Subject: Re: [linux-audio-user] Jack and Xruns
From: Mark Knecht (mknecht_AT_controlnet.com)
Date: Fri Aug 06 2004 - 17:29:41 EEST
Aaron Trumm wrote:
> Hey y'all - thought I'd ask what thoughts people had on this (very cliche'd and normal, really)
>
> basically the deal is i'm getting a lot more x runs since i changed out my mobo and i'm trying to figure out what else i can do...
>
> i'm running gentoo with the latest ebuilds of jack and ardour, which is what i was doing before, when my motherboard's memory slots and possibly other parts of the board went haywire - it was a soyo dragon plus - so i took the processor out, got new ram (same amount - half gig), and replaced the soyo with a chaintech mobo which I think has the same via chipset (i think)
>
> but what's weird is, i have to run jack at -p 1024 to even HOPE to be able to work, and sometimes at 2048 - hell i even did one mix the other day at 8192 or whatever that step is because i kept getting like one xrun and screwing it up
>
> but before the mobo was replaced (same hd, didn't reinstall OS or kernel but did rsync and update jack and ardour) i could run at -p 256 just fine
>
> so i dicked around, did some hard drive tuning with hdparm, found out about "nice" and tried runnning jack and ardour with nice at the highest 2 priorities, which really seemed to help - but i'm not back to where i can run at 512 or 256 (which is better because you don't get that crazy latency in ardour when you're monitoring what you're recording) - i'm not able to reliably record without having at least one drop out at 1024 which is the highest i've been able to record at withut having ardour actually not place the audio in quite the right spot...with nice maybe i am but i'm still curious what's up that i can't get back to 256...
>
> the only other thing i can think of is that there may be some kernel config options that could stand to be adjusted and the kernel rebuilt...but i so far have been lazy and unconvinced that that'll help...
>
> wow that was a lot of typing...so what do people think?
>
> -------
> NQuit
> www.nquit.com
> -------
>
Hey Mr. NQuit,
How ya been? (Other than the motherboard stuff...)
OK, so xruns are basically an indications that while Jack is running
something gets in the way of it running correctly. Let's look at the
possibilities:
1) Interrupts - If some other card has a higher priority then when it
generates an interrupt, if it's slow responding, then possibly Jack and
the sound card cannot get their job done. Send the output of
cat /proc/interrupts
and
lspci -v
and we'll investigate.
2) Hard drive speed is slower. Send the output of hdparm -tT /dev/hda
(or whatever drive you use for audio) and we'll look at that.
3) If there is some process that interrupts system operation on a
regular basis then that can cause xruns. For instance KDE has a little
app that scans for CD insertions which used to cause xruns for me. Send
the output of ps aux and we'll see what's cooking.
4) On the same track, what environment are you in. I have far fewer
problems with fluxbox than I had with KDE, but others are fine with KDE
so who knows...
All for now.
good luck!
- Mark
This archive was generated by hypermail 2b28 : Fri Aug 06 2004 - 17:34:13 EEST