Re: [PATCH] [request for inclusion] Realtime LSM

Ingo Molnar
2005-01-20T08:06:20Z

* Jack O'Quin <joq@io.com> wrote:

> JACK actually uses three different priorities, the defaults are 9, 10
> and 20. How about if I change this test?
>
> if (prio <= 20 && policy != SCHED_NORMAL) {

yeah, this is OK. 20 is used for the watchdog thread, right? (so it has
minimal latency impact). What's the difference between prio 9 and 10
threads? You might want to map prio 9 ones to nice--15 and prio 10 ones
to nice--20, if there's a real difference between them. But for the
first test i'd suggest to use nice--20 for both. (to make sure
SCHED_OTHER tasks interfere as rarely as possible.)

> Or, should that be?
>
> if (prio > 0 && prio <= 20 && policy != SCHED_NORMAL) {

'prio' cannot get negative here, so the first test is just as fine.

Ingo