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RE: [Xen-users] How to: Improve Network Throughput of a XEN kernel?

Yes, thank you Boris for pointing that out. I found that was defiantly true. The 3.2.1 xen hypervisor could only boot the 2.6.26-2 xen kernel and the xenified 2.6.31.12.

Additionally I found that:

Xend does not start when using pv_ops dom0 kernel?

In December 2009 pv_ops dom0 kernel modules were renamed to have a "xen-" prefix in them, ie. "evtchn.ko" became "xen-evtchn.ko".

This makes Xen 3.4.x xend fail to start, because it tried to load "evtchn.ko", but that doesn't exist. You need to load "xen-evtchn.ko" and then start xend. Fedora 12 xen-3.4.2-2 rpms have this problem fixed.

Also make sure you have xenfs mounted to "/proc/xen", that's needed aswell.

[Source: http://wiki.xensource.com/xenwiki/XenParavirtOps]

And it appears the Debian xen-3.4.2-2 debs (in squeeze) have not fixed this problem.

Lastly I am still doing some reading on the grub2 package and how to configure it. It turns out that I have been using grub-legacy (or just good old grub) for so long that configuring the grub2 boot loader is turning out to be my own personal kryptonite.

 

I am still working on getting the hypervisor to load the dom0 kernel in a Ubuntu system.

 

I have noticed an example in your wordpress @ Set up Xen 3.4.3-rc2 & Libvirt 0.7.0 Dom0 (with 2.6.31.8 xenified aka Suse kernel) on top of Ubuntu 9.10 Server

 

With CONFIG_CMDLINE="root=/dev/sdb11 ro console=tty0"

 

menuentry "Xen 3.4 / Ubuntu 9.10 kernel 2.6.31.8 xenified" {
insmod ext2
set root=(hd1,10)
multiboot (hd1,10)/xen-3.4.gz
module (hd1,10)/vmlinuz-2.6.31.8
module (hd1,10)/initrd-2.6.31.8.img
}

 

I am sure you wouldn't of mentioned the CONFIG_CMDLINE kernel option is it was not important for using with grub2 right? I have not have to compile a kernel with the command line previous as I was just able to supply the arguments on the kernel line of my menu.lst (grub configuration file).


P.S: What is your feeling on using a recent Ubuntu system with grub-legacy as the boot loader? I noticed that Squeeze has adopted grub2 package as well too...


 
-M





Date: Sat, 27 Feb 2010 04:32:59 -0800
From: bderzhavets@xxxxxxxxx
Subject: Re: FW: [Xen-users] How to: Improve Network Throughput of a XEN kernel?
To: jbeulich@xxxxxxxxxx; mike.viau@xxxxxxxxxxxxxxx
CC: xen-devel@xxxxxxxxxxxxxxxxxxx; xen-users@xxxxxxxxxxxxxxxxxxx

You cannot load pvops kernel under xen-hypervisor 3.2.1  ( >=3.4.0 in general)

Boris.

--- On Fri, 2/26/10, Mike Viau <viaum@xxxxxxxxxxxxxxx> wrote:

From: Mike Viau <viaum@xxxxxxxxxxxxxxx>
Subject: FW: [Xen-users] How to: Improve Network Throughput of a XEN kernel?
To: bderzhavets@xxxxxxxxx, jbeulich@xxxxxxxxxx
Cc: xen-users@xxxxxxxxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx
Date: Friday, February 26, 2010, 3:19 PM

Hello again,

Just a quick update...

I was really hoping it was just going to be an issue with the kernel .config, however I copied exact configuration from the working Debain 2.6.26-2-xen-amd64 kernel and used a make oldconfig but the end result was the same.

After booting the xenified (2.6.31.12) or pvops kernel (2.6.31.6) via both xen-hypervisor 3.2.1 or xen-hypervisor 3.4.2 the maximum data transfer to/from the Dom0 (Xen host) is ~1MB/s.

Next I plan on re-trying my efforts on a Ubuntu system to see if same network bottlenecking is present.




Date: Fri, 26 Feb 2010 09:16:59 -0800
From: bderzhavets@xxxxxxxxx
Subject: Re: [Xen-users] How to: Improve Network Throughput of a XEN kernel?
To: xen-users@xxxxxxxxxxxxxxxxxxx; viaum@xxxxxxxxxxxxxxx

Would escalate to xen-devel.  2.6.31.8 (12) aka Suse xenified  was Jan Beulich stuff.
He might have an answer.
Boris.

--- On Fri, 2/26/10, Mike Viau <viaum@xxxxxxxxxxxxxxx> wrote:

From: Mike Viau <viaum@xxxxxxxxxxxxxxx>
Subject: [Xen-users] How to: Improve Network Throughput of a XEN kernel?
To: xen-users@xxxxxxxxxxxxxxxxxxx
Cc: waldi@xxxxxxxxxx
Date: Friday, February 26, 2010, 12:09 PM

Hi there,

I am starting a new thread to try and solve a problem I am having will slow network throughput to the XEN host (not to a domU).

I have confirmed my problem occurs with PVOPS 'xen/master' kernel as well using http://pasik.reaktio.net/xen/pv_ops-dom0-debug/config-2.6.31.6-pvops-dom0-xen-master-x86_64 as the .config.

It also occurs with a forward ported xenified kernel (2.6.31.12) using the attached config-11-xen (.config).

However when using the xen kernel found in debain lenny (2.6.26-2) for the amd64 architecture I get similiar transfer rates to my Xen host as I do on a baremetel kernel.

Bastian Blank perhaps you could point me in the right direction in regards to a debian specific customization or patch I should be aware of?

Maxium transfer rate (to/from hard disk) using the PVOPS 'xen/master' kernel and forward ported xenified kernel (2.6.31.12) is bottlenecking at ~1MB/s. On the debain lenny xen kernel I am getting ~4.5MB/s.

I was hoping one could suggest options in the .config that might be modified in order to improve network throughput of a XEN kernel and therefor increase the data transfer rates over the netowork to and from the Xen host.

Thanks alot for any help! As always I will be willing to accept any suggestions :)


-M




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