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

[Xen-devel] Direct I/O performance: direct interrupts to running domU?

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Direct I/O performance: direct interrupts to running domU?
From: John Byrne <john.l.byrne@xxxxxx>
Date: Wed, 15 Nov 2006 18:56:22 -0800
Delivery-date: Wed, 15 Nov 2006 18:56:43 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 1.5.0.8 (X11/20061025)
Hi,

I'm testing performance of a NIC assigned directly to a domU. (xen-3.0.3 x86_64)

After your help straightening out the problems with my test environment, my netperf throughput numbers were close to base Linux (generally with 0.5%); however, when I did the netperf transaction tests, the numbers on Xen (either dom0 and domU) were 10-20% lower than the base Linux depending on the test parameters. Since this linear transaction test would be very sensitive to the latency/path-length involved in the interrupt delivery, I'm making the assumption, for the moment, that this is the problem without cranking up xenoprof/oprofile to prove it.

One of the questions that came up in a discussion was whether it might be technically possible to have interrupts delivered directly to a running domain without the hypervisor overhead. This would presumably involve some additional overhead at the time the hypervisor switched domains, but it might be a worthwhile trade-off.

Thanks,

John Byrne









_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>