Re: [Jack-Devel] jack dsp load calculation

On 26 Dec 2015, at 15:38, Robin Gareus wrote:

> 
> My criticism is that jack's currently algorithm does not satisfy the
> criteria: "an x-run implies 100% reported load".
> 
> How can we justify buffer over/under-runs if there is time left to
> process the buffer?
> 

Huh?  You've already pointed out that any value higher than 95% gets reported verbatim (i.e. without getting factored into any averaging).  So why will 100% not get reported correctly?

The problem here is that Ardour's DSP printout is NOT intended to highlight xruns (not in any sense).  It's simply a display (in green) which turns to red when the value gets worryingly high.

BUT... it only gets updated once every second.  And since the display isn't (currently) affected in any way by xruns, if an xrun happens to occur in between 2 updates it can go unreported (as far as that DSP reading is concerned).  Removing Jack's averaging won't fix that problem.

HOWEVER... Ardour already has a mechanism for registering xruns.  So if we want xruns to get reflected somehow in that DSP printout, we can already achieve that within Ardour.  It's not necessary to modify Jack.

John

1451147237.5755_0.ltw:2,a <E00351EB-D505-4489-A0C8-E9D0873B4240 at tiscali dot co dot uk>