[Ardour-Users] ardour 3.0 alpha season drawing to an end

Robin Gareus robin at gareus.org
Mon Jul 18 03:51:39 PDT 2011

On 07/18/2011 06:34 AM, Al Thompson wrote:
> On 07/16/2011 05:14 PM, Robin Gareus wrote:
>>> This must be what is happening with mine.  Ardour  becomes totally
>>> unresponsive and consumes 100% of the processor for a few minutes (3 or
>>> more), and then settles back down.  This is with a session which has
>>> only two MIDI tracks I was playing with to try out the editor, and the
>>> whole session is only a couple of minutes long.  Up until it locks
>>> itself up, there is no sign of high resource usage.
>> Do you get "JackActivationCount" messages in ardour's Error-Log?

If you don't get the Error-Log filled up with this messages, you are
experiencing a different error.

>> It's not a matter of track-count or session-length. It is a matter of
>> DSP (and CPU) load.
>> I can reproduce it by adding a couple of foo-yc20 organs (LV2synth)
>> which are rather CPU heavy. Just two or three MIDI tracks with a
>> foo-yc20 plugins each are usually enough to trigger the issue here.
>> Only [being patient and] disconnecting ardour from JACK resolves the
>> issue cleanly.
> Well, it didn't completely help here.  I tried using the -S option to
> start jack. Upon loading my existing test session, which is about a
> minute long, has two MIDI tracks, and no plugins, Ardour instantly uses
> around 100% of CPU, locks itself up for several minutes, and says
> "Please wait while Ardour loads visual data."  After it again starts
> responding and CPU usage goes down to normal, it does appear to work
> somewhat better with the -S option.  Rewinding to the session beginning
> no longer locks it up.  I appear to be running into several issues at once.

It certainly seems that there is more to it.

Maybe the "Please wait while Ardour loads visual data." is already a
clue enough for the core-devs to know what may be going on?  Paul? Carl?

It'll certainly help to file a bug-report on the tracker. Include the
console log-output of ardour (highlight the point where it hangs); but I
have a feeling that eventually a back-trace will be necessary to track
this down.

Are you experienced with gdb debugging? IIRC it has been suggested
before (but maybe differnt thread) to get a back-trace of ardour when it
is 100% busy to see what it is doing at the moment it locks.

Let us know how experienced you are with gdb and we'll tell you how to
best approach it :) In general http://ardour.org/debugging_ardour is a
good starting point.

Basically you start ardour3 (from the source-folder) with ./ardbg
wait until it's 100% busy, press CTRL-C and then type
  "thread apply all bt" on the gdb command-line.

Then type "continue" (or simply "c <enter>") and repeat:
 CTRL-C, "thread apply all bt", "continue"

Repeat a few times: There may be more than one location where ardour is

Thanks for your feedback so far,

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