Re: cyclictest problem/bug as non-root

[Clark Williams <williams@redhat.com>]

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On Fri, 10 Feb 2012 12:57:21 +0100
Nicholas Mc Guire <der.herr@hofr.at> wrote:

> 
> HI !
> 
>  minor bug in cyclictest but potential causing confusion on cyclictest 
>  resuults when running as non-root user.
> 
> Setup:
>  if one sets the rtprio in /etc/security/limits.conf to something below
>  prio max - like:
> 
>  @hofrat          hard    rtprio          10
>  @hofrat          soft    rtprio          10
> 
>  but then starts cylictest with -p 80 cyclictest will not fuss and also
>  display priority 80 (as it uses par->prio in print_stat) but effectively 
>  runs with prio 0 as the return value of sched_setscheduler is not being
>  checked in timerthread), resulting in semingly bad scheduling jitter values.
> 
>  So maybe cyclictest should take the effective maximum schduling priority
>  of the user and not the scheduling policy maximum. Not sur if the check
>  in timerthread is actually really needed - but it should not hurt ither.
>  patch below (against current git) at "works for me" quality.
> 
> thx!
> hofrat
> 
> 

Thanks Nicholas, I'll apply it and run it through some tests. Looks
good at first glance though.

Clark

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