ANBZ: #22143
In high-concurrency scenarios, highclass tasks often select the same
idle CPU when waking up, which can cause scheduling delays. The reason
is that To reduce
the scheduling delays caused by this situation, we introduce
ID_BOOK_CPU:
When highclass task selecting idle cpu, check whether it has been
booked by other tasks and whether it's still idle before we select it
to wake up. If the idle cpu we found has been booked by other tasks,
select again, until book the idle cpu successfully or reach the retry
limit. If the idle cpu hasn't been booked by any other, make rq->booked
true to mark that the cpu is booked, and make rq->booked false after the
highclass task actually enqueues into the rq of the cpu.
To Enable ID_BOOK_CPU,
echo ID_BOOK_CPU > /sys/kernel/debug/sched_features.
To set retry limit, modify /proc/sys/kernel/sched_id_book_cpu_nr_tries.
Signed-off-by: Cruz Zhao <CruzZhao@linux.alibaba.com>
Reviewed-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Link: https://gitee.com/anolis/cloud-kernel/pulls/5455
ad071c796e