From Andreas Jacobs <andjac@kawo1.rwth-aachen.de>: bugfix for scheduler

After each iteration of the scheduler's main loop the scheduler
calculates, how much time this iteration took, and then sleeps for
the rest of the scheduler interval. The bug lies in the calculation
of the elapsed time, which is converted from a tick count to a
'struct timeval' which consists of a seconds value and a microseconds
value. The seconds are filled in correctly, but the microseconds
field is filled a milliseconds value instead of a microseconds value.
Consequently the elapsed time is always underestimated and afterwards
the scheduler sleeps too long.

diff --git a/src/scheduler.c b/src/scheduler.c
index e5bdcfd..8f3d07a 100644 (file)
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -116,6 +116,7 @@ scheduler(void)
        * Used to calculate sleep time
        */
       clock_t end_of_loop;
+      clock_t milliseconds_used;
       struct timeval time_used;
       struct event_entry *entry;
       struct timeout_entry *time_out_entry;
@@ -188,8 +189,9 @@ scheduler(void)
       end_of_loop = times(&tms_buf);
 
       //printf("Tick diff: %d\n", end_of_loop - now_times);
-      time_used.tv_sec = ((end_of_loop - now_times) * olsr_cnf->system_tick_divider) / 1000;
-      time_used.tv_usec = ((end_of_loop - now_times) * olsr_cnf->system_tick_divider) % 1000;
+      milliseconds_used = (end_of_loop - now_times) * olsr_cnf->system_tick_divider;
+      time_used.tv_sec = milliseconds_used / 1000;
+      time_used.tv_usec = (milliseconds_used % 1000) * 1000;
 
       //printf("Time used: %d.%04d\n", time_used.tv_sec, time_used.tv_usec);