On Jan 19, 2016 3:53 AM, "Sebastian Huber" < sebastian.hu...@embedded-brains.de> wrote: > > The problem is that you set the time via rtems_clock_set() in Init(). The you wait via rtems_task_wake_after(5s in ticks). With a rtems_task_wake_after(n) you wait to the n-th next tick, thus your wait interval is slightly less than 5s in most cases.
That makes sense but it unfortunately makes the obvious explanation of ticker a bit more complicated. :) 0: RTEMS starts 0+t1: clock_set to TIME 0+t[234]: three wake afters 500th clock tick is now exactly five seconds from time 0 but TIME+5 seconds minus t1 clock time. The thing that surprised me was that when I hacked in changes to use rtems_clock_get_tod_timeval(), the times do not indicate that 5 seconds of delay actually occurred. TA1 599562000:1088 TA2 599562000:2143 TA3 599562000:3199 TA1 599562004:997954 TA2 599562009:977896 TA1 599562009:978937 TA3 599562014:957903 TA1 599562014:958944 TA2 599562019:957907 The tasks are delaying 500, 1000, and 1500 ticks with nanoseconds_per_tick = 10000000. Delay operations are guaranteed to be a minimum of the requested amount and this is not being honored. I know this is a duration specified in clock ticks but it is really (ticks * nanoseconds per tick) long in real time. I have not checked delays like sleep() and nanosleep() but tick based ones are 1 tick too short. --joel > On 18/01/16 00:19, Joel Sherrill wrote: >> >> Hi >> >> With the recent clock changes, I am noticing that on some BSPs >> ticker is reporting times 4, 9, 14, ... instead of 5, 10, 15. >> >> It looks like the time is 4.9999999 when it should simply be 5 so >> ticker just reports 4. >> >> Given this is a visible change in behavior, I would like to know >> what causes it and how it can be resolved? >> >> Thanks. >> >> --joel >> >> >> _______________________________________________ >> devel mailing list >> devel@rtems.org >> http://lists.rtems.org/mailman/listinfo/devel > > > -- > Sebastian Huber, embedded brains GmbH > > Address : Dornierstr. 4, D-82178 Puchheim, Germany > Phone : +49 89 189 47 41-16 > Fax : +49 89 189 47 41-09 > E-Mail : sebastian.hu...@embedded-brains.de > PGP : Public key available on request. > > Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG. >
_______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
