[PlanetCCRMA] Re: Reliability of the fc2 ccrma kernel?

[Mark Knecht]

Timo,
   Hi. My tests are very minimal and I haven't had time to do any
projects using any version of Fedora (1, 2 or 3) yet so please don't
take my ramblings as recommendations. Overall I'm upbeat about Linux
audio, but I'm still feeling so burned from setting my expectations
too high in the RH8 days that I'm purposely not trying to move too
fast. When I speak here it's entirely about testing and not about
making music. There is a big difference from my experience under
Windows, so take everything with a grain of salt.

   For test purposes I have FC2 on a couple of machines. It's on my
triple-boot (Windows XP, Gentoo and FC2) laptop with just a built in
sound chip. This laptop runs Gentoo most of the time, but for audio I
use it with Pro Tools/Waves under Windows XP. (Meaning I use 1394
audio hardware that is not supported under Linux.) I do, however, test
new Linux code releases (Ardour + VST stuff) on this laptop before I
put it on other machines I care more about.

   On this laptop most of my time is spent in Gentoo, not FC2, and
under Gentoo I can run Jack under low load at 2/16 with no xruns at
all. Yes, that's .7mS latency! Now, low load is not that interesting,
but it shows it can be done with the right hardware and kernel. I can
run alsaplayer or other such small apps, like freqtweak, etc., and
things work fine with no xruns. I have also built my low-latency
kernel under FC2 and run Jack with the same settings but probably only
for a few hours whereas Gentoo is more on the order of weeks or
months. (90% Gentoo, 8% Windows, 2% FC2)

   FYI - so far I have not done significant testing of Fernando's
kernels under FC2. I don't remember the issues but there were a few
when I was looking at them 4-6 weeks ago. Fernando has a new one that
I shoudl try but it's hard to find the time on my laptop.

   I have not tried running Ardour for long periods of time with
settings less than 2/128. This setting seems to work pretty well with
Ardour and Jack, but Ardour still seems a bit too buggy for me to
depend on. It is getting much, much better so I'm spending more time
learning how to do automation in it now. Yesterday I did some Ardour
testing to an external 1394 hard drive and recorded 25 tracks with 5
plugins/track for 5 minutes. I did the test 3 times. Mostly it worked,
but I had one hard power-switch crash which required a 15 minute fsck
when the machine came back up. So much for not having to reboot Linux.
;-)

   I have FC2 on a new machine that has my old HDSP 9652 in it that
never worked well before. This machine is going to use Fernando's
PlanetEdge (tm) kernels if they work well. That's what it's running
right now. Aaron Trumm (NQuit - get his CD!) assures me his card is
doing fine so I'm bringing that machine up and hoping to run Wine and
VSTs on it most of the time. Running that card at 2/64 was never a
problem, but there were lots of frequency change issues with the Alsa
driver and my hardware so I'm not confident right now that this is
going to work well enough to really depend on. We'll see. If not then
I'm moving GigaStudio to that box.

   On my son's PC I have used FC2/PlanetCCRMA for his schoolwork, but
he's playing games and playing with audio apps, so FC2 is good there.
No Jack for him though.

   I have a Windows ME box that runs GigaStudio. I'd like to convert
it to LinuxSampler but I think that project has died again. :-( That
box has some version of RH8 or 9 on it I think. Too long since I
booted Linux.)

   I also have a pretty fast Athlon XP 2600+ box but it runs Gentoo.
It may end up being my main Ardour or Rosegarden box long term. I'd
rather have my laptop do that duty but lack of support for 1394 is a
hinderance right now.

   Don't know if this really answers your questions or not. Hope it
helps though. As I reread my response it's no wonder I'm confused most
of the time. However it's too much writing to throw away so I'll post
it and probably find I've messed up a description somewhere. Too many
machines. Too many things to tie together. I wish my studio was a full
time job! ;-)

- Mark


On Wed, 17 Nov 2004 16:18:46 +0200 (EET), Timo Sivula
<timo.sivula@luukku.com> wrote:
> 
> 
> Hello,
> 
> Mark, you have been announcing success with the 2.6 kernel and Fedora Core 2. What kind of latencies have you reached, and with what values for p and n in Jack? Any xruns?
> 
> Is it worth doing the transition? Fedora Core 3 was just launched, any tests on that platform yet?
> 
> br, Timo
> 
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