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From: Daniel Phillips <phillips@bonn-fries.net>
To: Andrew Morton <akpm@zip.com.au>,
        Bob McElrath <mcelrath+linux@draal.physics.wisc.edu>
Subject: Re: low-latency patches
Date: Sat, 6 Oct 2001 18:33:42 +0200
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On October 6, 2001 08:46 am, Andrew Morton wrote:
> Bob McElrath wrote:
> > 1) Which of these two projects has better latency performance?  Has anyone
> >     benchmarked them against each other?
> 
> I haven't seen any rigorous latency measurements on Rob's stuff, and
> I haven't seriously measured the reschedule-based patch for months.  But
> I would expect the preempt patch to perform significantly worse because
> it doesn't attempt to break up the abovementioned long-held locks.

Nor should it.  The preemption patch should properly address only what is 
needed to implement preemption, and a patch similar to yours should be 
applied on top to break up the remaining lock latencies.  (Perhaps a duh?)

> (It can
> do so, though - a straightforward adaptation of the reschedule patch's
> changes will fix it).

Yep.

--
Daniel
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