Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.43-00

Lee Revell
2005-04-02T23:46:03Z

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On Sat, 2005-04-02 at 22:35 +0200, Ingo Molnar wrote:
> > For kicks I ran this on 2.6.11-rc2-RT-V0.7.36-02 (I still had it as a
> > Grub option), and the system just locked up hard. I just was curious
> > if this was from a different change. But at least in the latest it
> > shows output, and not just a hard lockup.
> >
> > Oh, the bug report was running kernel 2.6.12-rc1-RT-V0.7.43-06.
>
> ok, so it's not the recent NFS changes.

Here's an interesting trace I got today. It looks either the emu10k1 or
USB irq handler left IRQ 10 disabled. This isn't a tracer bug because
you can clearly see this leads to an xrun. Since I've been hacking the
emu10k1 driver quite a bit, I suspect this is the problem.

This trace also shows that my trigger callback for the emu10k1
multichannel device needs optimizing; it takes 300 usecs to stop all 16
voices, not acceptable for an ALSA irq handler which uses SA_INTERRUPT.
I think I can improve this significantly by reordering the register
settings and eliminating some function call overhead.

Lee

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