Re: RSDL v0.31

From: Ingo Molnar
Date: Thu Mar 22 2007 - 05:19:32 EST



* Mike Galbraith <efault@xxxxxx> 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.

Ingo
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