[LAU] Again: JACK using too much CPU after a while

Len Ovens len at ovenwerks.net
Thu Aug 25 13:16:05 UTC 2016

On Thu, 25 Aug 2016, Ffanci Silvain wrote:

> Len Ovens, Aug 25 2016:
> ...
>> DSP with Ardour running 3.6 to 3.8% (only two plugins fluidsynth and 
>> reasonable synth just now)
> Just curious: DSP? Do you have an extra board?

No, not beyond the Delta66 itself. There are two measures of system 
busy-ness of interest in an audio system. CPU use just tells how busy the 
CPU is. How much time is it idle and how much time is it working. DSP is a 
measure of how much time is left after the last jack client has finished 
in one buffer cycle. DSP is more important than CPU use for audio work. If 
DSP spikes over 100% you have an xrun. With a realtime kernel CPU might 
hit 100% with no ill affect on audio. (running an audio system with cpu at 
100% is not recomended) If you are using Qjackctl, there will be a yellow 
RT#% (where # is some number) This is DSP use. Ardour also shows this 
number right at the top. CPU use is best shown with htop.

Len Ovens

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