diff --git a/src/timer_gettimeofday.c b/src/timer_gettimeofday.c
index 1bf714e..4298805 100644
--- a/src/timer_gettimeofday.c
+++ b/src/timer_gettimeofday.c
@@ -33,7 +33,13 @@
 
 /*! shim around gettimeofday to be able to set the time manually.
  * To override, set osmo_gettimeofday_override == true and set the desired
- * current time in osmo_gettimeofday_override_time. */
+ * current time in osmo_gettimeofday_override_time.
+ *
+ * N. B: gettimeofday() is affected by discontinuous jumps in the system time
+ *       (e.g., if the system administrator manually changes the system time).
+ *       Hence this should NEVER be used for elapsed time computation.
+ *       Instead, clock_gettime(CLOCK_MONOTONIC, ..) should be used for that (with similar shim if necessary).
+ */
 int osmo_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	if (osmo_gettimeofday_override) {