Re: [vserver] Resource Throttling

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Thu 20 May 2010 - 15:17:45 BST
Message-ID: <20100520141745.GB1743@MAIL.13thfloor.at>

On Thu, May 20, 2010 at 03:03:19PM +0100, --[ UxBoD ]-- wrote:
> ----- Original Message -----
> > On Thu, May 20, 2010 at 02:01:04PM +0100, --[ UxBoD ]-- wrote:
> > > Hello all,

> > > Slowly getting to grips with VServer though have a question over
> > > resource sharing. We have a server with 8 CPUs and 32GB RAM; and 20
> > > contexts running. The nature of each context is a virtual desktop
> > > and recently have experienced a problem where one context has
> > > consumed a
> > > high amount of CPU and memory.

> > > I have read the documentation on context rlimits though am a little
> > > confused on how best to set the fill and interval rates. My aim is
> > > not to impede our desktops, and allow bursting when required, but I
> > > wish to stop runaway processes from bringing down the other
> > > contexts.

> > > The initial thoughts are that we should set each context to
> > > sched_prio
> > > and for the limits use:

> > > fill-rate : 3
> > > interval : 10
> > > max-tokens : 5000
> > > min-tokens : 1000

> > > How do you these values sound ?

> > sound good to me, what kernel/patch do you use?

> > > I see how the values are updated in /proc/virtual/<CTX>/sched though
> > > is there any easy way to keep a running track of how many tokens are
> > > being consumed by each context ?

> > not really, although the number of tokens currently
> > in the bucket is shown too, so it is possible to
> > calculate that (to some extend)

> > HTH,
> > Herbert

> > > Looking forward to any responses.
> > > -- Thanks, Phil

> Hello Herbert,

> Thank you for your response. I am running 2.6.28.7-vs2.3.0.36.7 though
> plan to update too a 2.6.32 kernel in the near future.

in this case you should look into cgroups, as newer kernels
do not use the token bucket scheduler anymore.

http://linux-vserver.org/util-vserver:Cgroups

> Looking at the vsched command it also has options for:

> --fill-rate2 <fill-rate2> --interval2 <interval2>

> how are these used as I was unable to find an example ?

this is used for idle time (i.e. when all guests become
idle, the values fill-rate/fill-rate2 and interval/interval2
are swapped and different shares apply while time is
artificially advance to a point where at least one guest
is able to run again

best,
Herbert

--
if you or your company use and like the Linux-VServer project, 
why not consider donating hardware or money, or getting a
service contract with the developers to ensure that it will
live on and continue to provide high quality free software?
> -- 
> Thanks, Phil
Received on Thu May 20 15:17:59 2010
[Next/Previous Months] [Main vserver Project Homepage] [Howto Subscribe/Unsubscribe] [Paul Sladen's vserver stuff]
Generated on Thu 20 May 2010 - 15:18:04 BST by hypermail 2.1.8