[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] Why two netback drivers? (netback/0 and netback/1)


  • To: Blazej Adamczyk <blazej.adamczyk@xxxxxxxxx>
  • From: Todd Deshane <deshantm@xxxxxxxxx>
  • Date: Mon, 15 Nov 2010 10:40:51 -0500
  • Cc: xen-users@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Mon, 15 Nov 2010 07:45:40 -0800
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:reply-to:in-reply-to:references:from:date:message-id :subject:to:cc:content-type:content-transfer-encoding; b=qxKo+S7cNRXAQesfjo+ZJ4kvz8fcPzRJb5jXLqHBAPUcL4r06Xf82LMaHiX8LAxZDv 6Ij7LZi442X0vdh6c1ZTNIRZHv8wORSsflr60HIpmwAnBZWj8hV5w/xDopUp4uveoqmJ bi5829eooFwymD5Y4Kr+hZ+tdYtzuoF9gK4eg=
  • List-id: Xen user discussion <xen-users.lists.xensource.com>

On Sun, Nov 14, 2010 at 11:02 AM, Blazej Adamczyk
<blazej.adamczyk@xxxxxxxxx> wrote:
> Hello everyone,
>
>
>
> I was looking at Xen networking IO architecture and I really don’t
> understand one thing. On Dom0 right after booting up there are two netback
> kernel threads (netback/0 and netback/1). As I have noticed, they both share
> the tasks related with scheduling the traffic for all DomUs. Having two
> guest domains assigns each netback to a single domain (from my
> observations). But having more guest domains makes them share these two
> processes.
>
>
>
> Can anyone tell me why there are exactly two netback processes? What part of
> the Xen code is responsible for creating them and if I can change
> configuration to have more of them?

My guess is that for performance reasons, multiple threads are used. I
think that if you are really trying to get a better sense of how it is
working internally and how it can be tweaked, then the xen-devel list
would be a better place to discuss such issues.

Hope that helps.

Thanks,
Todd

>
>
>
> There are also loop0, loop1.. processes but they are created for each DomU
> created and as I can guess they are responsible for connecting eth0
> interface with vif interfaces.
>
>
>
> The reason I ask this question is that I was wondering if I can set
> priorities on each DomU network IO operations by changing the scheduling
> policy on the driver domain.
>
>
>
> My configuration is simple:
>
> Domain 0 is also the driver domain. The netback drivers are compiled into
> the kernel. I use Linux Gentoo and Xen 4.0.
>
>
>
> Thanks in advance for any help and comments.
>
>
>
> Best regards,
>
> Blazej
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
>



-- 
Todd Deshane
http://todddeshane.net
http://runningxen.com

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


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.