17 Apr
2008
17 Apr
'08
4:02 a.m.
many thanks for all your infos. i'll take a look at the mentioned web-pages.
does anyone want to tell me here some details to the realtime-prios?
thanks a lot
mike
17 Apr
17 Apr
4:20 a.m.
New subject: How to build or from where to get a Low-Latency-Kernel Source
does anyone want to tell me here some details to the
realtime-prios?
Alessio says on the faq:
"Q) Where can I find documentation?
A) All existing docs are available on [WWW] http://rt.wiki.kernel.org"
https://wiki.ubuntu.com/RealTime/Hardy
I use his rt-kernel in Ubuntu, works very well.
Best Regards Asmo Koskinen.
5:22 a.m.
New subject: How to build or from where to get a Low-Latency-Kernel Source
does anyone want to tell me here some details to the
realtime-prios?
After installing rt-kernel in the Ubuntu I have follow these since Dapper
(summer 2006).
1. Add "snd-seq" to the /etc/modules-file.
2. Add "dev.rtc.max-user-freq=1024" to the "/etc/sysctl.conf"-file
3. Add these lines to /etc/security/limits.conf-file
@audio - rtprio 99
@audio - memlock 250000
@audio - nice -10
4. Add these lines to /etc/fstab-file
none /tmp/jack tmpfs defaults 0 0
none /mnt/ramfs tmpfs defaults 0 0
5. Add new mount point
sudo mkdir /mnt/ramfs
6. Mount everything, never mind error message
sudo mount -a
After all these (and rebooting) I can play with M-Audio Keystation 49e.
http://www.arkki.info/howto/Wiki/Hardy_Realtime_01.png
I like to hear is there something I should tweak better or different, as I
said I have used these since Dapper.
Best Regards Asmo Koskinen.
9:54 a.m.
New subject: How to build or from where to get a Low-Latency-Kernel Source
I like to hear is there something I should tweak
better or different, as I
said I have used these since Dapper.
You're good to go. However, a few things to take note of:
* memlock is too low at 250000; 512000 is an ideal number though personally,
I prefer unlimited (2GB of RAM just barely passes with medium-sized projects
in a JACK+Ardour+Hydrogen environment).
* You can build JACK with default tmp as /dev/shm; totally in RAM (no need
for mount options except for /mnt/ramfs which can serve other purposes).
* Reprioritize JACK and your sound card when running real-time. This can be
achieved by appending the following into the "Execute script after Startup"
field of QJackCtl:
chrt -f -p 89 `pidof jackd` && chrt -f -p 99 `pidof IRQ-n` # use "cat
/proc/interrupts" to find out the value of n (sound card IRQ)
Well, these are just "optimisation". In fact, recent kernels and software
have no problem running on a non-RT platform for mediocre tasks.
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