On Sat, 15 Jan 2005 23:04:39 -0500 Eric Dantan Rzewnicki <eric@xxxxxxxxxx> wrote: > I see ingo just posted a preempt patch for 2.6.11-rc1 > http://people.redhat.com/mingo/realtime-preempt/realtime-preempt-2.6.11-rc1-V0.7.35-01 > > > How up to date is the wiki regarding the preempt patches? > http://www.affenbande.org/~tapas/wiki/index.php?Voluntary%20Preemption Sadly not very up to date. I created the pages when this was still very much in flux. Most of the needed info is there though in somewhat obfuscated and confused form. > > I haven't updated my kernel since 2.6.9-rc1-bk12-vp-s0. So, I suspect > I'm a bit behind on the implications of various kernel config options > and what /proc and /sys bits to twiddle. Can someone confirm or deny the > validity of the wiki's data as it relates to the latest patches? > > I currently have 2.6.11-rc1-mm1 running and am not pleased. It basically > works, but I get zipper noises in swh's analogueOsc plugin and a few > xruns from ecasound. I did not have these problems with > 2.6.9-rc1-bk12-vp-s0. > > I am compiling 2.6.11-rc1-V0.7.35-01 now and will report what I find. do you compile it as "Preemptible Kernel (Low-Latency Desktop)" or as "Complete Preemption (Real-Time)"? In the former case, just making all irq handlers threaded except for the soundcard irq handler should give pretty good results already (also run jack at a prio of 60 or 70 in this case). For this the "threaded irq handlers" section on the page you quoted should be accurate. In the latter case all irq handlers are threaded by design, so in this case you need to make sure that our soundcard irq is the highest prio irq handler in the system. Make the soundcard irq handler sched_fifo with prio 98 instead of unthreading it. I always have the keyboard irq handler at prio 99, so magic sysrq works even in the worst cases (i haven't seen negative effects on jack operation yet). The other /proc and /sys stuff is mostly important for debugging. Also when in doubt consult the help texts of the kernel configuration options.. They should have the relevant info, too. flo -- Palimm Palimm! http://affenbande.org/~tapas/
