Greetings! Welcome, Florian! (I know (of) you from the LAD/LAU lists.) At the moment ChucK is not behaving well under Linux-Jack, and we are committed to tracking this down and hopefully fixing it. Dave Robillard and Gary Scavone (the author of RtAudio) and others have been helping. Some restructuring of the underlying work-flow may be necessary to make ChucK play nice with Jack. However, I am not familiar with Jack development, since we mainly develop on OS X CoreAudio / ALSA / Win32 DirectSound. This may be a good time for me to get familiar with the workings of Jack finally. I am going to fire up yet another Jack-support thread on chuck_dev, and we _shall_ get to the bottom of this. Best, Ge! On Jul 27, 2005, at 3:14 PM, Florian Schmidt wrote:
Hi,
i'm a german nerd/musician and i'm plaing with chuck atm. I succesfully compiled the latest release for jack support. But it seems chuck has some RT issues.
running the mand-o-matic example i get a cpu load of about 2-3% but xruns nonetheless. I run jackd at a buffer size of 256 frames atm (which is plenty huge for my standards. i.e. i use 16 or 32 frames to apply realtime effects to my guitar via jack-rack - completely xrun free. This is a nicely tuned realtime preemption system with a delta 66).
I heard there's a 1.2 version in cvs. Does it have this kind of problem also?
BTW: i get quite a few clicks/pops on moving windows/etc. even w/o
RtApiJack: audio overrun/underrun reported!
and xruns. But there's quite a few of these, too.
Inspecting
~$ ps -C chuck -cmL PID LWP CLS PRI TTY TIME CMD 23421 - - - pts/6 00:00:07 chuck - 23421 TS 24 - 00:00:04 - - 23422 FF 109 - 00:00:02 -
it seems to my uneducated eye, that chuck has two threads. One running SCHED_FIFO (probably the jack process() thread) and another SCHED_OTHER thread. Maybe the RT thread often waits for the SCHED_OTHER thread which gets starved by other cpu activity (like moving windows, etc)
If this is a RTFM! issue i will be happy to accept pointers.
Flo
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