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.git branch reorg

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Christophe Saout <christophe@xxxxxxxx>
Subject: Re: [Xen-devel] xen.git branch reorg
From: Boris Derzhavets <bderzhavets@xxxxxxxxx>
Date: Sat, 25 Apr 2009 02:22:20 -0700 (PDT)
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Delivery-date: Sat, 25 Apr 2009 02:22:50 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1240651340; bh=SEzJwle3BKqKSoC1aaGYFQyD7wdAJfmkDOMPjDldY4o=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=l3ZSE5xxqXVqpOYDTew3+32k+c8W+lyNYWBMifXRqW1ku8PelWmiqM9oFHCIcEBxM8ZvJ7j4N2xK3Cuz567Nl6wWXvcKjVdy/2QeYZQM9vTLGT6n95v1piY/+dtD3pdotyOA2QL5ulPEft86quDzXRe+RXg3Hh0RXbOaBmCxsqQ=
Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=yqE7Tb04f7MqTu/LIyaOiyE+YgZBsadaIG/cRo7lZqbQJMc9QrtRzfoScH47+6b6gG5G1K/nI9MMIDYMOcRJRrAbJGef9lX5TynLbLowaPbsSz3zuSf80xfS7QhU7KfmHtpyaBcsAUPDLusmTDfRkfdidK27FXNRUznotmBQQE8=;
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1240612762.1918.5.camel@xxxxxxxxxxxxxxxxxxxx>
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>
Reply-to: bderzhavets@xxxxxxxxx
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
I've just tested:-

# /usr/local/sbin/ethtool -K eth0 tso off

at Ubuntu 9.04 Server PV DomU at Xen 3.4-rc3-pre Dom0 ( with 2.6.30-rc3-tip).
This command also fixes remote VNC connections performance to DomU.

Boris.

--- On Fri, 4/24/09, Christophe Saout <christophe@xxxxxxxx> wrote:
From: Christophe Saout <christophe@xxxxxxxx>
Subject: Re: [Xen-devel] xen.git branch reorg
To: "Jeremy Fitzhardinge" <jeremy@xxxxxxxx>
Cc: bderzhavets@xxxxxxxxx, "Xen-devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Ian Campbell" <Ian.Campbell@xxxxxxxxxx>
Date: Friday, April 24, 2009, 6:39 PM

Hi Jeremy,

> > In meantime time i see, that 2.6.30-rc3&rc2&rc1-tip are
affected.
> > Solution is the same as on Solaris xVM Linux DomUs about one
> > year ago - is to disable checksum (nothing else) offloading at
Linux
> > DomUs ( CentOS 5.3, Ubuntu 9.04)
> >
> > /usr/local/sbin/ethtool -K etho tx off
>
> OK, that's a good lead.

Yes, I've been seeing this too (and meant to investigate it before
claiming there's abug) and I can confirm that turning off segmentation
offloading "cures" the problem here too.

Now the tcpdump on Dom0 looks interesting. It repeatedly sees a packet
with 2880 byte from DomU coming in, which is then dropped and ICMP
"fragmentation needed" sent back, the DomU resends a 1440 byte packet
(after some delay), which then goes through, but then the next one is a
2880 byte one again, and so on.

FYI: My Dom0 is running NAT, in case this is relevant.

Christophe



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