Mon Jun 7 12:09:39 CEST 2010
[mouse, etc] are at IRQ 9, whiile the HDSP is at 10. Is this a laptop? If you
have any way of getting the HDSP to IRQ 9 and all the other stuff to IRQ 10,
you will be doing really good. Swap cards in the PCI slots if you can, or check
Failing that, I would try compiling PD 0.37-devel [get it via CVS] with
--enable-alsa and --enable-jack flags. Usually, the Planet CCRMA packages are
pretty good, but you can never be sure. I think Fernando is just starting to
get more into the PD world, as can be seen by the only recent additions of many
crucial PD externals.
Also, as Tim mentions, use a light-duty window manager like Fluxbox [my personal
fav] or Window Maker rather than a flashy, full featured one like KDE or
I noticed that my performance improved when I switched to Gentoo. This not
necessarily because of the Gentoo packages per se, but instead because you can
install a very stripped-down system with Gentoo [or Debian, or Slackware...]
Red Hat tends to install lots of stuff you don't need when doing audio. Do you
really need a mail server running while trying to do realtime audio? Cut down
on all of your overhead and background processes and you will see
---increase your buffer size in PD
---increase your frames per period in Jack
---run at 44100KHz instead of Linux-default 48000KHz sampling rate
---trying running as sudo or root and see if it makes a difference
---always use the -rt flag in PD
---always use the -realtime mode in Jack.
---make sure you have low latency kernel with capabilties patch [CCRMA should
have that covered]
---do you need all those HDSP channels in PD? Try using the -channels flag.
---investigate ways to change the latency of your IRQs and the priority of
processes [renice, for example in the latter case]
---don't run any apps which make constant updates to the screen [such as Gkrell
system monitor, or anything with animations!] while PDing.
---keep your patches clean! Visible arrays of samples, for example, are death to
audio performance. Put things in subpatches, and ask yourself how many
graphical elements are really *necessary* for your patch to run. Graphics which
are updated frequently by PD are just as destructive to sound as graphics in
Unfortunately, running Linux for audio is not like plugging in a Mac. Yet. A lot
of rocket science is still pouring into the field, so for the time being, your
setup will probably be as experimental as your sound.
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