[linux-audio-user] The trouble with disks

John Anderson ardour at semiosix.com
Fri Jan 2 06:10:22 EST 2004

On Fri, 2003-12-19 at 23:24, Jack O'Quin wrote:
> John Anderson <ardour at semiosix.com> writes:
> > This was on vanilla 2.6.0 with Pre-emptible Kernel turned on, for those
> > who've been asking.
> I'm not surprised, -p256 seems a bit too low for reliable operation
> with 2.6 on my system.  It runs, but not well.  Personally, I suspect
> some long paths with preemption disabled in the VM code, just a guess.
> What happens with a 2.4 kernel patched for low-latency?

I've had some more time to play around with things. Eventually I ended
up going back to 2.4.22 patched for low latency and pre-emption. 2.6.0
and 2.6.0-mm2 would both xrun when I was recording. The 2.4 kernel will
record reliably, but I still get dropouts on disk reads.

What's interesting is that if I'm running jack (0.93.6 now, but the last
few releases as well) with *no* connections (except for the automatic
capture and playback ports on the card, 12 and 10 respectively) and I do
anything that involves a fair amount of disk reading (starting ardour,
or cat some-file.wav >/dev/null), I'll get a bunch of xruns.

jackd -R -d alsa -p 256 -n 3, running as root.

It's been while since this thread was started, so here's a refresher on
the box: Uniprocessor Athlon XP 2200+, 1Gb RAM, 36Gb Ultra3 SCSI
(Adaptec 29160 with Fujitsu MAN3367 drive). MSI K7N2 Delta motherboard.
Terratec EWS88MT soundcard. Using reiserfs as the filesystem.

This is all FYI at this point. I'm going to try to get hold of a fast
IDE disk, to see if the problem is somehow related to the SCSI subsystem
or drivers.


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