[linux-audio-user] Looking for soundcard.

Sylvain Reynal reynal at ensea.fr
Mon Dec 19 18:50:27 EST 2005


Lee,
Thank you for your clear explanation. This is a point i'd totally overlooked, 
and leaving the "-n -20" flag in the command line was just 
"so-mechanical" (i.e., a remnant of the time where i'd run jackd w/o the -R 
flag, and where i'd notice slightly better perf ...) I've just redone a 
couple of tests without the -n -20 option and with my 2.6.11-preempt kernel 
this doesn't seem to change anything indeed (wooow, thanks god, there are no 
serious bugs ;-)))

Now, looking back on this, I must admit i also got a bit muddled up over 
"nice" vs "priority" issues when i recently started working with a 2.6.14-rt 
kernel. I could read in a previous post on this list that -to sum up- one 
should have jackd running at a priority "higher than all irq handlers besides 
the soundcard irq" (where soundcard=ieee1394 controller in my case): as i 
take it, running jackd with, e.g., -P -70, simply increases the RT scheduling 
priority of jack then (irrespective of the nice value of the non-RT part of 
jackd if i understand what you said). Am i right?

(btw, jackd -P anynegativenumber triggers an error with my 2.6.14-rt kernel, i 
get a "cannot use real-time scheduling (FIFO at priority -70) etc."; probably 
the subject for another thread though)

Regards,
Syd

> Running [jackd]
> at a low nice value could cause non real-time parts of JACK to interfere
> with the audio engine.





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