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Subject: Re: [patch] voluntary-preempt-2.6.8.1-P5
From: Lee Revell <rlrevell@joe-job.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
       Thomas Charbonnel <thomas@undata.org>,
       Florian Schmidt <mista.tapas@gmx.net>,
       Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>,
       Mark_H_Johnson@raytheon.com
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On Sat, 2004-08-21 at 05:13, Ingo Molnar wrote:
> * Lee Revell <rlrevell@joe-job.com> wrote:
> 
> > On Fri, 2004-08-20 at 09:30, Ingo Molnar wrote:
> > 
> > >  - reduce ZAP_BLOCK_SIZE to 16 when vp != 0. This pushes the exit
> > >    latency down to below 100 usecs on Lee Revell's box.
> > > 
> > 
> > Almost:
> > 
> > http://krustophenia.net/testresults.php?dataset=2.6.8.1-P6#/var/www/2.6.8.1-P6/trace8.txt
> 
> i suspect if you turn off tracing (or disable it in the kernel
> completely) then you'd see below-100 usec latencies here. A trace entry
> costs ~0.3 usecs on your box, so this 50-entry trace has roughly 15
> usecs of tracing overhead :-)
> 

FWIW, I did see one of these over 200 usecs.

Lee