sched: fix sleeper bonus

Peter Ziljstra noticed that the sleeper bonus deduction code
was not properly rate-limited: a task that scheduled more
frequently would get a disproportionately large deduction.
So limit the deduction to delta_exec.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-08-12 18:08:19 +02:00
parent 6707de00fd
commit 5d2b3d3695

View file

@ -75,7 +75,7 @@ enum {
unsigned int sysctl_sched_features __read_mostly =
SCHED_FEAT_FAIR_SLEEPERS *1 |
SCHED_FEAT_SLEEPER_AVG *1 |
SCHED_FEAT_SLEEPER_AVG *0 |
SCHED_FEAT_SLEEPER_LOAD_AVG *1 |
SCHED_FEAT_PRECISE_CPU_LOAD *1 |
SCHED_FEAT_START_DEBIT *1 |
@ -304,11 +304,9 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr)
delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw);
if (cfs_rq->sleeper_bonus > sysctl_sched_granularity) {
delta = calc_delta_mine(cfs_rq->sleeper_bonus,
curr->load.weight, lw);
if (unlikely(delta > cfs_rq->sleeper_bonus))
delta = cfs_rq->sleeper_bonus;
delta = min(cfs_rq->sleeper_bonus, (u64)delta_exec);
delta = calc_delta_mine(delta, curr->load.weight, lw);
delta = min((u64)delta, cfs_rq->sleeper_bonus);
cfs_rq->sleeper_bonus -= delta;
delta_mine -= delta;
}
@ -521,6 +519,8 @@ static void __enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
* Track the amount of bonus we've given to sleepers:
*/
cfs_rq->sleeper_bonus += delta_fair;
if (unlikely(cfs_rq->sleeper_bonus > sysctl_sched_runtime_limit))
cfs_rq->sleeper_bonus = sysctl_sched_runtime_limit;
schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);
}