10 Feb
2013
10 Feb
'13
6:34 p.m.
I've actually seen some dramatic changes myself. I had great luck with
an ICE1724 based card, but I've noticed that multiple USB audio
devices don't perform as well on the 3.x series kernels compared to my
old trusty 2.6.33, which I realize is ancient now :) I'm wondering if
anyone else has had the same experience. It's only really noticeable
if you're pushing the CPU hard-- it's not a "set to 4x latency" kind
of thing.
But I'd say make super sure you're running at realtime priority. I
can't emphasize how much of a difference that makes. If you're unsure,
do this at a terminal:
ps -eLo cmd,rtprio | grep APPLICATION_NAME_HERE.
Check for your app and for JACK's prio.
Also, grab rtirq and run that if you haven't. I'd assume if you're
using a music-oriented distro that this is all already done.
-Louis
On Sun, Feb 10, 2013 at 9:25 AM, Len Ovens <len(a)ovenwerks.net> wrote:
On Sun, February 10, 2013 8:59 am, Ralf Mardorf wrote:
On Sun, 2013-02-10 at 08:14 -0800, Len Ovens
wrote:
Ok, your machine, but the reply was for someone else. No matter you do say
irqs did change which is what I was saying.
What I am says though is that I'm not sure these problems are kernel
problems. They may be kernel module problems or something else. I have
used all of these kernel versions and been able to run low latency on all
of them no problems (ICE1712 based card). Other people on this list have
had no problems too. Yet there is not just one person with this same
problem. We (on this list) might do well to explore the differences
between our hardware/software to see if we can find the problem.
--
Len Ovens
www.OvenWerks.net
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http://lists.linuxaudio.org/listinfo/linux-audio-user On Sun, February 10, 2013 2:57 am, Folderol
wrote:
The only difference for the IRQ I noticed between older and newer kernel
versions are different IRQs for the graphics. The graphics on my machine
doesn't share it's IRQ with another device any more. One thing I find confusing is the way the kernel
performance changes
so
dramatically from one version to the next.
In debian testing, 64bit V3.1 vanilla works beautifully on my current
machine, but V3.2 requires jack to be set to 4x the latency! That's
for
both
vanilla & RT.
This may or not be it, but try looking at the irq assignment from one to
the next. The kernel sets IRQs for at least some of the devices.