From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dario Faggioli <dario.faggioli@citrix.com>
Subject: Re: [PATCH] credit: Change default timeslice to 5ms
Date: Wed, 5 Mar 2014 19:04:26 +0100
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To: David Vrabel <david.vrabel@citrix.com>
Cc: Marcus Granado <Marcus.Granado@eu.citrix.com>, Keir Fraser <keir@xen.org>, George Dunlap <george.dunlap@eu.citrix.com>, Tim Deegan <tim@xen.org>, xen-devel@lists.xen.org, Jan Beulich <jbeulich@suse.com>
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On mer, 2014-03-05 at 17:18 +0000, David Vrabel wrote:
> On 05/03/14 16:29, George Dunlap wrote:

> > --- a/xen/common/sched_credit.c
> > +++ b/xen/common/sched_credit.c
> > @@ -29,9 +29,9 @@
> >   * Basic constants
> >   */
> >  #define CSCHED_DEFAULT_WEIGHT       256
> > -#define CSCHED_TICKS_PER_TSLICE     3
> > -/* Default timeslice: 30ms */
> > -#define CSCHED_DEFAULT_TSLICE_MS    30
> > +#define CSCHED_TICKS_PER_TSLICE     1
>=20
> The TICKS_PER_TSLICE change doubles the tick rate.  Is this intentional?
>  It's not mentioned in the commit message.
>=20
Well, I guess higher tick rate is exactly what you expect from reducing
the timeslice... otherwise, you could not be able to enforce the
timeslice boundaries precisely, could you?

It's unavoidable, I think: if you stick with a tick every 30ms/3=3D10ms,
how can you enforce a timeslice of 5ms?

Regards,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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