Messages in this thread | | | Subject | Re: Real-Time Preemption, -RT-2.6.12-final-V0.7.51-12 | From | Peter Zijlstra <> | Date | Sun, 10 Jul 2005 17:43:56 +0200 |
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On Sun, 2005-07-10 at 17:10 +0200, Ingo Molnar wrote: > * Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > > > I can reproduce priority leakage on my SMP system; any userspace process > > > chrt'ed up and a lot will follow. This makes the system very > > > unresponsive when doing a make -j5. Verified on 51-{6,18,23}. > > > > > > > The following patch seems to fix it for me, YMMV. > > > > --- kernel/sched.c~ 2005-07-08 10:27:59.000000000 +0200 > > +++ kernel/sched.c 2005-07-10 13:00:42.000000000 +0200 > > @@ -780,7 +780,8 @@ static void recalc_task_prio(task_t *p, > > } > > } > > > > - p->prio = p->normal_prio = effective_prio(p); > > + p->prio = effective_prio(p); > > + p->normal_prio = unlikely(rt_prio(p->normal_prio)) ? p->prio : __effective_prio(p); > > } > > ahh, indeed, this code did not take boosting into account. Good catch! > I'm wondering why this only showed up on SMP.
I was thinking because of the agressive RT rebalance code this codepath is more exercised on SMP systems.
> I've fixed it a bit > differently in my tree, by making the roles of the various priority > fields and functions more obvious, see the delta patch below.
Yes, much nicer :-)
> I've also > released the -51-23 patch with these changes included. Does this fix > priority leakage on your SMP system? >
-51-24 right? I'll give it a spin.
-- Peter Zijlstra <a.p.zijlstra@chello.nl>
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