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authorDaniel Lezcano <daniel.lezcano@linaro.org>2018-10-04 14:04:03 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-10-25 16:49:27 +0200
commita7fe5190c03f8137ef08db84a58dd4daf2c4785d (patch)
treef4c2935ca4ccb9bbdc113b3bc29bd85c02cd0159 /kernel
parent145d952a29320dea883246bcb24ba1da7ac4bb7f (diff)
downloadlinux-a7fe5190c03f8137ef08db84a58dd4daf2c4785d.tar.bz2
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 372ba8cb46b2 (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] https://android.googlesource.com/kernel/common/+/4dedd9f124703207895777ac6e91dacde0f7cc17 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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9245c56b8f5f..c8d5c279be14 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2887,13 +2887,6 @@ unsigned long nr_iowait_cpu(int cpu)
return atomic_read(&cpu_rq(cpu)->nr_iowait);
}
-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;
-}
-
/*
* IO-wait accounting, and how its mostly bollocks (on SMP).
*