Arch Linux

triplesquarednine

Member

Registered: 2011-04-12

Posts: 630

rtirq can be used on 2.6.39+ kernel

hey folks,

I actually meant to post this a while back.  for those of you who aren't familiar 'rtirq' is a handy little tool, typically used by RT (realtime linux) users.

the use of this little tool is to give certain IRQ (interrupts) higher priorities to ensure better performance without interference, which in the case of multimedia / proaudio users is extremely useful. it can be the difference between a really nice proaudio experience or a crappy one. but it's not exclusive to audio. for example, rtirq affects USB, so there can be added benefit for people using webcams or what-have-you... so those who use VoIP, or have external soundcards can benefit from this...

something you may or may not be aware of is that in 2.6.39, one of the crucial RT patches went mainline, it's called 'forced interrupt thread handlers'.  this can be enabled in any 2.6.39+ kernel by passing 'threadirqs' in the grub/grub2 commandline / entries. (assuming, it is enabled in your kernel config) which will in turn allow you to properly use rtirq.

it can be turned on like so;

sudo /etc/rc.d/rtirq start

or by adding rtirq to your DAEMONs in /etc/rc.conf

this where you add it to grub2;

/etc/default/grub

GRUB_DISTRIBUTOR="Arch Linux"
GRUB_CMDLINE_LINUX_DEFAULT="quiet threadirqs"
GRUB_CMDLINE_LINUX=""

in grub 0.97, you simply add it to;

/boot/grub/menu.lst

root=UUID=fccafcc7-d7cc-4594-9459-a8f0db7b9f7f ro quiet splash threadirqs

it might be of interested to those looking for a little extra juice, or those doing audio work without RT (although 3.0-rt6 is available). I am someone who uses Jack-audio-connection-kit, but even if i wasn't i would probably have this feature enabled.

cheerz