Messages in this thread | | | Subject | Re: [PATCH] sched/deadline: comment update for constrained deadline tasks explanation | From | Daniel Bristot de Oliveira <> | Date | Fri, 24 Nov 2017 16:56:14 +0100 |
| |
On 11/24/2017 12:12 PM, Alessio Balsini wrote: > Remove the adjective "relative" associated to the period of a periodic > task, since the period is an absolute value. > > Rephrased the comment with the aim of making it even more clear. > > Signed-off-by: Alessio Balsini <alessio.balsini@arm.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Luca Abeni <luca.abeni@santannapisa.it> > Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it> > Cc: linux-kernel@vger.kernel.org > --- > kernel/sched/deadline.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index f349f7e..902b2e0 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -770,9 +770,9 @@ update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq) > } > > /* > - * Regarding the deadline, a task with implicit deadline has a relative > - * deadline == relative period. A task with constrained deadline has a > - * relative deadline <= relative period. > + * Regarding periodic real-time tasks, a constrained deadline task has the
Not only periodic, but also sporadic. Moreover, for sporadic it is not _period_, but _minimum inter-arrival time_...
IMHO, it is not worth to add such level of details, not even on articles people do, it just turn the explanation more confuse. See this, in the page 5:
http://www-users.cs.york.ac.uk/~robdavis/papers/MPSurveyv5.0.pdf
There is no mention for the kind of period.
> + * relative deadline <= period. An implicit deadline task is a particular case
It is important to keep the "relative" to avoid confusion with the variable "period" which is the "absolute period." I put relative to helps with the ambiguity of the term "period."
-- Daniel
| |