From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: Xen 4.5 development update (July update) Date: Tue, 19 Aug 2014 18:46:51 +0200 Message-ID: <1408466811.3725.62.camel@Solace.lan> References: <20140815172302.2A9FEC33B7@laptop.dumpdata.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============7624840115118493163==" Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XJmZ6-0004QJ-Vv for xen-devel@lists.xenproject.org; Tue, 19 Aug 2014 16:47:21 +0000 In-Reply-To: <20140815172302.2A9FEC33B7@laptop.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: konrad.wilk@oracle.com Cc: artem.mygaiev@globallogic.com, msw@amazon.com, Ian.Jackson@eu.citrix.com, dongxiao.xu@intel.com, mengxu@cis.upenn.edu, feng.wu@intel.com, zhigang.x.wang@oracle.com, parth.dixit@linaro.org, Paul.Skentzos@dornerworks.com, wency@cn.fujitsu.com, rcojocaru@bitdefender.com, guijianfeng@cn.fujitsu.com, Vijaya.Kumar@caviumnetworks.com, josh.whitehead@dornerworks.com, zoltan.kiss@citrix.com, avanzini.arianna@gmail.com, yang.z.zhang@intel.com, xen-devel@lists.xenproject.org, serge.broslavsky@linaro.org, yjhyun.yoo@samsung.com, olaf@aepfle.de, ian.campbell@citrix.com, vijay.kilari@gmail.com, stefano.stabellini@eu.citrix.com, mcgrof@suse.com, julien.grall@linaro.org, dave.scott@citrix.com, robert.vanvossen@dornerworks.com, shantong.kang@intel.com, roy.franz@linaro.org, anthony.perard@citrix.com, andrew.cooper3@citrix.com, ufimtseva@gmail.com, bjzhang@suse.com, eddie.d.ong@intel.co List-Id: xen-devel@lists.xenproject.org --===============7624840115118493163== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-AHDBu+AYTqQKIrO6rjlf" --=-AHDBu+AYTqQKIrO6rjlf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On ven, 2014-08-15 at 13:23 -0400, konrad.wilk@oracle.com wrote: > =3D Open =3D > =3D=3D x86 =3D=3D=20 > * HT enabled, virtualization overhead is high (Xen 4.4) (none) > kernbench demonstrated it > Looking and tracing > http://www.gossamer-threads.com/lists/xen/devel/339409 > - Dario Faggioli >=20 Mmm... I realize only now that I must have missed your last email about this... So, sorry. In any case, didn't we settle on closing it? The bullet is here because very high perf degradation between baremetal and HVM DomU was seen when running `kernbench -j' (i.e., kernbench with unlimited number of build jobs) with HT enabled. Both me and other people tried to reproduce the issue, and here's the number: HT Enabled =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Host Guest kernbench -j4 31.598 (0.113666) 34.078 (0.168582) kernbench -j8 26.676 (0.16772) 26.672 (0.0432435) kernbench -j 27.674 (0.933584) 27.49 (0.364897) To me, this means we don't have an issue of high virtualization overhead when HT is enabled (look at the last row!). All the other things that came up in previous threads are not to be ignored or forgot, of course, and I won't, but they don't have anything to do with this. Let me know, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-AHDBu+AYTqQKIrO6rjlf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEABECAAYFAlPzf3sACgkQk4XaBE3IOsSk7gCcCOP/P2hcnJ/STMjzQhPkdP0k e1cAnR48QYLbgJbwt6rme6AZgXkox8bi =lCKK -----END PGP SIGNATURE----- --=-AHDBu+AYTqQKIrO6rjlf-- --===============7624840115118493163== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============7624840115118493163==--