Re: [Xenomai-help] system locks when calling Linux clock_gettime

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 03/13/2012 07:06 PM, Herrera-Bendezu, Luis wrote:
> Hello,
> 
> Xenomai version 2.4.10, Linux version 2.6.30.3, CPU PPC.
> 
> I am trying to work around an issue where the Linux and Xenomai realtime clocks
> drifts when Linux clock is updated by NTP. It was suggested in the mail exchange:
> http://www.mail-archive.com/xenomai@xenomai.org
> 
> to use clock_gettime()/clock_settime() to keep both clocks in sync.
> 
> However, calling linux clock_gettime() from a Xenomai  thread is causing system to
> freeze after a few minutes as shown in the following test program where the interval
> to re-sync clocks is small, 50 msec, to force error faster:

Yes, this is a known issue too. You can only call __real_clock_gettime
when in secondary mode. So, preferably from a thread created with
__real_pthread_create.

Any chance of updating xenomai? Xenomai 2.6 allows accessing a clock
synchronized with Linux clock from xenomai threads, without even
emitting a system call depending on the architecture.

-- 
                                                                Gilles.