Re: [LAU] jackd thinks it's got realtime priority, but it doesn't

On 03/16/2013 12:49 PM, Paul Coccoli wrote:
> I just noticed this on my Fedora 17 system. I run jackd like this:
>
> [paul@email-addr-hidden ~]$ /usr/bin/jackd --realtime -dalsa -dhw:0 -r48000 -p512 -n2
> jackdmp 1.9.9.5
> Copyright 2001-2005 Paul Davis and others.
> Copyright 2004-2012 Grame.
> jackdmp comes with ABSOLUTELY NO WARRANTY
> This is free software, and you are welcome to redistribute it
> under certain conditions; see the file COPYING for details
> no message buffer overruns
> no message buffer overruns
> no message buffer overruns
> JACK server starting in realtime mode with priority 20
> audio_reservation_init
> Acquire audio card Audio0
> creating alsa driver ... hw:0|hw:0|512|2|48000|0|0|nomon|swmeter|-|32bit
> configuring for 48000Hz, period = 512 frames (10.7 ms), buffer = 2 periods
> ALSA: final selected sample format for capture: 32bit integer little-endian
> ALSA: use 2 periods for capture
> ALSA: final selected sample format for playback: 32bit integer little-endian
> ALSA: use 2 periods for playback
> Using port names patch v0.1 (07.04.2010)
> Trying to load portnames from /home/paul/.config/jack/cards/M Audio
> Delta 66.ss.ports.in
> Trying to load portnames from /home/paul/.config/jack/cards/M Audio
> Delta 66.ports.in
> Trying to load portnames from /etc/jack/cards/M Audio Delta 66.ss.ports.in
> Trying to load portnames from /etc/jack/cards/M Audio Delta 66.ports.in
> Trying to load portnames from /home/paul/.config/jack/cards/M Audio
> Delta 66.ss.ports.out
> Trying to load portnames from /home/paul/.config/jack/cards/M Audio
> Delta 66.ports.out
> Trying to load portnames from /etc/jack/cards/M Audio Delta 66.ss.ports.out
> Trying to load portnames from /etc/jack/cards/M Audio Delta 66.ports.out
>
> Everything looks fine, and jackd claims it has realtime mode. I've
> been away from Linux audio for a while, but doesn't realtime mode mean
> RT scheduling? If I check the process's scheduler policy and
> priority, it is NOT RT:
>

it is not the main jackd process which is set to realtime class (FF) but
one of its threads

> [paul@email-addr-hidden ~]$ ps -p 20370 -o cmd,class,pri,rtprio
> CMD CLS PRI RTPRIO
> /usr/bin/jackd --realtime - TS 19 -
>

you should rephrase the ps command line with the -L switch (list
light-weight threads), like so
     ps -p <PID> -L -o tid,class,pri,rtprio,cmd
or, generically
     ps -Leo pid,tid,class,pri,rtprio,comm | egrep "(PID|jackd)"

cheers

-- 
rncbc aka Rui Nuno Capela
rncbc@email-addr-hidden
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