Re: Changes to make /dev/*random better sooner

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Apr 08, 2014 at 10:33:32PM -0400, Thor Lancelot Simon wrote:
> > > -         rnd_add_uint32(&skewsrc, rnd_counter());
> > > -         callout_schedule(&skew_callout, hz);
> > > +         rnd_add_uint64(&skewsrc, rnd_counter());
> > > +         callout_schedule(&skew_callout, hz / 10);
> > 
> > Do we really need to run 10 extra callouts per second to get an extra bit?
> 
> Are you seriously telling me that you are concerned that adding 9 callouts
> per second will measurably impact system performance?

The problem I see with this is with power, especially for embeeded systems.
When we'll go with a tickless kenrel (which I still hope to see), this is
going to wake up the CPU 10 times per second on an idle system.
We should try to avoid that.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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