linux/kernel/sched
Daniel Lezcano a7fe5190c0 cpuidle: menu: Remove get_loadavg() from the performance multiplier
The function get_loadavg() returns almost always zero. To be more
precise, statistically speaking for a total of 1023379 times passing
in the function, the load is equal to zero 1020728 times, greater than
100, 610 times, the remaining is between 0 and 5.

In 2011, the get_loadavg() was removed from the Android tree because
of the above [1]. At this time, the load was:

unsigned long this_cpu_load(void)
{
        struct rq *this = this_rq();
        return this->cpu_load[0];
}

In 2014, the code was changed by commit 372ba8cb46 (cpuidle: menu: Lookup CPU
runqueues less) and the load is:

void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
{
        struct rq *rq = this_rq();
        *nr_waiters = atomic_read(&rq->nr_iowait);
        *load = rq->load.weight;
}

with the same result.

Both measurements show using the load in this code path does no matter
anymore. Removing it.

[1] 4dedd9f124

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-25 16:49:27 +02:00
..
autogroup.c sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] 2018-05-05 08:34:42 +02:00
autogroup.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
clock.c sched/clock: Disable interrupts when calling generic_sched_clock_init() 2018-07-30 19:33:35 +02:00
completion.c sched/Documentation: Update wake_up() & co. memory-barrier guarantees 2018-07-17 09:30:34 +02:00
core.c cpuidle: menu: Remove get_loadavg() from the performance multiplier 2018-10-25 16:49:27 +02:00
cpuacct.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpudeadline.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpudeadline.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpufreq_schedutil.c sched/fair: Remove #ifdefs from scale_rt_capacity() 2018-07-25 11:41:05 +02:00
cpufreq.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpupri.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpupri.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cputime.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
deadline.c sched/numa: Pass destination CPU as a parameter to migrate_task_rq 2018-10-02 09:42:21 +02:00
debug.c sched/debug: Fix potential deadlock when writing to sched_features 2018-09-10 10:13:45 +02:00
fair.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 15:00:03 +01:00
features.h sched/fair: Disable LB_BIAS by default 2018-10-02 09:45:01 +02:00
idle.c x86/stackprotector: Remove the call to boot_init_stack_canary() from cpu_startup_entry() 2018-10-22 04:07:24 +02:00
isolation.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
loadavg.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
Makefile sched/pelt: Move PELT related code in a dedicated file 2018-07-15 23:51:20 +02:00
membarrier.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
pelt.c sched/fair: Remove setting task's se->runnable_weight during PELT update 2018-10-02 09:45:03 +02:00
pelt.h sched/pelt: Fix warning and clean up IRQ PELT config 2018-10-02 09:45:00 +02:00
rt.c Merge branch 'sched/urgent' into sched/core, to pick up fixes 2018-07-25 11:29:58 +02:00
sched-pelt.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sched.h Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:05:28 +01:00
stats.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
stats.h sched: Clean up and harmonize the coding style of the scheduler code base 2018-03-03 15:50:21 +01:00
stop_task.c sched: Clean up and harmonize the coding style of the scheduler code base 2018-03-03 15:50:21 +01:00
swait.c sched/swait: Rename to exclusive 2018-06-20 11:35:56 +02:00
topology.c sched/topology: Make local variables static 2018-09-10 15:10:57 +02:00
wait_bit.c sched/wait: Improve __var_waitqueue() code generation 2018-03-20 08:23:25 +01:00
wait.c sched/wait: assert the wait_queue_head lock is held in __wake_up_common 2018-08-22 10:52:47 -07:00