intermittent RT status in qjackctl

[duffrecords]

I have a brand-new installation of UbuntuStudio 9.04 (64-bit) and I built JACK2 from svn. When I start jackd the yellow RT indicator in qjackctl turns on and off intermittently. I'm a member of the audio group and limits.conf has been set as follows:
@audio - rtprio 99
@audio - nice -10
@audio - memlock unlimitedI'm not sure what's wrong, as I had these same JACK parameters working in Hardy Heron and Debian Lenny:/usr/bin/jackd -v -R -P89 -dalsa -dhw:1,0 -r48000 -p128 -n2Is it just trouble with the new kernel?

[thorgal]

same here, it's just a normal behavior :)

To know if jackd runs some of its threads in RT, just type this in the terminal:


ps -Leo class,comm,rtprio | grep jack


if you see stuff like this

RR jackd 70
RR jackd 65

you should be good.

old article but you can read this:
http://www.informit.com/articles/article.aspx?p=101760&seqNum=4

SCHED_RR and SCHED_FF are both RT scheduling prio. SCHED_RR is like SCHED_FF with time slices.

[raboofje]

same here, it's just a normal behavior :)

This got me confused in the past, too :).

[duffrecords]

This is the thread info:TS jackd -
TS jackd -
TS jackd -
FF jackd 99
FF jackd 89Does that look normal?

[duffrecords]

Interesting. If I start qjackctl with the priority set to (default) rather than 89 as it was in the previous example, I get this:TS jackd -
TS jackd -
TS jackd -
FF jackd 20
FF jackd 10Those look like nice values.

[thorgal]

I set my jackd prio to 70 (look in the qjackctl setup window, a field called "priority")

99 seems wway too much and should be reserved to the softirq-timer's (not even sure about that one)

try:

ps -Leo comm,class,rtprio | grep timer


and to check that your audio card interrupt is also SCHED_FF, check this"

sudo /etc/init.d/rtirq status


that is, if you have the rtirq script. I am not sure whether ubuntu studio comes with it. I know 64 Studio ships it. There's a deb available in the 64 studio repos that you can always try to install:

http://www.mirrorservice.org/sites/64studio.com/apt/pool/main/r/rtirq/rtirq_20070101-1_all.deb


sudo dpkg -i rtirq_blabla.deb


Your system services will start rtirq at boot time. You can also do it manually with

sudo /etc/init.d/rtirq start

You can tweak it in /etc/default/rtirq (text file with options that are relevant for your system)

[duffrecords]

Looks like the audio card interrupt is SCHED_FF. It's a Roland SI-24 (the one in my profile avatar) with an RPC-1 card (using the ICE1712 chip). PID CLS RTPRIO NI PRI %CPU STAT COMMAND
120 FF 90 - 130 0.0 S< IRQ-8 rtc0
2130 FF 85 - 125 0.0 S< IRQ-17 ICE1712
117 FF 84 - 124 0.0 S< IRQ-20 ohci_hcd:usb3, HDA Intel
116 FF 80 - 120 0.0 S< IRQ-21 ehci_hcd:usb2, nvidia
115 FF 79 - 119 0.0 S< IRQ-22 ehci_hcd:usb1
118 FF 79 - 119 0.0 S< IRQ-23 ohci_hcd:usb4
119 FF 75 - 115 0.0 S< IRQ-1 i8042
76 FF 50 - 90 0.0 S< IRQ-9 acpi
104 FF 50 - 90 0.0 S< IRQ-2299 PCI-MSI-edge ahci
111 FF 50 - 90 0.0 S< IRQ-14 pata_amd
112 FF 50 - 90 0.0 S< IRQ-15 pata_amd
431 FF 50 - 90 0.0 S< IRQ-6 floppy
547 FF 50 - 90 0.0 S< IRQ-19 ohci1394
2091 FF 50 - 90 0.0 S< IRQ-18 cx18-0
2988 FF 50 - 90 0.0 S< IRQ-2298 PCI-MSI-edge eth0
3228 FF 50 - 90 0.0 S< IRQ-4
4441 FF 50 - 90 0.0 S< IRQ-16

[duffrecords]

ps -Leo comm,class,rtprio | grep timer
sirq-timer/0 FF 50
sirq-hrtimer/0 FF 50
posix_cpu_timer FF 99
posix_cpu_timer FF 99
sirq-timer/1 FF 50
sirq-hrtimer/1 FF 50
posix_cpu_timer FF 99
sirq-timer/2 FF 50
sirq-hrtimer/2 FF 50
posix_cpu_timer FF 99
sirq-timer/3 FF 50
sirq-hrtimer/3 FF 50