Re: [Xenomai] [PATCH] AT91: SAMA5D3: Adapt Ipipe for AIC5

[Maxime Ripard <maxime.ripard@free-electrons.com>]

On Thu, Jul 17, 2014 at 12:54:10PM +0200, Gilles Chanteperdrix wrote:
> > Which brings an extra question about this. Is the timer
> > calibration supposed to get a minimum latency to 0 (meaning that
> > with a properly calibrated timer, we would only get positive
> > latencies), or that the average latency should be around 0 (which
> > would mean that negative latencies would actually be frequent, but
> > would break the clock_nanosleep documented behaviour).
> > 
> > I'm actually seeing the former, but trying the latter only brings
> > us quite close to having the calibration disabled entirely.
> 
> The calibration is left entirely to the user, so, you choose what is
> best for your application. But indeed, if your application relies on
> clock_nanosleep documented behaviour (should never wake-up early
> except in case of signal), you want to set /proc/xenomai/latency value
> to the minimum value measured by the latency test, minus a safety margin.

Ok, thanks!

I guess you can add my Tested-by tag to your patch, if that makes any
sense for Xenomai.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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