[alsa-devel] seq: timing unstable on slow computer when busy

Gerald Grabner gerald.grabner at gmx.net
Sat Apr 7 22:52:32 CEST 2007

Hi there,

I'm trying to use a simple (self written) sequencer application on an
old laptop with a 350 MHz CPU. It works, but the timing of output
events becomes unstable when my program is busy with things like
scheduling events for the subsequent loop or an unmuted track.

I'm wondering about the best approach to tackle this problem.
Depending on how the priority of the kernel's event scheduling is
related to the priority of an application, I could imagine some of the
following measures:
* Running my process with lower or higher priority
* Using (priorized) threads for the event scheduling
* Setting Linux kernel config options
* Setting ALSA related options (driver or lib)
* ...

While playing midi, I'm scheduling an echo event a few ticks before
the end of every sequence, upon which a function to schedule the
events of the next sequence is called. What is the typical length of
this scheduling span: Just one bar? Or longer?

Many thanks in advance,

BTW: My operation system is Gentoo's Linux 2.6.19 with alsa-driver

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