3 Oct
2007
3 Oct
'07
8:14 p.m.
On Thursday 04 October 2007, Kjetil S. Matheussen wrote:
Well, with a vanilla kernel you simply don't get the fine grained control over
what code gets the cpu at what times as with a realtime-preemption kernel..
It is true that for many people a vanilla kernel with CONFIG_PREEMPT and
CONFIG_HZ=1000 delivers great performance, probably even better than
a "lowlatency" 2.4.x kernel. But basically one badly behaving kernel driver
might cause delay, so for differing people the results differ. With a -rt
kernel you would just give this device a nice and low prio, so it doesn't
even get a chance to disturb the soundcard/jack..
This goes as far that if one sees an xrun while running a properly
setup -rt-kernel one knows it's an application bug or a soundcard driver
bug ;) The kernel itself or any userland processes (X, cronjobs, whatever) as
a source of timing problems are pretty much eliminated.
Regards,
Flo
--
Palimm Palimm!
http://tapas.affenbande.org
For a truly
reliable system (where you can count on no audio period being
missed because you forgot to disable the damn updatedb cronjob) you need
a system patched with ingo's realtime preemption patches and have it
properly configured.
Hasn't this been fixed a long time ago? Its true that you were required to
have a realtime kernel when using linux 2.4 to avoid dropouts for cronjobs
etc., and in practice you probably also couldn't get reliable realtime
performance with old versions of 2.6. But I thought it shouldn't be like
that anymore? At least I haven't had any dropouts with my vanilla 2.6
kernel as long as I've used it.