Messages in this thread Patch in this message | | | Date | Mon, 15 Jun 2009 21:09:09 +0200 | From | Fabio Checconi <> | Subject | [PATCH 8/8] Use hrtick when available |
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To have a more precise budget enforcement, use the hrtick when available. This comes at the cost of additional overhead; anyway it is disabled by default. --- kernel/sched_rt.c | 32 +++++++++++++++++++++++++++++++- 1 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index a9db16b..38a7be0 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1150,14 +1150,41 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq) return p; } +static void rt_start_hrtick(struct rq *rq, struct task_struct *p) +{ + struct sched_rt_entity *rt_se = &p->rt; + struct rt_rq *rt_rq; + s64 delta, expires = global_rt_period(); + + for_each_sched_rt_entity(rt_se) { + rt_rq = rt_rq_of_se(rt_se); + delta = rt_rq->rt_runtime - rt_rq->rt_time; + expires = min(expires, delta); + } + + /* + * Given the current handling of hrtick in sched_fair, this + * may interfere with sched_fair tasks, generating a spurious + * tick when switching from an RT to a SCHED_OTHER task. + * This is due to the fact that sched_fair reprograms the + * hrtick only in its enqueue/dequeue codepaths. + */ + if (expires > 10000) + hrtick_start(rq, expires); +} + static struct task_struct *pick_next_task_rt(struct rq *rq) { struct task_struct *p = _pick_next_task_rt(rq); /* The running task is never eligible for pushing */ - if (p) + if (p) { dequeue_pushable_task(rq, p); + if (hrtick_enabled(rq)) + rt_start_hrtick(rq, p); + } + return p; } @@ -1794,6 +1821,9 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) { update_curr_rt(rq); + if (queued) + return; + watchdog(rq, p); /* -- 1.6.2.2
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