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SubjectRe: RSDL v0.31
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On Thu, 2007-03-22 at 10:18 +0100, Ingo Molnar wrote:
> * Mike Galbraith <efault@gmx.de> wrote:
>
> > Actually, the numbers are an interesting curiosity point, but not as
> > interesting as the fact that the deadline mechanism isn't kicking in.
>
> it's not just the scheduling accounting being off, RSDL also seems to be
> accessing stale data here:
>
> > >From pull_task():
> > /*
> > * If this task has already been running on src_rq this priority
> > * cycle, make the new runqueue think it has been on its cycle
> > */
> > if (p->rotation == src_rq->prio_rotation)
> > p->rotation = this_rq->prio_rotation;
> >
> > The intent here is clearly that this task continue on the new cpu as
> > if nothing has happened. However, when the task was dequeued,
> > p->array was left as it was, points to the last place it was queued.
> > Stale data.
>
> it might point to a hot-unplugged CPU's runqueue as well. Which might
> work accidentally, but we want this fixed nevertheless.

Erk! I mentioned to Con offline that I've seen RSDL bring up only one
of my two (halves of a) penguins a couple three times out of a zillion
boots. Maybe that's why?

-Mike

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