Messages in this thread Patch in this message | | | Date | Mon, 15 Jun 2009 21:09:02 +0200 | From | Fabio Checconi <> | Subject | [PATCH 7/8] Reprogram timers only when necessary |
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Avoid unnecessary timer reprogramming when a group is at its full capacity and it is already enqueued. Such a group will not need further budget recharges until it astually consumes its budget, so do not rearm its timer immediately. --- kernel/sched_rt.c | 19 ++++++++++++++++++- 1 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index f43ce7b..a9db16b 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -386,6 +386,19 @@ static int do_sched_rt_period_timer(struct rt_rq *rt_rq, int overrun) return idle; } +static inline int rt_rq_needs_recharge(struct rt_rq *rt_rq) +{ + struct sched_rt_entity *rt_se = rt_rq->rt_se; + + if (rt_rq->rt_time) + return 1; + + if (!rt_se) + return 0; + + return !on_rt_rq(rt_rq->rt_se); +} + static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) { struct rt_rq *rt_rq = container_of(timer, struct rt_rq, @@ -402,7 +415,8 @@ static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) idle = do_sched_rt_period_timer(rt_rq, overrun); } - return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; + return idle || !rt_rq_needs_recharge(rt_rq) ? + HRTIMER_NORESTART : HRTIMER_RESTART; } static void start_rt_period_timer(struct rt_rq *rt_rq) @@ -428,6 +442,9 @@ static void start_rt_period_timer(struct rt_rq *rt_rq) if (overrun) __do_sched_rt_period_timer(rt_rq, overrun); + if (!rt_rq_needs_recharge(rt_rq)) + return; + soft = hrtimer_get_softexpires(&rt_rq->rt_period_timer); hard = hrtimer_get_expires(&rt_rq->rt_period_timer); range = ktime_to_ns(ktime_sub(hard, soft)); -- 1.6.2.2
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