From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Vivier Subject: Re: Performance comparaison with dbench on KVM Date: Thu, 24 May 2007 16:44:10 +0200 Message-ID: <4655A4BA.5080108@bull.net> References: <46559FDF.5000609@bull.net> <4655A307.3080707@codemonkey.ws> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1909841329==" Cc: kvm-devel To: Anthony Liguori Return-path: In-Reply-To: <4655A307.3080707-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) --===============1909841329== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7C785012464013D5B8D1894E" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7C785012464013D5B8D1894E Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Anthony Liguori wrote: > Laurent Vivier wrote: >> Hi, >> >> I made some benchmarks with dbench on linux/KVM. >> >> IDE means I use an image disk with "-hda" >> SCSI means I use an image disk with "-sda" >> (see the patch I proposed on qemu list: >> http://www.mail-archive.com/qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org/msg08679.html ) >> >> threads KVM-21 KVM-21 KVM-24 KVM-24 KVM-25 KVM-25 >> IDE SCSI IDE SCSI IDE SCSI >> >> 1 215.272 94.8775 318.626 319.533 307.111 331.757 >> 2 212.061 91.3193 313.217 315.163 314.577 323.715 >> 4 197.586 81.7551 291.752 276.044 292.084 271.191 >> 8 144.814 58.5725 188.819 198.995 168.273 165.564 >> 16 111.505 66.3605 139.824 157.617 150.822 123.671 >> 32 43.4109 15.7386 48.2109 50.4114 59.1074 69.5717 >> 64 21.0567 8.3535 11.3457 19.9483 20.4877 24.5627 >> >> results are in MB/sec >> >> Conclusion: >> >> KVM-25 is really better than KVM-21 >> in most cases, SCSI is better than IDE >> =20 >=20 > Were you using libposix-aio? If not, did you change the aio_init=20 > function in block-raw.c (assuming that you're using a raw disk). =20 > Otherwise, QEMU by default will limit the glibc aio library to a single= =20 > thread so you won't see a lot of the benefits of SCSI emulation. Hi Anthony, I didn't modify aio_init limit... I made some benchmarks with liposix-aio, but results are worst with IDE a= nd crashes with SCSI (because I need to make some additional works). It's the part on which I work now (to align buffers to avoid redundant bu= ffer copy and open image disk with O_DIRECT). Regards, Laurent --=20 ------------- Laurent.Vivier-6ktuUTfB/bM@public.gmane.org -------------- "Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke --------------enig7C785012464013D5B8D1894E 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) iD4DBQFGVaS99Kffa9pFVzwRAvb5AJQOinRF64Azvp9yxHYzZlRvH9sqAKCKWy5F +m46wOgcBD2nVwv1GdoAlA== =l9AT -----END PGP SIGNATURE----- --------------enig7C785012464013D5B8D1894E-- --===============1909841329== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ --===============1909841329== 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 --===============1909841329==--