On Thu, 22 Dec 2005 02:38:28 +0100 Sylvain Reynal <reynal@xxxxxxxx> wrote: Hi, > Florian, > Is that to say that (cf. your tutorial, > http://tapas.affenbande.org/?page_id=6) reprioritizing IRQ handlers with > things like > chrt -f -p 97 `pidof "IRQ sound_car_irq"` > which prove so simple and efficient with an -rt kernel, are just pointless > with a preemptible kernel (assuming it was compiled with threaded IRQ > handlers)? Which (compiling with threaded irq handlers) is only an option in a -rt patched kernel. Vanilla doesn't have threaded IRQ handlers even in "Preemptible Kernel" mode. Or so i seem to remember. > That'd confirm my recent measurements, but still i can scarcely make out why > this is so. I have no idea. I mostly only run Complete Preemption, which, when it works, works great :) But from my understanding, unthreading the soundcard IRQ handler or setting it to a high priority should be pretty much equivalent from an enduser's point of view (Means: i have no clue, but i bluntly assume). And at the time i actually used preemption modes different from Complete Preemption for audio stuff, they were equivalent. > And while we're at it, i get --amazingly enough-- far more xruns when > un-threading my PCI sound card IRQ handler (doing echo 0 > /proc/irq/...) > than when leaving it threaded... Hmm, this is weird. I'm not sure. It would be best to ask Ingo directly about this. Might be a regression. Regards, Flo -- Palimm Palimm! http://tapas.affenbande.org
