From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Vivier Subject: Re: [ANNOUNCE] kvm-14 release Date: Wed, 21 Feb 2007 17:07:58 +0100 Message-ID: <45DC6E5E.2040700@bull.net> 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> <45DC65C9.6010104@codemonkey.ws> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0414592886==" Cc: kvm-devel , =?ISO-8859-1?Q?S=E9basti?= =?ISO-8859-1?Q?en_Dugu=E9?= To: Anthony Liguori Return-path: In-Reply-To: <45DC65C9.6010104-rdkfGonbjUSkNkDKm+mE6A@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 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============0414592886== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig9B6FB46A051104007754F32A" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig9B6FB46A051104007754F32A Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Anthony Liguori wrote: > Laurent Vivier wrote: >> Avi Kivity wrote: >> =20 >>> Aurelien Jarno wrote: >>> =20 >>>> =20 >>>> =20 >>>>> What is your disk image file format, or are you using a partition? >>>>> =20 >>>>> =20 >>>> I am using a raw image file on an ext3 partition. >>>> >>>> =20 >>>> =20 >>>>> Do the results change (on kvm-14) if you pin the guest to a core wi= th=20 >>>>> 'taskset 1 qemu ...' >>>>> =20 >>>>> =20 >>>> Bingo. It now works even faster than kvm-13! >>>> >>>> real 0m22.307s >>>> user 0m13.935s >>>> sys 0m4.720 >>>> >>>> =20 >>>> =20 >>> 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 migra= te=20 >>> frequently from one code to another. >>> >>> There are two possible solutions: >>> >>> - use native aio from http://www.bullopensource.org/posix/. I think= =20 >>> 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= =20 >>> current slow rate of aio merging continues. We'll have to do the sec= ond. >>> >>> =20 >> if you prefer the first one, S=E9bastien will release very soon aio pa= tches for >> 2.6.20 with an up-to-date libposix-aio. >> =20 >=20 > Hi Laurent, Hi Anthony, > I gave that a shot a little bit ago. Ran into two problems. >=20 > 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=20 > almost immediately. >=20 > Could you guys maybe give compiling QEMU w/libposix-aio a shot? I'm=20 > really interested to see if it makes a difference. Ok, I take a look at this. Regards, Laurent --=20 ------------- Laurent.Vivier-6ktuUTfB/bM@public.gmane.org -------------- "Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke --------------enig9B6FB46A051104007754F32A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.7 (GNU/Linux) iD8DBQFF3G5e9Kffa9pFVzwRAjZPAKCMBIqbTuB48xmd8yVPKUQSt/+lkgCgzZ5W /JXh/qdSuBh8GG4xsdRLvd0= =OvMf -----END PGP SIGNATURE----- --------------enig9B6FB46A051104007754F32A-- --===============0414592886== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- 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=join.php&p=sourceforge&CID=DEVDEV --===============0414592886== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ kvm-devel mailing list kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/kvm-devel --===============0414592886==--