Re: [Vserver] Shares and Reservations in the token-bucket-algorithm

From: Wilhelm Meier <>
Date: Thu 27 Jul 2006 - 08:50:37 BST
Message-Id: <>

Am Mittwoch, 26. Juli 2006 22:04 schrieb Herbert Poetzl:
> > >
> > > well, not all solaris does is a good idea per se
> > > and I think the current hard cpu scheduler is much
> > > more powerful than the solaris proportional stuff
> > > (i.e. you can consider the solaris settings a subset
> > > of what you can achieve with the hard cpu scheduler)
> >
> > If the solaris fss is a subset, how do I set the token bucket values?
> > With 3 vservers and 0.5 , 0.25 , 0.25 as (fillrate/intervall) for
> > these, how do I get 2/3 for the first and 1/3 for the second vserver
> > if the third vserver is idle as in the solaris fss case? Where is the
> > hidden parameter?
> I take it that you 'simply' want fair scheduling
> between three guests in a 2:1:1 ratio when all three
> guests are hogging cpu, yes?

Yes, the above settings of (fillrate/intervall) should achieve this.

> in this case you simply forget the maximum values
> i.e. set them to something very low to give some
> kind of minimum amount of tokens per time unit, e.g.
> 1/100 and use a set of 2:1:1 for the idle time values
> e.g. 1/3,1/6 and 1/6. once hard cpu and indle time
> is enabled for those guests, they will run in the
> specified ratio, as long as host processes do not
> consume cpu resources, in which case the remaining
> cpu resources will be divided 2:1:1 between them

But what happens if the third vserver falls to idle? In the solaris case the
remaining two vservers would get 2/3 and 1/3 of the cpus (if the host ifself
is idle as well).
In the vserver case we get idle time now: 1/4 with the values above. Then this
idle time is shared amon the three vservers according to the
(fillrate/intervall)_2 for idle time? Well, I don't think this is the same as
in the solaris case. (I mention the solaris case here because in some use
cases this makes sense, not because I think it is superior. I want to get my
understanding of vserver-scheduling right.)

Where can one enable the idle time token bucket? The user-level tools don't
seem to have support for this.

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