Re: [Xen-devel] [PATCH] credit: Change default timeslice to 5ms

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

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
> 
> The TICKS_PER_TSLICE change doubles the tick rate.  Is this intentional?
>  It's not mentioned in the commit message.
> 
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=10ms,
how can you enforce a timeslice of 5ms?

Regards,
Dario

-- 
<<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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