Re: 2.6 vs 2.4 regression when running gnomemeeting

Christian Meder
2003-12-20T01:54:02Z

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On Sat, 2003-12-20 at 02:26, Nick Piggin wrote:
> Christian Meder wrote:
>
> >On Sat, 2003-12-20 at 01:48, Nick Piggin wrote:
> >
> >>Sounds reasonable. Maybe its large interrupt or scheduling latency
> >>caused somewhere else. Does disk activity alone cause a problem?
> >>find / -type f | xargs cat > /dev/null
> >>how about
> >>dd if=/dev/zero of=./deleteme bs=1M count=256
> >>
> >
> >Ok. I've attached the logs from a run with a call with only an
> >additional dd. The quality was almost undisturbed only very slightly
> >worse than the unloaded case.
> >
>
> OK, its probably not that then. Try the find command though, it would
> be closer to what make/gcc is doing.

Ok. I've attached the find load log. Doesn't feel different from the dd
disk load case. Quality is almost undisturbed.

>
> >
> >>You said it faired slightly better with my scheduler when renicing
> >>gnome meeting to -10. How much better is that?
> >>
> >
> >Worse than unloaded and worse than the disk loaded case from above. But
> >all (CPU) loaded cases were producing almost complete audio dropouts
> >while with your scheduler and renicing to -10 I got at least a
> >stuttering audio stream (a regular pattern of very short slices of audio
> >mixed with very short slices of silence).
> >
>
> So it does sound like scheduling latency then. Its difficult to find
> out what is happening with top and vmstat because they don't give you
> an idea of individual scheduling events, which is what is important
> for things like this. I'll have a look into making up a patch to gather
> what I want to know.

Ok. I will try it then.

>
> In the meantime, I have a newer scheduler patch against 2.6.0 you could
> try: http://www.kerneltrap.org/~npiggin/v28p1.gz

Is this patch supposed to be different schedulerwise from the scheduler
rollup patches against 2.6.0-testx

> Try nicing the compile to +19 if it still stutters.

Ok. I'll try it but I'm not too optimistic about the outcome ;-)

Christian Meder

--
Christian Meder, email: chris@onestepahead.de

What's the railroad to me ?
I never go to see
Where it ends.
It fills a few hollows,
And makes banks for the swallows,
It sets the sand a-blowing,
And the blackberries a-growing.
(Henry David Thoreau)

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