Re: [Xen-devel] dynamically set bandwidth limits of a virtual interface

[Rohit Damkondwar <genius.rsd@xxxxxxxxx>]

On Fri, Dec 28, 2012 at 4:05 PM, Wei Liu <Wei.Liu2@xxxxxxxxxx> wrote:

On Fri, 2012-12-28 at 07:46 +0000, Rohit Damkondwar wrote:
> On Thu, Dec 27, 2012 at 6:03 PM, Wei Liu <Wei.Liu2@xxxxxxxxxx> wrote:
>         On Thu, 2012-12-27 at 08:46 +0000, Rohit Damkondwar wrote:
>         > Hi all. I want to set bandwidth limits to a virtual
>         interface
>         > dynamically(without restarting virtual machine). I have been
>         browsing
>         > xen source code 4.1.3. I looked into libxen
>         folder(xen_vif.c) and
>         > hotplug(linux) folder. Earlier in xen 3.0 , xenvif struture
>         > (driver/net/xen-netback/
>         > interface.c + common.h) and tx_add_credit function could be
>         used to
>         > modify rate limits. I want to change bandwidth limits
>         dynamically of a
>         > virtual interface in xen 4.1.3. Where should I look for in
>         xen 4.1.3?
>         >
>         > Please help.
>         >
>
>
>         Xen vif has a parameter called 'rate', I don't know whether it
>         suits
>         you.
>
> The rate parameter only restricts one way traffic(probably only
> outgoing).
>

Yes, you're right. So you need two way shaping.

>
>         Also, you can have a look at external tool like tc(8). My
>         vague thought
>         is that Vif is just another interface in Dom0, tc(8) should be
>         able to
>         traffic-shape Vif.
>
>
> Don't you think using external tool may decrease the eifficiency ?. If
> xen itself has capabailities ( provided by tc tool ), wouldn't it be
> more efficient ?
>

Do you see significant performance degradation when using tc(8) or any
other tools alike? If so, do report with figures, it can help us
improve. 

 

It doesn't seem like tc gives bad performance. But I cannot say until statistics prove that tc is better.

> I have used this tool. It is good. It serves my purpose. But wudn't it
> be better to include the bandwidth limiting capabilities in xen
> itself? I am not sure about this. Currently I am just browsing through
> the source code. What do u think ?
>

TBH I'm not sure about this either. Again, comparisons and analysis of
bottleneck would be helpful.

>
> I have seen  function "set_qos_algorithm_type" and paramaters
> (qos/algorithm type,qos/algorithm params, qos/supported algorithms) in
> vif class. Would they be useful ? Are they available only for XEN
> Enterprise ?
>

Do you see those in libxen source code? I don't think they are in use
now.

I didn't know that. The when which library should I look into? I could find vif class in libxen folder. So I thought it should be used. I read that xl is not matured enough in xen 4.1.3. So which library should I look into? Please help.

Wei.

--
Rohit S Damkondwar
B.Tech Computer Engineering
CoEP
MyBlog

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel