diff --git a/common/utils/T/tracer/gui/Makefile b/common/utils/T/tracer/gui/Makefile
index cc6a409e7512db99e1f8086bfaaff71f0b241fc3..9552d03d82771e3269d63253be7ae4361a07debc 100644
--- a/common/utils/T/tracer/gui/Makefile
+++ b/common/utils/T/tracer/gui/Makefile
@@ -10,6 +10,9 @@ gui.a: $(OBJS)
 test: test.o gui.a
 	$(CC) -o test $(OBJS) test.o -lX11 -pthread -lm
 
+x.o:x.c
+	$(CC) $(CFLAGS) -o $@ -c $< -finstrument-functions
+
 %.o: %.c
 	$(CC) $(CFLAGS) -o $@ -c $<
 
diff --git a/common/utils/T/tracer/gui/gui.c b/common/utils/T/tracer/gui/gui.c
index ef8640b0def445e5cc4d29f13965d981f3bd3dd3..52e1b1cc74cdcdf24c14955bd2a1894e1ffabbc3 100644
--- a/common/utils/T/tracer/gui/gui.c
+++ b/common/utils/T/tracer/gui/gui.c
@@ -5,15 +5,31 @@
 #include <stdlib.h>
 #include <pthread.h>
 
+static volatile int locked = 0;
+
+void __cyg_profile_func_enter (void *func,  void *caller)
+{
+  if (locked == 0) abort();
+  printf("E %p %p %lu\n", func, caller, time(NULL));
+}
+
+void __cyg_profile_func_exit (void *func, void *caller)
+{
+  if (locked == 0) abort();
+  printf("X %p %p %lu\n", func, caller, time(NULL));
+}
+
 void glock(gui *_gui)
 {
   struct gui *g = _gui;
   if (pthread_mutex_lock(g->lock)) ERR("mutex error\n");
+  locked = 1;
 }
 
 void gunlock(gui *_gui)
 {
   struct gui *g = _gui;
+  locked = 0;
   if (pthread_mutex_unlock(g->lock)) ERR("mutex error\n");
 }