lkml.org 
[lkml]   [2005]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: Real-Time Preemption, -RT-2.6.12-final-V0.7.51-12
    From
    Date
    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>

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-07-10 17:47    [W:0.021 / U:0.740 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site