[LAD] RT

[Pieter Palmers]

Dominique Michel wrote:
> Le Fri, 25 Apr 2008 12:35:43 -0400,
> "Joshua D. Boyd" <jdboyd at jdboyd.net> a écrit :
> 
>> Is it possible to configure a system (included changes to programs) so
>> that nothing can interfere with a few RT threads?
>>
>> I have an audio and video thread in a program, and they are running as
>> SCHED_FIFO, but so many things can interfere with those two threads,
>> such as USB plugs/unplugs, cron log rotations, disk access (PIO flash
>> disk), ssh logins, etc.  I really would like to shore up performance
>> here.
>>
>> I am not using Ingo's RT patches, but I still see people talking about
>> turning off things like cron and server processes to prevent xruns when
>> using Ingo's RT patches.  While I have turned off cron, turning off sshd
>> and the web server aren't options.  I want to instead somehow make sure
>> that neither can every interfere with the AV threads, even if  it means
>> that SSH and web traffic are extremely slow.
>>
> 
> http://proaudio.tuxfamily.org/wiki/index.php?title=Realtime_%28RT%29_Kernel#IRQ_tweaking
> 
> You must use the rtirq package. It is a boot script that use chrt to fix the
> priorities for different IRQ. The trick is to setup the highest priority to the
> rtc (the system will hang otherwise), followed by the sound, followed by the
> other pieces of hardware.

Note that this only works for kernels patched with Ingo's RT patches.

Greets,

Pieter