From mboxrd@z Thu Jan 1 00:00:00 1970 From: Håvard Bjerke Subject: Re: Report on Virtualization in Clusters Date: Sun, 28 Nov 2004 12:54:45 +0100 Message-ID: <20041128115445.GI25949@idi.ntnu.no> References: <20041126133225.GR18329@idi.ntnu.no> Mime-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: 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: Ian Pratt Cc: runejoha@idi.ntnu.no, xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org On Sun, Nov 28, 2004 at 11:17:03AM +0000, Ian Pratt wrote: >=20 > > > It seems from your tests without interrupt coalescing that Xen has = a=20 > > > higher interrupt-handling overhead than native Linux. I suppose th= at=20 > > > with the new IO model, Xen needs to flush the TLBs for every interr= upt=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 supp= orted=20 > > > by Xen? > >=20 > > My guess is that it is the former, because we "solved" the problem wi= th the IOAPIC bug with 'ignorebiostables'. Thus using legacy PIC, everyth= ing seemed to behave normally except when not using IC. > >=20 > > I think it boils down to whether or not using legacy PIC as opposed t= o (a supported) IOAPIC has an impact on interrupt handling. If it does, I= think it's the latter reason, otherwise I think it's the former. >=20 > The fact that you had to disable the IOAPIC with ignorebiostables > is rather concerning. It certainly sounds like Xen is really > struggling on your platform. What motherboard chipset are the > machines in your cluster? They are Intel 875P chipsets 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/