On Fri, 19 Oct 2018 13:39:42 +0200
Peter Zijlstra <[email protected]> wrote:
> On Thu, Oct 18, 2018 at 01:08:11PM +0200, luca abeni wrote:
> > Ok, I see the issue now: the problem is that the "while
> > (dl_se->runtime <= 0)" loop is executed at replenishment time, but
> > the deadline should be postponed at enforcement time.
> >
> > I mean: in update_curr_dl() we do:
> > dl_se->runtime -= scaled_delta_exec;
> > if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
> > ...
> > enqueue replenishment timer at dl_next_period(dl_se)
> > But dl_next_period() is based on a "wrong" deadline!
> >
> >
> > I think that inserting a
> > while (dl_se->runtime <= -pi_se->dl_runtime) {
> > dl_se->deadline += pi_se->dl_period;
> > dl_se->runtime += pi_se->dl_runtime;
> > }
> > immediately after "dl_se->runtime -= scaled_delta_exec;" would fix
> > the problem, no?
>
> That certainly makes sense to me.
Good; I'll try to work on this idea in the weekend.
Thanks,
Luca
> The only remaining issue would then
> be placing a limit on the amount of times we can take that loop;
> which, as you propose in a later email; can be done separately as a
> limit on runtime.
