On Tue, 1 Jul 2014 15:08:16 +0200
Peter Zijlstra <pet...@infradead.org> wrote:
> On Sun, Jun 29, 2014 at 09:26:10PM -0400, Zhihui Zhang wrote:
> > Unless we want to double-penalize an overrun task, the time after the
> > deadline
> > and before the current time is already accounted in the negative
> > dl_se->runtime
> > value. So we can leave it as is in the case of dmiss && rorun.
>
> Juri?
>
> > Signed-off-by: Zhihui Zhang <zzhs...@gmail.com>
> > ---
> > kernel/sched/deadline.c | 6 ++----
> > 1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index fc4f98b1..67df0d6 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -579,10 +579,8 @@ int dl_runtime_exceeded(struct rq *rq, struct
> > sched_dl_entity *dl_se)
> > * the next instance. Thus, if we do not account that, we are
> > * stealing bandwidth from the system at each deadline miss!
> > */
> > - if (dmiss) {
> > - dl_se->runtime = rorun ? dl_se->runtime : 0;
If we didn't return 0 before, we are going to throttle (or replenish)
the entity, and you want runtime to be <=0. So, this is needed.
> > - dl_se->runtime -= rq_clock(rq) - dl_se->deadline;
> > - }
A little pessimism in some cases, due to the fact that we use both
rq_clock and rq_clock_task (for the budget).
Thanks,
- Juri
> > + if (dmiss && !rorun)
> > + dl_se->runtime = dl_se->deadline - rq_clock(rq);
> >
> > return 1;
> > }
> > --
> > 1.8.1.2
> >
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