[LAU] [Ardour-Users] MIDI workflow

[fred]

Le 17/10/2011 21:43, Edward Diehl a écrit :
> I'm running AVLinux5 with kernel 3.0.6-avl-4 which is not RT but has the
> PREEMPT patch (not really sure of the difference).  My general
> understanding is that with recent kernels the RT patch is not really
> needed.   However, I would think the RT patch would mainly affect latency
> rather than CPU usage.  Also, AVLinux has the rtirq script.   I am a bit
> puzzled by DSP usage, too.
>    
Hi Edward,

sorry for the long book, it may help ?

http://www.restivo.org/blog/archives/sanity-checking-rtirqs

upthere a link that you may like, to dig, and down some useful commands, 
they are the kind of 'howto-reminder' made for the "ok, let's format /, 
I f***** it up again" man than I am !!

For your DSP excessive use, you may pay attention to :
-never use PulseAudio, have only ALSA (and Jack))))
-check if Jack settings and IRQ prios are ok
-killall services and daemons that you don't use for making music (web, 
print, automount, bluetooth...)
-not share IRQ with video
-record audio (Ardour session in fact) in another HD than programs if 
you can
-use a light weight WM (Gnome or Kde are too much "power eaters")

Let me know, I think about trying AVLinux soon (next f***** up near I 
feel))) and like to read your advice on it with some settings done !!
HTH, Good luck,
Fred


# commands #

ulimit -l     will tell you how much memory you can lock

ulimit -r     will tell you at what realtime priority you can run software

uname -r    will tell which kernel is on use

lspci        list the chips

lsmod        list modules loaded at boot

dmesg        read the bootlog

lsi -v|grep audio        list audio chipset

ps -eo cmd,rtprio     will list all the realtime priorities for all your 
tasks

# maybe too much services started ?
ls /etc/rc2.d        list daemons started at boot

# 2.6.29-rt1 = good kernel for P4!

# Maybe you share an IRQ with video ??
ps -eo cmd,rtprio     will list all the realtime priorities for all your 
tasks
cat /proc/asound/cards         will show the IRQs for your cards
cat /proc/interrupts        list IRQs

# RT prio goes like this :
99 watchdog
90 sound card
80 ALSA
70 Jack
60 Ardour

# at the end of /etc/security/limits.conf  (depending your distro, 
sometimes elsewhere or autogenerate when install Jack)    add the 
following (with sudo gedit ie)

@audio   -  rtprio     99
@audio   -  memlock    unlimited
#@audio    -    nice    10

#nice value has nothing to do with real time or latency, forget it !

# jack settings
I record tracks in Ardour with these Jack settings, and it was fine :

-R -P89 -p128 -dalsa -dhw:0 -r48000 -p128 -n3 -D -Pplughw:0 -i2 -o2 -Xseq

Then I try to mix with many plugins, and due to the "formidable" PC I use,
Ardour don't want to do anything...

So, thanks Ralf, I fixed QJackCtrl settings to :

-R -P89 -p128 -dalsa -dhw:0 -r48000 -p512 -n2 -D -Pplughw:0 -i2 -o2

# you can record several settings in QJackCtl...