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Date:      Mon, 22 Sep 1997 13:32:20 -0600 (MDT)
From:      Nate Williams <nate@mt.sri.com>
To:        Terry Lambert <tlambert@primenet.com>
Cc:        gibbs@plutotech.com (Justin T. Gibbs), nate@mt.sri.com, current@freebsd.org
Subject:   Re: cvs commit: src/sys/conf files src/sys/dev/vx if_vx.c if_vxreg.h src/sys/i386/apm apm.c src/sys/i386/conf GENERIC files.i386
Message-ID:  <199709221932.NAA02277@rocky.mt.sri.com>
In-Reply-To: <199709221926.MAA16814@usr06.primenet.com>
References:  <199709221559.JAA17865@pluto.plutotech.com> <199709221926.MAA16814@usr06.primenet.com>

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> > >A more deterministic implementation would associate an absolute tick
> > >value (rather than a count) with each entry, and insert entries in
> > >sorted order.
> > 
> > More deterministic for who?  This trades O(1) insertion for O(hash chain
> > length) insertion so that softclock will become O(timeouts for the current 
> > tick).  As timeout often is called from an interrupt context
> > it is not so clear where it is better to pay the price of non-determinism.
> 
> I'm not so sure timeouts should be called from an interrupt context,
> ever.

[ rest deleted ]

We're talking reality here Terry, not theory.

'If the world were a perfect place, we wouldn't need interrupts since we
could get everything done when we needed to and it wouldn't mess with
anything else, but this isn't a perfect world.'

The extra complexity required to do your above solution is *WAY*
overkill.  (I've done things such as it on a small-scale basis, and
performance starts to drop off quickly due to data synchronization when
you have lots of 'objects/drivers'.)



Nate



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