From mboxrd@z Thu Jan 1 00:00:00 1970 From: Håvard Bjerke Subject: Re: Report on Virtualization in Clusters Date: Fri, 26 Nov 2004 14:32:25 +0100 Message-ID: <20041126133225.GR18329@idi.ntnu.no> References: <20041125125424.GO18329@idi.ntnu.no> <41A708F3.3020803@diku.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <41A708F3.3020803@diku.dk> Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Jacob Gorm Hansen Cc: runejoha@idi.ntnu.no, xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org On Fri, Nov 26, 2004 at 11:44:03AM +0100, Jacob Gorm Hansen wrote: > H=E5vard Bjerke wrote: > >Rune and I just finished writing a report on using virtualization with= Xen=20 > >in clusters, with focus on network performance. You may download it fr= om=20 > >http://www.idi.ntnu.no/~havarbj/clust_virt.pdf > > > >We hope you find it interesting! >=20 > Yes, very interesting. Good work. >=20 > It seems from your tests without interrupt coalescing that Xen has a=20 > higher interrupt-handling overhead than native Linux. I suppose that=20 > with the new IO model, Xen needs to flush the TLBs for every interrupt=20 > that arrives. Do you think this is the reason for the overhead, or are=20 > the performance problems only due to your hardware being badly supporte= d=20 > by Xen? My guess is that it is the former, because we "solved" the problem with t= he IOAPIC bug with 'ignorebiostables'. Thus using legacy PIC, everything = seemed to behave normally except when not using IC. I think it boils down to whether or not using legacy PIC as opposed to (a= supported) IOAPIC has an impact on interrupt handling. If it does, I thi= nk it's the latter reason, otherwise I think it's the former. It would be quite easy to verify on the other cluster. I just couldn't fi= nd out how to disable IC on the tg3 driver. The Xen developers could probably give a better answer, though. H=E5vard ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/