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/
Home Products Support Community News


RE: [Xen-users] decreasing Xenmon overhead

To: "Ashish Gupta" <ashishgup@xxxxxxxxx>, Xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] decreasing Xenmon overhead
From: "Petersson, Mats" <Mats.Petersson@xxxxxxx>
Date: Wed, 30 May 2007 12:07:47 +0200
Delivery-date: Wed, 30 May 2007 03:06:25 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <fcc5876b0705291253u2b2cdccfk4880c3fec7fab25f@xxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AceiKyNtA6G24Iv7RXqGh+JLN0K/PwAdwLyA
Thread-topic: [Xen-users] decreasing Xenmon overhead

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Ashish Gupta
> Sent: 29 May 2007 20:54
> To: Xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-users] decreasing Xenmon overhead
> Hi,
> I have been trying to run xenmon in its logging mode to 
> collect statistics for offline analysis. However  I notice 
> that at an interval of 100 ms or so the overhead imposed by 
> dom0 is quite high , with upto 40% of CPU utilization.

Yes, simply don't use 100ms inervals?

> Are there ways I can drastically reduce this overhead ? I 
> read somwhere about event overhead, using event masks and 
> python overhead,  but am not really sure how to use this 
> information to reduce the overhead. 

Perhaps write a C-program rather than using Python to fetch/format the
information? That shouls improve it, but I guess you'll still see a
noticable overhead if you sample the information every 100ms. 

I'm not sure it's that meaningfull to run it that frequently, really. 

> Any help is greatly appreciated !
> thanks,
> Ashish

Xen-users mailing list