From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dragan Noveski Subject: Re: 2.6.23.1-rt9 (and others) Date: Wed, 07 Nov 2007 21:04:10 +0000 Message-ID: <4732284A.6070501@gmx.net> References: <1194413959.8827.66.camel@localhost.localdomain> <473222E2.8030007@gmx.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: linux-rt-users@vger.kernel.org Return-path: Received: from mail.gmx.net ([213.165.64.20]:37355 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753445AbXKGUHf (ORCPT ); Wed, 7 Nov 2007 15:07:35 -0500 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org Steven Rostedt wrote: > On Wed, 7 Nov 2007, Dragan Noveski wrote: > > >> Steven Rostedt wrote: >> >>> Currently, what we do to test RT latencies is to run Thomas Gleixner's >>> cyclictest >>> (http://git.kernel.org/?p=linux/kernel/git/tglx/rt-tests.git;a=summary) >>> as well as hackbench, to see what the maximum latencies we get are. >>> >>> >> hallo, can please someone suggest for how long time you are running >> cyclictest? >> if i run it for about 3 min. i get a feeling that the values will not >> change anymore, so is there any recommended time for how long to run it? >> > > Actually, you want to run it for a long time, and under very heavy load. > I'm currently running it while doing a "make -j128" on a kernel tree. This > takes several hours to complete the make. So far with -rt11 I have a max > latency with one RT thread at the prio of 98 68us. > > When you do run cyclic test, make sure you run it at a higher priority > than the irq threads. And also use the -n option since the default is to > test signals, and that part of the test isn't working so well. > > Here's what I'm running right now: > > ./cyclictest -n -p98 -t1 -i250 > ok, i was trying like './cyclictest -n -t3 -p99' but i ll have a look into -t and -i options more deeper now. but i was running it always for about 3-4 minutes.... > While doing that "make -j120" > > >> another thing i do not know is, if i run cyclictest for lets say 3 >> minutes, than stop ('ctrl+c') and than start again, i get often >> different values. so is it recommended to run it more times and than to >> pick up the best/worst cases. >> >> i have done some tests already with rt7,8 and 10 but i am not sure if >> the tests make any sense - thats why i would really appreciate some >> answers on the both questions. >> >> > > Actually I didn't want to discourage you. For UP, -rt7,8 and 10 really > should be exactly the same (with some noise factures apart). The changes > that were made supposable only affect SMP boxes. But, I'm glad you are > doing the tests, since we also would like to know if anything creeped into > te UP side, and has caused any regressions. > i was expecting this part about 'smp boxes' but anyway, as now i know how to run cyclictest, i will be able to do again and again as the development goes on. > Thanks, for taking the time to test this. > > -- Steve > > i thank you to for this very informative response! cheers, doc