Automatic realtime IRQ priorities using rtirq
Saturday, 3. January 2009, 15:31:17
UPDATE: I've JUST noticed that there's an RPM at http://www.rncbc.org/jack/ - install and you're away! That man's a genius.
When using audio on Linux, you have to be aware of the the realtime priorities of the system. And even though you may have edited the /etc/security/limits.conf file, the thread priorities of the sound card will not be set.
Rui Nuno Capela [creator of qjackctl and the excellent qtractor] wrote a script to help set the priorities of the most likely IRQs for your system. It didn't require any tweaking; however, when I first tried to use it there were no instructions as to how to apply it. SO...
Now when you enter rcrtirq you'll get
You can only use the command as root unfortunately, but it doesn't matter because this script will now start when you switch your computer on - which means you don't have to think about it!
When using audio on Linux, you have to be aware of the the realtime priorities of the system. And even though you may have edited the /etc/security/limits.conf file, the thread priorities of the sound card will not be set.
Rui Nuno Capela [creator of qjackctl and the excellent qtractor] wrote a script to help set the priorities of the most likely IRQs for your system. It didn't require any tweaking; however, when I first tried to use it there were no instructions as to how to apply it. SO...
- Download the script from http://www.rncbc.org/jack/ (you'll need to head to the end of the page)
- Extract the tar file. For this I used my file browser, PCManFM. No need for the terminal. Yet.
- NOW open a terminal.
- Become root by typing su and the root password.
- Enter cd {path to rtirq script} - this takes you to where the script is.
- Then cp rtirq.conf /etc/ - this copies rtirq's config file to /etc/
- Then cp rtirq.sh /etc/init.d/rtirq - this copies rtirq.sh to the /etc/init.d/ folder, making it a system script. It then renames it as rtirq
- Now enter insserv /etc/init.d/rtirq - this installs the script for the system on startup
- Lastly, enter ln -s /etc/init.d/rtirq /sbin/rcrtirq -this turns the script into a command
Now when you enter rcrtirq you'll get
Usage /sbin/rcrtirq {[re]start|stop|reset|status}
You can only use the command as root unfortunately, but it doesn't matter because this script will now start when you switch your computer on - which means you don't have to think about it!
WIDGETIZE
Anonymous # 27. August 2009, 19:03
how to add this script to Startup?
for real-time priority irq
CrunchBang Linux 9.04.01(un Ubuntu based) ,kernel 2.6.29rt
#!/bin/bash
chrt -f -p 99 pidof 16
Corey Mwamba # 28. August 2009, 05:04
I do not know much about Crunch-Bang Linux I'm afraid - I'm on OpenSUSE here.
If you want real-time priority for IRQs, then follow the instructions in my post, above. As you cannot be sure of the process number each time you start the computer, I think RNCBC's script will be easier to control.
But I guess [and I'm happy to be corrected] that if you followed the instructions I've written from point 3, you could install any script you want!
Hope that helps.
Anonymous # 29. August 2009, 05:39
Hello,
point 2 Extract the tar file. For this I used my file browser, PCManFM. No need for the terminal. Yet.
in which directory to unpack the archive?
Anonymous # 29. August 2009, 18:20
I did everything according to instructions
enter rcrtirq
locke@locke-desktop:~$ rcrtirq
Usage: /sbin/rcrtirq {[re]start|stop|reset|status|force-reload}
All right?
Corey Mwamba # 30. August 2009, 05:58
Originally posted by anonymous:
Any directory for which you have normal user access - for example, where you downloaded the tar file. You could make a new folder for it if you wish and download it to there, then unpack the archive in that folder. Then open a terminal and go to that path.
PCManFM is good for this, since you can go to the Tool menu and open a terminal with its path set to the directory you're looking at.
Once the files have been copied [points 6 and 7], then the tar file becomes unimportant.
Corey Mwamba # 30. August 2009, 06:06
Originally posted by anonymous:
All right!
If you did the insserv step then it should be starting at start-up. I'm not sure how to check that using the command-line, but in OpenSUSE you can check this using YaST: go to System > System Services (Runlevel) and rtirq should be listed there.
Anonymous # 30. August 2009, 12:08
ARIGATO you very much COREY SAN
THANK YOU FOR YOUR ATTENTION
AMAZING MUSIC!!!
Corey Mwamba # 2. September 2009, 06:29
Incidentally, if you do sudo chkconfig in a terminal, you can check if rtirq is running as a service.
Anonymous # 2. September 2009, 19:06
Thank you!!!
not prompt where to download the distributions with the already built rt kernel?
except Ubuntu Studio
example MONTA VISTA?
or all of such distributions are paid?
Corey Mwamba # 19. September 2009, 05:27
Originally posted by anonymous:
It'd be a lot easier if you all put your names.
I don't really understand the question - are you asking where you can find a Linux distribution with a built-in RT kernel? If you are then I think http://www.linux-sound.org/distro.html would be a good start.