[LAU] audio configuration for ulatencyd

[Tim Blechmann]

>> All processes/threads that inherit the RT privileges from JACK.
> 
> Are these processes parent of jack or do they just connect to it ?
> If these are only connected, how can i get a list of all pids in the graph ?

not sure, if it helps or not, but the audio threads of the jack applications are 
usually started from libjack. however some clients launch separate threads, some 
require rt scheduling policies, some don't ...


>>> • do they need a lot of cpu time ? is 45% not enough for jackd/pulseaudio ?
>> 
>> What is the reason behind 45% ? Wouldn't 99% make more sense? just use
>> the bare minimum to prevent the system from locking up. Am I missing
>> something there?
> 
> I have chosen 45% rt because on a normal desktop the user does not
> expect that some rt task started for whatever reason will eat up all cpu
> power. But of course, for pro audio this is ok. Switching configurations
> in ulatencyd is just a two clicks and a password away. You can change
> the default configuration, too.

the normal desktop user will hopefully not use applications, which eat 100% of 
the CPU with rt tasks. the main point of restricting the CPU time for rt 
applications should be to avoid hard lockups. to achieve this, a cpu limit of 
99% should be as sufficient as a limit of 45%.

many pro-audio users are not musicians, which are not necessarily 
powerusers/system administrators/linux geeks. limiting the cpu time to 45% will 
definitely limit the `it just works' experience!

cheers, tim

-- 
tim at klingt.org
http://tim.klingt.org

I recommend as few rehearsals as possible so that everyone will be slightly
nervous.
  Anthony Braxton