Re: [PATCH]O20int

[Con Kolivas]

On Thu, 4 Sep 2003 10:12, Mike Fedyk wrote:
> On Thu, Sep 04, 2003 at 08:55:45AM +1000, Con Kolivas wrote:
> > On Thu, 4 Sep 2003 05:19, Mike Fedyk wrote:
> > > On Thu, Sep 04, 2003 at 12:53:10AM +1000, Con Kolivas wrote:
> > > > Smaller timeslice granularity for most interactive tasks and larger
> > > > for less interactive. Smaller for each extra cpu.
> > > >
> > > > +#ifdef CONFIG_SMP
> > > > +#define TIMESLICE_GRANULARITY(p) \
> > > > +	(MIN_TIMESLICE * (1 << (MAX_BONUS - CURRENT_BONUS(p))) * \
> > > > +		num_online_cpus())
> > > > +#else
> > > > +#define TIMESLICE_GRANULARITY(p) \
> > > > +	(MIN_TIMESLICE * (1 << (MAX_BONUS - CURRENT_BONUS(p))))
> > > > +#endif
> > > > +
> > >
> > > Don't you want to put a max(10,TIMESLICE_GRANULARITY) in there so that
> > > the time slice won't go below 1ms for large proc servers?  I'm not sure
> > > if it was you, or someone else but they did some testing to see how the
> > > timeslice length affected the cache warmth, and the major improvements
> > > stopped after 7ms, so 10 might be a good default mimimum.
> >
> > That works out to 10ms minimum.
>
> With how many processors? 64? 128?

1 cpu = 10ms minimum
2 cpus = 20ms minimum
and so on.

MIN_TIMESLICE * (1 << (MAX_BONUS - CURRENT_BONUS(p))) * num_online_cpus())

works out to:
10 * num_online_cpus()
as the minimum

and 

10 * 1024 * num_online_cpus()

as the maximum

Con

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