Re: 2.6.17-rc6-rt1

From: Mike Galbraith
Date: Fri Jun 09 2006 - 09:38:31 EST


On Fri, 2006-06-09 at 15:11 +0200, Thomas Gleixner wrote:
> On Fri, 2006-06-09 at 14:57 +0200, SÃbastien Duguà 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.

-Mike

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