diff --git a/awesome.c b/awesome.c
index 75e1b9956..3cef91e1c 100644
--- a/awesome.c
+++ b/awesome.c
@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <signal.h>
+#include <sys/time.h>
 
 #include <xcb/bigreq.h>
 #include <xcb/randr.h>
@@ -57,6 +58,12 @@ awesome_t globalconf;
 /** argv used to run awesome */
 static char *awesome_argv;
 
+/** time of last main loop wakeup */
+static struct timeval last_wakeup;
+
+/** current limit for the main loop's runtime */
+static float main_loop_iteration_limit = 0.1;
+
 /** Call before exiting.
  */
 void
@@ -217,9 +224,27 @@ static gint
 a_glib_poll(GPollFD *ufds, guint nfsd, gint timeout)
 {
     guint res;
+    struct timeval now, length_time;
+    float length;
+
+    /* Do all deferred work now */
     awesome_refresh();
+
+    /* Check how long this main loop iteration took */
+    gettimeofday(&now, NULL);
+    timersub(&now, &last_wakeup, &length_time);
+    length = length_time.tv_sec + length_time.tv_usec * 1.0f / 1e6;
+    if (length > main_loop_iteration_limit) {
+        warn("Last main loop iteration took %.6f seconds! Increasing limit for "
+                "this warning to that value.", length);
+        main_loop_iteration_limit = length;
+    }
+
+    /* Actually do the polling, record time of wakeup and check for new xcb events */
     res = g_poll(ufds, nfsd, timeout);
+    gettimeofday(&last_wakeup, NULL);
     a_xcb_check();
+
     return res;
 }
 
@@ -410,9 +435,6 @@ main(int argc, char **argv)
     if (xcb_cursor_context_new(globalconf.connection, globalconf.screen, &globalconf.cursor_ctx) < 0)
         fatal("Failed to initialize xcb-cursor");
 
-    /* Setup the main context */
-    g_main_context_set_poll_func(g_main_context_default(), &a_glib_poll);
-
     /* initialize dbus */
     a_dbus_init();
 
@@ -517,6 +539,10 @@ main(int argc, char **argv)
 
     xcb_flush(globalconf.connection);
 
+    /* Setup the main context */
+    g_main_context_set_poll_func(g_main_context_default(), &a_glib_poll);
+    gettimeofday(&last_wakeup, NULL);
+
     /* main event loop */
     globalconf.loop = g_main_loop_new(NULL, FALSE);
     g_main_loop_run(globalconf.loop);