On Sun, Oct 11, 2009 at 04:12:05PM +0200, Fons Adriaensen wrote : > On Sun, Oct 11, 2009 at 02:17:30PM +0200, Aurelien wrote: > > > Perhaps my question is not so-well posed. > > Let's turn it like this: > > > > How is the DSP load appearing in jack computed, and how does it have to > > deal with CPU/Memory/whateverphysicalthing load? > > It is the total time taken by all clients to finish > the processing for one period divided by the period > time. The actual value returned by Jack and shown > in qjackctl and ardour is the maximum of this ratio > over the recent past. > OK. (btw, how is defined the recent past?) > This means that if a jack client sleeps for half a > period time in its process callback (it shouldn't > do that of course) that will show up as 50% in the > 'DSP load', even if it doesn't take any real CPU. OK. > > > Does jack generate an xrun as soon as it reaches 100% DSP load as a > > "security operation" or is it due to hardware limitation when reaching > > 100% DSP load? > > The xruns you see when Jack is running on AlSA are > reported by ALSA. They are usually not related to > DSP load but could have all sorts of causes. If you > have such xruns they will typically show up even > without any Jack client being active. Actually, I do not get any xruns, except when load just comes to 100%. I work with FFADO (unstable) on a Focusrite Saffire Pro 40, and have a quad-core machine with 8Gb. I mainly use synth (alsa modular x4), sooperlooper (2 stereo loopers, 2 mono), tapeutape and some (many) audio routing. I usually work around 80-85% (without sequencer playing) and 90 % load. But sometimes (really not often), I've got this load increase and then an xrun. It could be widely sufficient if it wasn't purposed to play onstage, actually. > > When a process cycle takes too long Jack will detect > this, and AFAIK remove the client that was active > when the new period should have started. This client > may or may not be the one that takes too much time. > OK. > Ciao, > > -- > FA > > Io lo dico sempre: l'Italia è troppo stretta e lunga. > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user > -- Aurélien _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
