[ardour-users] disk to slow when running plugins

[Peter Hagen]

Thanx for the reply's

I have done some tests:

when i start playback, qjackctl gives me 12 or 13% cpu usage (nice!) and
top gives me about 20% usage. When I come close to the ending of those
regions (and for 15 tracks there are new regions, but for the other 9
their are not) then processor time goes up. I guess to 100%, but it
happens to fast to see. Ardour remains in something near 100% according
to top, allthought qjackctl says 0,27% cpu usage. When I close the
session the cpu usage falls back to 0%

Versions of plugins:
  cabs: 0.3.0
  swh: 0.4.14
  tap-plugins 0.7.0 (this one is from 2004)

I use multiple plugins from the tap project. Specialy the EQ and the
limiter. And there seems to be the problem. It could be that problem
denormals problem, I'm not sure. It looks like that the amount of
plugins running creates the problem, not a single one. I could try to
use different plugins. So does anyone know some good replacements? I use
the Tap EQ cause you can set the frequency (like a band filter i guess?)
and the limiter to reduce peaks

p.

On Fri, 2006-03-31 at 09:41 +0300, Sampo Savolainen wrote:
> Quoting Peter Hagen <peter at wingsofdeath.nu>:
> 
> > Hi
> > 
> > I'm running Ardour 0.99.2 with jackd 0.100.7. I have a session in which
> > i embedded all my tracks. It is 8 songs, with the first 2 contain 24
> > tracks and the other have 15 (need to import the rest). I started to
> > place some busses with plugins for creating a mix (Tap EQ and Limiter).
> > Now when i start playing a little before the end of the second song,
> > Ardour will stotter, then stop and gives me this message "The disk
> > system on your computer was not able to keep up with Ardour.
> > Specifically, it failed to read data from disk quickly enough to keep up
> > with playback.". But, if i deactivate all the plugins, it just keeps on
> > playing. Are there any known issues with the plugins? and is there some
> > way I can prevent this from happening, with using the plugins?
> 
> Sounds like a denormal issue. See 
> 
> http://www.musicdsp.org/phpWiki/index.php/What%20is%20a%20denormal%20number%3F
> 
> for more information.
> 
> Try updating your plugins to the most newest versions. If this doesn't help,
> try disabling all plugins and then enabling them one-by-one until you find
> the one causing the issue. Then email the author about it.
> 
> The way denormals normally strike in ardour are in cases which you just
> described: When a track has a plugin, and the playhead comes to a point in
> the session where there is no more a region on the track. If a plugin has
> some sort of feedback algo, the feedback will get smaller and smaller and
> eventually it will fall into the denormal area and cause this issue.
> 
>   Sampo