From: Con Kolivas <kernel@kolivas.org>
To: Cliff White <cliffw@osdl.org>, Andrew Morton <akpm@osdl.org>
Subject: Re: 2.6.0-test2-mm3 osdl-aim-7 regression
Date: Thu, 7 Aug 2003 12:40:54 +1000
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Cc: Cliff White <cliffw@osdl.org>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>
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On Thu, 7 Aug 2003 05:10, Cliff White wrote:
> > Binary searching (insert gratuitous rant about benchmarks that take more
> > than two minutes to complete) reveals that the slowdown is due to
> > sched-2.6.0-test2-mm2-A3.

This is most likely the round robinning of tasks every 25ms. The extra 
overhead of nanosecond timing I doubt could make that size difference (but I 
could be wrong). There is some tweaking of this round robinning in my code 
which may help this, but it won't bring it back up to original performance I 
believe. Two things to try are add my patches up to O12.3int first to see how 
much (if at all!) it helps, and change TIMESLICE_GRANULARITY in sched.c to 
(MAX_TIMESLICE) which basically disables it completely. If there is still  a 
drop in performance with this, the remainder is the extra locking/overhead in 
nanosecond timing.

Con

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