[LAU] jack + vanilla kernel

cal cal at graggrag.com
Fri Dec 18 01:01:34 EST 2009


Josh Lawrence wrote:
> quick question:
> 
> if you are using jack with a vanilla kernel, should you still keep the
> realtime option enabled in jack, or run jack without the -R?  my
> reasoning tells me that no realtime patch = no realtime in jack, but I
> just wanted to check myself with you all...
>

Have a look at the SCHED_FIFO section in 'man sched_setscheduler'
 <http://linux.die.net/man/2/sched_setscheduler>
The 'realtime' jack option relates to the use of SCHED_FIFO (ie the
scheduling priority) on selected jack threads (but not all!). The
'realtime' kernel patch relates to different issues, eg, allowing user
processes to preempt kernel processing when possible && appropriate,
thus reducing inherent processing latencies. So the jack -R option is
desirable regardless of which kernel you're running. That's hardly a
complete description of the matter, but I think it's close enough for
now :-).

cheers, Cal
   



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