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Date: Wed, 6 Aug 2003 10:05:17 -0700
From: David Schultz <das@freebsd.org>
To: Jan Grant <Jan.Grant@bristol.ac.uk>
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cc: Roderick van Domburg <r.s.a.vandomburg@student.utwente.nl>
Subject: Re: Tuning HZ for semi-realtime applications
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On Wed, Aug 06, 2003, Jan Grant wrote:
> On Tue, 5 Aug 2003, David Schultz wrote:
> 
> >   100 Hz works just fine for
> > interactive jobs; humans can't tell the difference.[1]
> 
> They can if they're using X :-) I gave Denim* a trial recently; it was
> unusable at 100Hz and fine at 1000.

Yes, polling a tablet device is an interesting case where it
matters.  If you reread my last message carefully, you'll noticed
that I suggested bumping up the default HZ a bit, since the
overhead appears to be well into the noise even at 500 Hz.
An alternative would be to implement a high-resolution timer
facility similar to the Solaris cyclics implementation.