Messages in this thread | | | Date | Mon, 5 Feb 2018 11:57:08 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] sched/rt: Make update_curr_rt() more accurate |
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* Wen Yang <wen.yang99@zte.com.cn> wrote:
> rq->clock_task may be updated between the two calls of > rq_clock_task() in update_curr_rt(). Calling rq_clock_task() only > once makes it more accurate and efficient, taking update_curr() as > reference. > > Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> > Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> > --- > kernel/sched/rt.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 4056c19..d6d2a65 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -950,12 +950,13 @@ static void update_curr_rt(struct rq *rq) > { > struct task_struct *curr = rq->curr; > struct sched_rt_entity *rt_se = &curr->rt; > + u64 now = rq_clock_task(rq); > u64 delta_exec; > > if (curr->sched_class != &rt_sched_class) > return; > > - delta_exec = rq_clock_task(rq) - curr->se.exec_start; > + delta_exec = now - curr->se.exec_start;
Small nit: shouldn't we calculate 'now' after the return?
OTOH that 'return' should only be triggered statistically AFAICS, i.e. very rarely.
Thanks,
Ingo
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