[linux-audio-user] The trouble with disks

Mark Knecht mknecht at controlnet.com
Fri Dec 19 12:28:15 EST 2003

> Yip, 0 overruns on all tests at 2x128.
> Real headscratcher, innit?
> bye
> John

Very perplexing. I've gone back and reread the whole thread. It certainly
seems like you've done all the basics and then much more to debug this. I
doubt anything I write here is actually the root cause and solution, but we
might as well keep trying.

A few questions did come up for me while reading:

1) When you say '0 overruns' above, how did you determine this? I found when
running this test that I'd sometimes get these 'blips' in the scheduling
time that would come close to the breakpoint, but not actually go over. Do
you see anything like that?

2) You said you tried tmpfs. What version of Jack are you using, and did you
recompile Jack to do that test?

3) How are you starting Jack? In a terminal or using qjackctl. I have not
reported this before, but I seem to see more xruns when using qjackctl than
when running Jack in a terminal with the same settings.

4) What command are you generally using to start Jack?

5) Since APIC is not necessary on a uni-processor, have you tried disabling
it at boot time?

6) Possibly important. You said you had a dual-processor up until a few
weeks ago. I presume that you were using the same sound card in that system?
(Thus eliminating the sound card itself as the culprit.) Were you using the
same hard drive?

7) Have you tried looking at this problem with sessions recorded at
different sample rates? In a conversation with another user the other day he
was telling me he gets more xruns at 44.1K than 48K.

- Mark

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