From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [ANNOUNCE] kvm-14 release Date: Wed, 21 Feb 2007 09:31:21 -0600 Message-ID: <45DC65C9.6010104@codemonkey.ws> References: <45D98390.6060001@qumranet.com> <45DA25D9.1060509@aurel32.net> <45DA9FFA.2020009@qumranet.com> <45DB7514.3040409@aurel32.net> <45DBFD6E.2060507@qumranet.com> <45DC51E3.7010205@aurel32.net> <45DC54B5.9080608@qumranet.com> <45DC5D4E.5000300@bull.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: kvm-devel , =?ISO-8859-1?Q?S=E9bastien_Dugu=E9?= To: Laurent Vivier Return-path: In-Reply-To: <45DC5D4E.5000300-6ktuUTfB/bM@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Laurent Vivier wrote: > Avi Kivity wrote: > = >> Aurelien Jarno wrote: >> = >>> = >>> = >>>> What is your disk image file format, or are you using a partition? >>>> = >>>> = >>> I am using a raw image file on an ext3 partition. >>> >>> = >>> = >>>> Do the results change (on kvm-14) if you pin the guest to a core with = >>>> 'taskset 1 qemu ...' >>>> = >>>> = >>> Bingo. It now works even faster than kvm-13! >>> >>> real 0m22.307s >>> user 0m13.935s >>> sys 0m4.720 >>> >>> = >>> = >> I'm guessing this is due to the glibc aio implementation, which uses = >> threads instead of true aio. The threads may cause the vcpu to migrate = >> frequently from one code to another. >> >> There are two possible solutions: >> >> - use native aio from http://www.bullopensource.org/posix/. I think = >> the aio signal patches are not yet in, so this may not work. >> - teach the scheduler about the cost of migrating vcpus >> The first approach will solve itself eventually, though slowly if the = >> current slow rate of aio merging continues. We'll have to do the second. >> >> = > > if you prefer the first one, S=E9bastien will release very soon aio patch= es for > 2.6.20 with an up-to-date libposix-aio. > = Hi Laurent, I gave that a shot a little bit ago. Ran into two problems. 1) Couldn't avoid linking to -lrt as QEMU uses time functions from it. 2) While I could get things compiling (with patches), QEMU would SEGV = almost immediately. Could you guys maybe give compiling QEMU w/libposix-aio a shot? I'm = really interested to see if it makes a difference. Regards, Anthony Liguori > [advertising] Keep an eye on the bullopensource website. [/advertising] > :-P > > Regards, > Laurent > = > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share y= our > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3D= DEVDEV > ------------------------------------------------------------------------ > > _______________________________________________ > kvm-devel mailing list > kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/kvm-devel > = ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3DDE= VDEV