diff options
author | Peter Zijlstra <peterz@infradead.org> | 2009-09-16 10:31:31 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-09-17 08:17:25 (GMT) |
commit | ad4b78bbcbab66998b05d422ac6106b645796e54 (patch) | |
tree | 45f3561f4bd6b886948a3b0eea64edab9bab9eda /kernel | |
parent | eb24073bc1fe3e569a855cf38d529fb650c35524 (diff) | |
download | linux-fsl-qoriq-ad4b78bbcbab66998b05d422ac6106b645796e54.tar.xz |
sched: Add new wakeup preemption mode: WAKEUP_RUNNING
Create a new wakeup preemption mode, preempt towards tasks that run
shorter on avg. It sets next buddy to be sure we actually run the task
we preempted for.
Test results:
root@twins:~# while :; do :; done &
[1] 6537
root@twins:~# while :; do :; done &
[2] 6538
root@twins:~# while :; do :; done &
[3] 6539
root@twins:~# while :; do :; done &
[4] 6540
root@twins:/home/peter# ./latt -c4 sleep 4
Entries: 48 (clients=4)
Averages:
------------------------------
Max 4750 usec
Avg 497 usec
Stdev 737 usec
root@twins:/home/peter# echo WAKEUP_RUNNING > /debug/sched_features
root@twins:/home/peter# ./latt -c4 sleep 4
Entries: 48 (clients=4)
Averages:
------------------------------
Max 14 usec
Avg 5 usec
Stdev 3 usec
Disabled by default - needs more testing.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <new-submission>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/sched.c | 17 | ||||
-rw-r--r-- | kernel/sched_debug.c | 1 | ||||
-rw-r--r-- | kernel/sched_fair.c | 14 | ||||
-rw-r--r-- | kernel/sched_features.h | 5 |
4 files changed, 27 insertions, 10 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 969dfae..3bb4ea2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2458,6 +2458,7 @@ static void __sched_fork(struct task_struct *p) p->se.avg_overlap = 0; p->se.start_runtime = 0; p->se.avg_wakeup = sysctl_sched_wakeup_granularity; + p->se.avg_running = 0; #ifdef CONFIG_SCHEDSTATS p->se.wait_start = 0; @@ -5310,14 +5311,13 @@ static inline void schedule_debug(struct task_struct *prev) #endif } -static void put_prev_task(struct rq *rq, struct task_struct *prev) +static void put_prev_task(struct rq *rq, struct task_struct *p) { - if (prev->state == TASK_RUNNING) { - u64 runtime = prev->se.sum_exec_runtime; + u64 runtime = p->se.sum_exec_runtime - p->se.prev_sum_exec_runtime; - runtime -= prev->se.prev_sum_exec_runtime; - runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost); + update_avg(&p->se.avg_running, runtime); + if (p->state == TASK_RUNNING) { /* * In order to avoid avg_overlap growing stale when we are * indeed overlapping and hence not getting put to sleep, grow @@ -5327,9 +5327,12 @@ static void put_prev_task(struct rq *rq, struct task_struct *prev) * correlates to the amount of cache footprint a task can * build up. */ - update_avg(&prev->se.avg_overlap, runtime); + runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost); + update_avg(&p->se.avg_overlap, runtime); + } else { + update_avg(&p->se.avg_running, 0); } - prev->sched_class->put_prev_task(rq, prev); + p->sched_class->put_prev_task(rq, p); } /* diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 5ddbd08..efb8440 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -395,6 +395,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) PN(se.sum_exec_runtime); PN(se.avg_overlap); PN(se.avg_wakeup); + PN(se.avg_running); nr_switches = p->nvcsw + p->nivcsw; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index c741cd9..3e6f78c 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1605,9 +1605,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ return; } - if (!sched_feat(WAKEUP_PREEMPT)) - return; - if ((sched_feat(WAKEUP_SYNC) && sync) || (sched_feat(WAKEUP_OVERLAP) && (se->avg_overlap < sysctl_sched_migration_cost && @@ -1616,6 +1613,17 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ return; } + if (sched_feat(WAKEUP_RUNNING)) { + if (pse->avg_running < se->avg_running) { + set_next_buddy(pse); + resched_task(curr); + return; + } + } + + if (!sched_feat(WAKEUP_PREEMPT)) + return; + find_matching_se(&se, &pse); BUG_ON(!pse); diff --git a/kernel/sched_features.h b/kernel/sched_features.h index d5059fd..0d94083 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -54,6 +54,11 @@ SCHED_FEAT(WAKEUP_SYNC, 0) SCHED_FEAT(WAKEUP_OVERLAP, 0) /* + * Wakeup preemption towards tasks that run short + */ +SCHED_FEAT(WAKEUP_RUNNING, 0) + +/* * Use the SYNC wakeup hint, pipes and the likes use this to indicate * the remote end is likely to consume the data we just wrote, and * therefore has cache benefit from being placed on the same cpu, see |