From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4FF1602A.5040909@xenomai.org> Date: Mon, 02 Jul 2012 10:47:38 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4FEED882.9070307@xenomai.org> <4FEF2EB1.3050600@logilin.fr> <4FEF31AC.2000403@xenomai.org> <4FF09E30.5050400@logilin.fr> <4FF0A625.7070408@xenomai.org> <4FF13B93.1040302@logilin.fr> <4FF1497F.8080909@logilin.fr> In-Reply-To: <4FF1497F.8080909@logilin.fr> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] question: XENO_OPT_TIMING_SCHEDLAT List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christophe Blaess Cc: xenomai@xenomai.org On 07/02/2012 09:11 AM, Christophe Blaess wrote: > On 02/07/2012 08:12, Christophe Blaess wrote: >> >> But, there's still something weird (I run on a stock xenomai 2.6.0 >> with adeos-ipipe-2.6.38.8-arm-1.18-04.patch, I'll try on a 2.6 git >> kernel) >> >> [Panda]#*echo 2388 > /proc/xenomai/latency* >> [Panda]#*cat /proc/xenomai/latency* >> 2386 >> [Panda]#*echo 2386 > /proc/xenomai/latency* >> [Panda]#*cat /proc/xenomai/latency* >> 2384 >> [Panda]#*echo 2384 > /proc/xenomai/latency* >> [Panda]#*cat /proc/xenomai/latency* >> 2382 >> [Panda]# >> >> I suspect something wrong in xnarch_tsc_to_ns()/xnarch_ns_to_tsc() >> maybe in xnarch_llimd(). I'll investigate more this afternoon. >> >> > > I see the same behaviour with xenomai 2.6 from git source, using > adeos-ipipe-2.6.38.8-arm-1.18-08.patch This is because xnarch_tsc_to_ns and xnarch_ns_to_tsc both round toward 0, and the tsc frequency is not a round number of ticks. I do not think trying to fix an issue for a difference of 2ns is worth the trouble. -- Gilles.