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

[Rohit Damkondwar <genius.rsd@xxxxxxxxx>]

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).
 

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 ?

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 ?

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 ?

Last but not least, patches are always welcomed. ;-)


Wei.

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

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