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-users

Re: [Xen-devel] Re: [Xen-users] About profiling xen

To: Marco Tizzoni <marco.tizzoni@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: [Xen-users] About profiling xen
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Wed, 30 Sep 2009 09:37:47 +0300
Cc: "Fajar A." <fajar@xxxxxxxxx>, Fasiha Ashraf <feehapk@xxxxxxxxxxx>, xen <xen-devel@xxxxxxxxxxxxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 29 Sep 2009 23:38:11 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <f9611b0f0909292333r7da0c616rbe53ca73a6ea512d@xxxxxxxxxxxxxx>
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/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <196324.1267.qm@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <f9611b0f0909292333r7da0c616rbe53ca73a6ea512d@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.13 (2006-08-11)
On Wed, Sep 30, 2009 at 08:33:19AM +0200, Marco Tizzoni wrote:
>    I experienced the same problem with netperf and with hping also. In
>    general every tool that sends packet at fixed rates seems to suffer this
>    problem. If you use the flood option ( sends packets as fast as possible -
>    for example 'ping -f' or 'hping3 -f') instead of a fixed rate the rate
>    become much higher. What I discovered is this issue should be related to
>    Xen's signal handling/delivery.
>    Netperf use setitimer() to send packets at fixed rate. In my experience on
>    dom0/U, with no load, Xen cannot go over 250 signals per second. Because
>    netperf use signal wakeup the function that send packets I think your
>    problem can be related to this issue. If you want to be sure, count the
>    average number of packet per seconds. It should be about 250 packets/s
>    (not more).


250 per second.. sounds like kernel HZ value? 

-- Pasi

>    For more info you can see
>    
> this:[1]http://lists.xensource.com/archives/html/xen-devel/2009-09/msg01159.html
> 
>    Regards.
>    Marco
> 
>    On Wed, Sep 30, 2009 at 8:07 AM, Fasiha Ashraf <[2]feehapk@xxxxxxxxxxx>
>    wrote:
> 
>      Hi there,
>      I am getting very low throughput (around 0.29Mbps) while running netperf
>      benchmark for guest to guest communication on a single physical host. To
>      analyse where the time is spent in hypervisor I wanna use profiling.
>      Please help me choosing good profiler according to my requirments.
>      Should it be better in my case, Xentrace, gprof, xenoprof  or Oprofile.
>      Is it possible to use some vtune version on FC11?
> 
> References
> 
>    Visible links
>    1. http://lists.xensource.com/archives/html/xen-devel/2009-09/msg01159.html
>    2. mailto:feehapk@xxxxxxxxxxx

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


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