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Subject: Re: 2.6.17-rc6-rt1
From: Thomas Gleixner <tglx@linutronix.de>
Reply-To: tglx@linutronix.de
To: Mike Galbraith <efault@gmx.de>
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Date: Fri, 09 Jun 2006 16:31:36 +0200
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On Fri, 2006-06-09 at 15:42 +0200, Mike Galbraith wrote:
> On Fri, 2006-06-09 at 15:11 +0200, Thomas Gleixner wrote:
> > On Fri, 2006-06-09 at 14:57 +0200, Sébastien Dugué wrote:
> > > All the round trips under strace are in the 2ms range.
> > > 
> > >   How on earth can it be that stracing the ping gives better
> > > performance???
> > 
> > Was busy fixing a scheduling while atomic bug. I just verified that I
> > have the same weird behaviour. I'm looking into it.
> 
> I downloaded and patched a ping.c to do a user triggered latency trace
> around recvfrom() of a ping -c 1 127.0.0.1 running SCHED_RR.  We
> schedule away at 25us, do aaaall kinds of interesting stuff, and come
> back at 42234us.  If you want the trace, holler.  It's 51k bzipped.

Yes, please send it offlist to me.

Thanks, 

	tglx