Re: [Xenomai-help] Xenomai 2.5.3 vs gettimeofday() --> livelock?

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

On 07/06/2011 10:38 PM, Jeremy Friesner wrote:
> My first question is:  Am I right in suspecting that gettimeofday()
> can occasionally spin/livelock, when called from a Xenomai 2.5.3
> real-time thread?  FWIW, it gets called from the real-time thread
> once every 333mS.

Yes, this is a known issue.

> 
> And if that is the case, my second question is:  Is there an
> alternative "safe" way to call gettimeofday() (or something
> equivalent) so that the real-time thread can find out the current PTP
> system time?  Or do I need to re-write my code so that the real-time
> thread never calls gettimeofday()?
> 
> Is there a recommended practice for using Xenomai threads in
> conjunction with PTP?

There are several ways out:
- the rtdk library provides a version of gettimeofday which switches to
secondary mode before calling the real gettimeofday. In order to use it,
you have to link your application with:
-Wl,--wrap,gettimeofday -lrtdk
- you can forcibly emit the syscall like the clocktest application does.

-- 
                                                                Gilles.