[Ardour-Dev] Recording may channels at once

Kjetil S. Matheussen k.s.matheussen at notam02.no
Thu Jul 10 07:38:15 PDT 2008

On Wed, 9 Jul 2008, Sampo Savolainen wrote:

> On Fri, 2008-07-04 at 13:05 +0200, Kjetil S. Matheussen wrote:
>> I just did some benchmarks recording 128 channels (16 X 8):
>> Recording times before failing, without waveforms while recording:
>> 55s
>> 19s
>> 8s
>> Recording times before failing, with waveforms while recording:
>> 16s
>> 24s
>> 18s
>> I run some other programs in the background accessing the
>> disk, so that could explain the large variations.
> Sounds bad though. Can you try the same test so that you use the same
> background load. Preferably no extra load.

It's a bit more consistent now. Below are results without any other
programs running, exept emacs, pine, jack, konsole and qjackctl.
I had 1GB free of memory, and had 5.94s long buffer for ardour.
Total CPU usage was, according to "top", about 20% while recording,
and Jack reported about 12% dsp cpu usage.


The next time I tried, after the result with 19 seconds, something 
interesting happened. Suddenly, after a few seconds, I get a bunch of 
errors which says something like this:

   "can not write peak file, too many open files",

and when I press the stop button, ardour crashes.

I would think this is an OS limitation (although one not very gracefully
handled by Ardour), but anyway, if ardour writes peak files while 
recording, then it's not that strange that jack_capture performs so much 

I guess I got the error because this was the 7th recording, with
128 peak files, yielding about 128*7 files.
This is how I worked:

1. Record.
2. Write down how many seconds of sound recorded.
3. Undo Capture
4. Goto 1.

Why isn't the older peak files closed and deleted?

kjetil at ttleush ~/longrecording/peaks $ ls -la |wc
     874    8730   57091
kjetil at ttleush ~/longrecording/peaks $

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