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author | Peter Zijlstra <peterz@infradead.org> | 2019-11-08 14:15:57 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2019-11-11 08:35:19 +0100 |
commit | 5d7d605642b28a5911198a405a6072f091bfbee6 (patch) | |
tree | 106be03c550adf9a7fdef6688542e4ee66c03887 /kernel/sched/sched.h | |
parent | f488e1057bb97b881ed317557dc5e62ff8747393 (diff) | |
download | linux-5d7d605642b28a5911198a405a6072f091bfbee6.tar.gz linux-5d7d605642b28a5911198a405a6072f091bfbee6.tar.bz2 linux-5d7d605642b28a5911198a405a6072f091bfbee6.zip |
sched/core: Optimize pick_next_task()
Ever since we moved the sched_class definitions into their own files,
the constant expression {fair,idle}_sched_class.pick_next_task() is
not in fact a compile time constant anymore and results in an indirect
call (barring LTO).
Fix that by exposing pick_next_task_{fair,idle}() directly, this gets
rid of the indirect call (and RETPOLINE) on the fast path.
Also remove the unlikely() from the idle case, it is in fact /the/ way
we select idle -- and that is a very common thing to do.
Performance for will-it-scale/sched_yield improves by 2% (as reported
by 0-day).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: ktkhai@virtuozzo.com
Cc: mgorman@suse.de
Cc: qais.yousef@arm.com
Cc: qperret@google.com
Cc: rostedt@goodmis.org
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20191108131909.603037345@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/sched.h')
-rw-r--r-- | kernel/sched/sched.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c8870c5bd7df..66172a337675 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1821,6 +1821,9 @@ static inline bool sched_fair_runnable(struct rq *rq) return rq->cfs.nr_running > 0; } +extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf); +extern struct task_struct *pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf); + #ifdef CONFIG_SMP extern void update_group_capacity(struct sched_domain *sd, int cpu); |