Re: [LAU] Too many xruns

On Thu, September 6, 2012 8:43 am, Kevin Cosgrove wrote:
> On 5 September 2012 at 22:28, "Len Ovens" <len@email-addr-hidden> wrote:

> This is looking as complicated as slackware was in 1996, back
> when I had to build a special kernel with each OS release.

Been there done that. This was before modules and even for a while after.

MB manufactures have not really built with audio use in mind (or perhaps
any RT use) except for the internal audio IF which you will notice has the
highest irq (which has the highest priority on an OS that doesn't have
secondary prioritizing like Linux) And that it does not share it's irq
with anything. And they are not even looking for low latency. New MBs
expect any timing critical to be in the PCIe slots... They figure the old
PCI stuff was used to slow machines ... Still a good bios may be able to
change this. Maybe take one of the slots out of PNP mode and assign a
clear or almost clear irq (may have to be in the 1-16 range) The MB may
then work around that.

I am working with a slow and cheap (did I say cheap?) netbook. By default
the internal sound IF gets an xrun/minute from wireless... turning
wireless off is worse it goes to an xrun/5seconds. I have to unload the
ath9k (I think) kernel module to get rid of that. -p 128 is the lowest
latency the internal IF will allow jack to start at. I have a USB IF (ART
dual tube pre) that can do -p 64... if it is plugged into the right usb
port and rtirq is set up right etc. If pulse is outputting to the internal
card as well as Jack sink, then the problems with the internal IF are
forced onto the external IF. That is I can no longer get jack to start at
-p 64 on the external IF.

Anyway, I have to work a bit harder to get things working the way it
should. It will run pulse->jack reliably with good latency (not sure why I
would do that) I can use it as a guitar effect with guitarix at -p64 or
128. Or even as a softsynth with more than one synth at a time. For
recording I would back the latency off to at least 1024 and monitor
externally(hardware).

Other tricks I use? I turn cron and friends off and mysql (used by
lyricue). I set performance or a least a set speed. Swappiness 10 (all the
time for this) as qjackctl seems to be one of the first things to swap out
:P

-- 
Len Ovens
www.OvenWerks.net
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user