WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Xen & I/O in clusters - Single Vs. Dual CPU issue

To: Håvard Bjerke <Havard.Bjerke@xxxxxxxxxxx>
Subject: Re: [Xen-devel] Xen & I/O in clusters - Single Vs. Dual CPU issue
From: Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>
Date: Fri, 29 Oct 2004 20:46:46 +0100
Cc: Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>, Rune Johan Andresen <Rune.Johan.Andresen@xxxxxxxxxxx>, Xen Virtual Machine Monitor <xen-devel@xxxxxxxxxxxxxxxxxxxxx>, Ian.Pratt@xxxxxxxxxxxx
Delivery-date: Fri, 29 Oct 2004 20:49:30 +0100
Envelope-to: steven.hand@xxxxxxxxxxxx
In-reply-to: Your message of "Fri, 29 Oct 2004 20:39:53 +0200." <20041029183953.GB18329@xxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
> The native systems can have either XT-PIC or IOAPIC, and it seems that both 
> have equal performance. In Xen0, however, by looking through dmesg, there 
> doesn't seem to be any IOAPIC. Is it possible to enable (or disable) IOAPIC 
> in Xen0?

If you boot with 'ignorebiostables' on the Xen command line Xen
will ignore the IOAPIC and use the PIC.

I could believe there might be a lurking performance problem with
PIC support as it probably hasn't had the same level of
performance testing as IOAPIC.

Ian
 -=- MIME -=- 
On Fri, Oct 29, 2004 at 06:24:35PM +0100, Ian Pratt wrote:
>=20
> > But, in a dual CPU cluster, Intel Xenon CPU 2.40 GHz  Ethernet=20
> > controller: Intel Corp. 82547GI Gigabit Ethernet Controller, we get=20
> > only 1%
> > (from 114 000 KB/s -> 110 000 KB/s) performance loss.)
>=20
> Good, that's the result we expect.
>=20
> > Hi, we have validated the single CPU results in another single CPU=20
> > cluster, and we still get an performance loss about 30%
> > (ca. 85 000 KB/s between two dom0 nodes (and NOT 114 000 KB/s),
> > Specs:
> > Ethernet controller: Intel Corp. 82547GI Gigabit Ethernet Controller
> > CPU: Intel(R) Pentium(R) 4 CPU 3.40GHz single CPU
> > RAM: 1 GB)
>=20
> Hmm, have your systems got an IOAPIC, or is Xen using the legacy
> PIC code? The latter probably hasn't been thoroughly performance
> tested...
>=20

The native systems can have either XT-PIC or IOAPIC, and it seems that bo=
th have equal performance. In Xen0, however, by looking through dmesg, th=
ere doesn't seem to be any IOAPIC. Is it possible to enable (or disable) =
IOAPIC in Xen0?

H=E5vard



-------------------------------------------------------
This SF.Net email is sponsored by:
Sybase ASE Linux Express Edition - download now for FREE
LinuxWorld Reader's Choice Award Winner for best database on Linux.
http://ads.osdn.com/?ad_id=5588&alloc_id=12065&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel