cpuidle: fix comment

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: "tuukka.tikkanen@linaro.org" <tuukka.tikkanen@linaro.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: menu governor - remove unused macro STDDEV_THRESH

STDDEV_THRESH was once defined and used in menu governor. But now its no longer
used anywhere. So removing the define.

Signed-off-by: Mohammad Merajul Islam Molla <meraj.enigma@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: ladder governor - use macro instead of hardcoded value

use CPUIDLE_DRIVER_STATE_START, instead of hardcoded value 0. As,
CPUIDLE_DRIVER_STATE_START can be 1/0 based on
CONFIG_ARCH_HAS_CPU_RELAX is defined or not.

Signed-off-by: Mohammad Merajul Islam Molla <meraj.enigma@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: menu: Use shifts when calculating averages where possible

We use do_div even though the divisor will usually be a power-of-two
unless there are unusual outliers. Use shifts where possible

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: menu: Use ktime_to_us instead of reinventing the wheel

The ktime_to_us implementation is slightly better than the one implemented
in menu.c. Use it

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle: menu: Call nr_iowait_cpu less times

menu_select() via inline functions calls nr_iowait_cpu() twice as much
as necessary.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
cpuidle / menu: move repeated correction factor check to init

In menu_select function we check for correction factor every time.
If it is zero we are initializing to unity. Hence move it to init function
and initialise by unity, hence avoid repeated comparisons.

Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
Reviewed-by: Tuukka Tikkanen <tuukka.tikkanen@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>