From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philippe Gerum In-Reply-To: References: <4BD99F8C.3090800@domain.hid> <1272554724.28983.444.camel@domain.hid> <1272616194.24705.36.camel@domain.hid> <1272619558.24705.40.camel@domain.hid> Content-Type: text/plain; charset="UTF-8" Date: Fri, 30 Apr 2010 14:41:27 +0200 Message-ID: <1272631287.24705.72.camel@domain.hid> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] cyclictest gives out segmentation fault with xenomai 2.5.2 in powerpc arch List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Pan Cc: xenomai@xenomai.org On Fri, 2010-04-30 at 20:03 +0800, Peter Pan wrote: > OK, I got that. > > But which task mode should this latency test be run for? > user-mode task or kernel periodic task? > It depends on your particular use case, since the latency value is global for all modes, but I guess you will likely run userland rt apps, which is recommended, so latency [-t0] is what you look for. Userland latency should be higher than any other modes. > 2010/4/30 Philippe Gerum : > > On Fri, 2010-04-30 at 17:17 +0800, Peter Pan wrote: > >> I set the /proc/xenomai/latency to 0, and get some latency results. > >> How could I set the latency to a proper value? I'm on vocation now. I > >> will post my latency result when I'm back to work. > > > > You should run the /usr/xenomai/bin/latency test when your calibrated > > latency is reset to 0, for a few seconds on your idle platform. In the > > left most column after you stopped the test, you should see the minimum > > latency value, which your reported to be negative. Use abs(min-lat) as > > the next /proc/xenomai/latency value, and redo the test, until you end > > up with a min-lat slightly higher than 0, from a few tenths of > > nanoseconds. > > > >> > >> 2010/4/30 Philippe Gerum : > >> > On Fri, 2010-04-30 at 08:16 +0800, Peter Pan wrote: > >> >> It's an EVM board of PPC460GT. > >> >> > >> >> I think the processor is very powerful, that may make xenomai workable > >> >> on our system. > >> > > >> >> I'll try to reduce the latency to a proper value. > >> > > >> > When you are done, I'd be interested in knowing the proper calibration > >> > value for this platform, so that I can pre-set it in > >> > include/asm-powerpc/calibration.h for future users. > >> > > >> > PS: echo 0 > /proc/xenomai/latency is the way to disable the > >> > anticipation in setting timer shots, so that you can determine the > >> > minimum latency of your platform, i.e. abs(min-lat) from the latency > >> > test output, on an idle system. > >> > > >> > TIA, > >> > > > > > > > -- > > Philippe. > > > > > > -- Philippe.