   } QlogState;
   std::unordered_map<SubSocket*, QlogState> qlog_states;
@@ -195,7 +196,11 @@ void loggerd_thread() {
     SubSocket * sock = SubSocket::create(s.ctx, it.name);
     assert(sock != NULL);
     poller->registerSocket(sock);
-    qlog_states[sock] = {.counter = 0, .freq = it.decimation};
+    qlog_states[sock] = {
+      .name = it.name,
+      .counter = 0,
+      .freq = it.decimation,
+    };
   }
 
   // init logger
@@ -219,6 +224,7 @@ void loggerd_thread() {
     // poll for new messages on all sockets
     for (auto sock : poller->poll(1000)) {
       // drain socket
+      int count = 0;
       QlogState &qs = qlog_states[sock];
       Message *msg = nullptr;
       while (!do_exit && (msg = sock->receive(true))) {
@@ -233,6 +239,12 @@ void loggerd_thread() {
           double seconds = (millis_since_boot() - start_ts) / 1000.0;
           LOGD("%lu messages, %.2f msg/sec, %.2f KB/sec", msg_count, msg_count / seconds, bytes_count * 0.001 / seconds);
         }
+
+        count++;
+        if (count >= 50) {
+          LOGE("large volume of '%s' messages", qs.name.c_str());
+          break;
+        }
       }
     }
   }