From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 17 Jul 2014 13:59:15 +0200 From: Maxime Ripard Message-ID: <20140717115915.GD20328@lukather> References: <20140707160239.GF13423@lukather> <53BAC5C4.5060704@xenomai.org> <20140708125505.GN13423@lukather> <53BC2AB5.4050801@xenomai.org> <20140710150540.GE27469@lukather> <53BEC794.6090208@xenomai.org> <20140716161801.GA20328@lukather> <53C6D6DA.3060303@xenomai.org> <20140717101807.GC20328@lukather> <53C7AB52.609@xenomai.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <53C7AB52.609@xenomai.org> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] [PATCH] AT91: SAMA5D3: Adapt Ipipe for AIC5 List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: Thomas Petazzoni , Nicolas Ferre , Boris Brezillon , Alexandre Belloni , xenomai@xenomai.org 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 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: