Re: 2.6 vs 2.4 regression when running gnomemeeting

[Andrew McGregor]

Hmm.  Gnomemeeting has a history of strange threading issues (actually, all 
OpenH323 derived projects do).  Is there a threading change that might 
explain this?

Andrew

--On Saturday, 20 December 2003 4:32 a.m. +0100 Christian Meder 
<chris@xxxxxxxxxxxxxxx> wrote:

> On Sat, 2003-12-20 at 03:55, Con Kolivas wrote:
> > On Sat, 20 Dec 2003 13:38, Nick Piggin wrote:
> > > Christian Meder wrote:
> > > > 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.
> >
> > Since so many things have actually changed it's going to be hard to
> > extract  what role the cpu scheduler has in this setting, but lets do
> > our best.
> >
> > Is there a reason you're running gnomemeeting niced -10? It is hardly
> > using  any cpu and the problem is actually audio in your case, not the
> > cpu  gnomemeeting is getting. Running dependant things (gnomemeeting,
> > audio  server, gnome etc) at different nice levels is not a great idea
> > as it can  lead to priority inversion scenarios if those apps aren't
> > coded carefully.
> >
> > What happens if you run gnomemeeting at nice 0?
>
> Exactly the same. It was only reniced to -10 because I tried it and
> forgot to set it back. With your scheduler renicing doesn't make a
> difference. No matter if I renice the compile to 19 or gnomemeeting to
> -10. With Nick's scheduler renicing gnomemeeting to -10 improves the
> situation.
>
> > How is your dma working on your disks?
>
> /dev/hda:
>  multcount    =  0 (off)
>  IO_support   =  0 (default 16-bit)
>  unmaskirq    =  0 (off)
>  using_dma    =  1 (on)
>  keepsettings =  0 (off)
>  readonly     =  0 (off)
>  readahead    = 256 (on)
>  geometry     = 65535/16/63, sectors = 117210240, start = 0
>
> > What happens if you don't use an audio server (I'm not sure what the
> > audio  server is in gnome); or if you're not using one what happens when
> > you do?
>
> esd was running but I'm not sure gnomemeeting with ALSA support was
> using it. After killing esd and retrying there was no difference.
>
> > Renice the audio server instead?
>
> gnomemeeting without audio server is showing the same phenomenon like
> gnomemeeting with esd.
>
> > You've already tried different audio drivers right?
>
> Yes, the phenomenon occurs for the OSS and the ALSA driver.
>
> > Nice the compile instead of -nicing the other stuff.
>
> Tried it with same result (see above).
>
> > Try the minor interactivity fix I posted only yesterday for different
> > nice  level latencies:
> > http://ck.kolivas.org/patches/2.6/2.6.0/patch-2.6.0-O21int
>
> Actually all the posted results were on a 2.6.0-test11-mm1 with your
> patch added on top. So the patch didn't change anything for me.
>
> > Is your network responsible and the audio unrelated? Some have reported
> > strange problems with ppp or certain network card drivers?
>
> The problem occurs whether I use my WLAN PCMCIA card or my PCMCIA
> Ethernet card.
>
> > As you see it's not a straight forward problem but there's some things
> > for you  to get your teeth stuck into. As it stands the cpu scheduler
> > from your top  output appears to be giving appropriate priorities to the
> > different factors  in your equation.
>
> I know that the problem isn't straight forward that's why I refrained a
> long time before posting to linux-kernel trying to rule out different
> scenarios. As it stands I tried different gnomemeeting versions,
> different audio drivers, different nice levels, different schedulers,
> preemption on and off, ACPI on and off, -mm kernels and pristine Linus
> kernels with no luck. If I put CPU load on my box the gnomemeeting
> audiostream gets badly mutilated (unusable). There's not much left I can
> think of that's why I'm finally posting to linux-kernel.
>
>
>
> 				Christian Meder
>
>
> --
> Christian Meder, email: chris@xxxxxxxxxxxxxxx
>
> 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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---------
Andrew McGregor
Director, Scientific Advisor
IndraNet Technologies Ltd
http://www.indranet-technologies.com/
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