Exporting Session really slow?

On a non RT kernel environment I have seen that exporting can really hang or freeze ardour. Sometimes I succsefully export but with an extremely painful time cost. While it does that, I can see in qjackctl status of the DSP load a value of 1e+02

On RT kernel this doesn’t happen.

Any ideas or fix?


I have an AthlonXP-2000+ with a standard kernel running Ardour 2.8 and Jack 0.116.1 in non rt-mode.
I also see the DSP pegging at 100% when exporting but the export itself works fine.

Are you running Jack in realtime, using the limits.conf way?
What does 'hdparm -Tt /dev/sda (or what ever drive you have your soundfiles on) ’ say? I have
200.79 MB/sec caches read and 65.42 MB/sec buffered.

Yes Jack is RT using limits.conf the way they should.
hdparm gives me this:

Timing cached reads: 1096 MB in 2.00 seconds = 547.25 MB/sec
Timing buffered disk reads: 166 MB in 3.01 seconds = 55.08 MB/sec

Thing is that DSP load when exporting is not 100% it’s 1e+02% (that’s a really nice high value)
Obviously processor is at fullest

I did try other Jack versions and the result is the same.

bumpity bump anyone?

Just want a confirmation from anyone if this does indeed happen on non RT kernel from anyone of you out there…
And if you know any quick solution or fix to that, or why it happens.


yeah, you are right about that value, I was somewhere else mathematically.
Well this happens with a single mono or stereo track with no plugins. Just for testing, and it still hangs :frowning:

I think 1e+02 is another way of writing 1*10^2, which of course is 100.

And Jack in RT or not, I think it’s either supposed to be that way, or it’s a bug. I bet you’d see that even if you just export one track with no effects on it.

And the versions of Ardour and Jack are…? Hardware info? Time of day? Phase of the moon?

I’d guess an old and buggy Jack but it’s impossible to tell since you omitted to include even a minimum of info regarding the issue (and, yes, the time of day and phase of the moon is extremly important. Never do Ardour work late at night on a full moon. That’s when the werewolves are active, and if they see a light in the window…)

Ah yes! Of course!

Ardour 2.8 (self compiled)

JACK 0.11.62 (self compiled)

qjackctl 0.3.4 (self compiled)
Audio Interface (M-Audio USB Fast Track Pro)

Ubuntu Hardy 8.04 LTS (32 bit)

System RAM (1 GB)

Pocessor (AMD Athlon 64)

Time of Day (Happens every day on non RT kernel)

Moon Phase (Waning Gibbous 84%)

Astrological sign (Pisces)

Chinese Zodiac Sign (Tiger - wood element)

Sex (No sugar or milk)

Hope that does it…


Hello Everyone

First post here.

I’m still fairly new to Linux and Ardour. I’ve been trying out Ardour over the last few weeks and I seem to have developed the same problem, but for me, it happens when using the real time kernel but not when using the regular kernel. I did an export on Tuesday night this week while running rt kernel and everything was fine. Tried another one last night after making some changes to the session and it crashed

I click export, the progress bar moves along to the end, then everything just seems to hang for a few seconds and then Ardour just disappears. Jack shows the same in the message window i.e. 1e+02, but I also have the problem that Jack won’t respond. If I click the ‘stop’ button, my computer locks up and I have to switch off by holding down the power button.

None of this happens (so far) using the regular kernel.

Either way, the file still seems to export fine. I don’t suppose anyone has any ideas?

I’m using Ubuntu 9.04, Ardour 2.7.1, Jack 0.116.1 and Jack Control 0.3.4, Focusrite Saffire LE


almost forgot…

Time of Day - anytime
Moon Phase - Waning Crescent

Did you install all packages from repos? Or something self compiled?

Tip, don’t do a hard reboot by pressing the power button, first try with your keyboard any of the following combos:

Alt-Sys-I (Kill all processes)

Ctrl+Alt+Backspace (Logs you off from your session)

Alt-Sys-B : (Force reboot)

Everything installed from repos and thanks for the keyboard tips

Ok, I have just compiled my own kernel with the USB-Sound patch for M-Audio Fast Track Bus to enable 24 bit recording and higher samplerate, it’s a non RT Kernel, and I must say the results are incredible! (I also compiled it for high memory usage > 64GB), and finally I can record @ 24 bit - 48000

Now when I export I can see the playhead scrolling smoothly during the export process with absolutely no problems.

I am sure it must be some kernel specific issue with the way the ubuntu dudes compile it, because it just doesn’t work right for audio.

So I can tell anyone with this type of issue specifically for those with ubuntu, it’s best to compile an extra kernel and use that for audio production.

What is your H/W Buffer Settings?

Here’s a screen, I can go down to 64 Frames/Period, but do get some xruns at that setting.