Choppy audio using virtual_oss

[Goran Mekić]

On Tue, Aug 07, 2018 at 11:41:46AM +0200, Hans Petter Selasky wrote:
> You can try.
>
> Check the CPU usage(s). If some process is running close to 100% it won't
> work, you need larger buffers.
>
> I'm a bit worried that the high sample rate combined with libsamplerate will
> overturn the system. Did you try to use 44100 or 48000 Hz. Is there any
> particular reason you are using 88200 Hz ?
>
> Another thing to check is if your kernel is compiled with debugging /
> invariants / witness and such. It will make the character device in
> userspace processing slower.
>
> --HPS

I took some time to do more testing, and when drumgizmo is run as LV2
plugin inside ardour, I experience the problems I described. No matter
what buffer and sample rate parameters I use, the results are the same.
Curiously, when I run drumgizmo as a standalone app and connect it to
ardour via jack audio/midi, everything works fine. At first I thought
it's drumgizmo fault (I'm one of the developers, so it's up to me to
inspect it), but the same symptoms are present using only yoshimi
connected to jack. If I ever figure out what's wrong with jack (I just
presume it's jack's fault), I'll send a patch or howto or something. For
now, I can at least work on my song! :o) Also, CPU now is around 50%
when everything is running, and sampling rate is still 88.2kHz. As I'm
running -RELEASE, there shouldn't be any debugging / invariants /
witness.

Regards,
meka
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