On Tue, Jun 23, 2009 at 6:19 PM, Fernando Lopez-Lezcano<[email protected]> wrote:
> see here for an interesting entry: > https://bugzilla.redhat.com/show_bug.cgi?id=442959 that is hilarious :) > and > http://bugzilla.kernel.org/show_bug.cgi?id=10361 > (referenced inside the previous ticket) > this is when it was apparently added to the Fedora kernels: > -------- > * Fri Apr 18 2008 Kyle McMartin <[email protected]> - > Enable CONFIG_RT_GROUP_SCHED (#442959) > -------- > > There's something else I'm missing because I'm still able to run rt as a > non-root user even though I have all this stuff. Is Fedora configuring > this somewhere else? Is this overriden by something else? this seems deeply odd. i am also in that same situation. it seems that something *must* be overriding it, but what? >> the API looks entirely usable to me, in the sense that i could easily >> imagine a GUI control panel for this that would be comprehensible to >> most users. > > I think the idea is no control panel :-) yeah, i note that in the second bug report there, peter z. makes some comments about RT scheduling that are not entirely accurate for our use case. we are aiming at deterministic behaviour by each client in a JACK graph, but we don't actually expect determinism across time (e.g. as clients are started and stopped). we're happy to eat 95% of the CPU time, even if we generally expect the typical figure to be more like 10%. this tends to force JACK towards a cgroup that has a perhaps unreasonably large allocation, and a misleading one. AFAICT, the Sum(all cgroup runtime) cannot exceed the rt sched period. So you cannot set things up to allow "JACK" to get 95% and <other RT stuff> to get 95% and just have stuff break if you try to do both. this is good and bad - its an accurate reflection of resource reservation policy, but it doesn't actually reflect what a regular user may want - running two RT subsystems at different times without reconfiguring their cgroups. of course, i have no idea what those two RT subsystems might be, so its a bit moot. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
