kernel_optimize_test/drivers/cpuidle
Rafael J. Wysocki 159e48560f cpuidle: teo: Fix "early hits" handling for disabled idle states
The TEO governor uses idle duration "bins" defined in accordance with
the CPU idle states table provided by the driver, so that each "bin"
covers the idle duration range between the target residency of the
idle state corresponding to it and the target residency of the closest
deeper idle state.  The governor collects statistics for each bin
regardless of whether or not the idle state corresponding to it is
currently enabled.

In particular, the "early hits" metric measures the likelihood of a
situation in which the idle duration measured after wakeup falls into
to given bin, but the time till the next timer (sleep length) falls
into a bin corresponding to one of the deeper idle states.  It is
used when the "hits" and "misses" metrics indicate that the state
"matching" the sleep length should not be selected, so that the state
with the maximum "early hits" value is selected instead of it.

If the idle state corresponding to the given bin is disabled, it
cannot be selected and if it turns out to be the one that should be
selected, a shallower idle state needs to be used instead of it.
Nevertheless, the metrics collected for the bin corresponding to it
are still valid and need to be taken into account as though that
state had not been disabled.

As far as the "early hits" metric is concerned, teo_select() tries to
take disabled states into account, but the state index corresponding
to the maximum "early hits" value computed by it may be incorrect.
Namely, it always uses the index of the previous maximum "early hits"
state then, but there may be enabled idle states closer to the
disabled one in question.  In particular, if the current candidate
state (whose index is the idx value) is closer to the disabled one
and the "early hits" value of the disabled state is greater than the
current maximum, the index of the current candidate state (idx)
should replace the "maximum early hits state" index.

Modify the code to handle that case correctly.

Fixes: b26bf6ab71 ("cpuidle: New timer events oriented governor for tickless systems")
Reported-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
2019-10-14 10:40:33 +02:00
..
governors cpuidle: teo: Fix "early hits" handling for disabled idle states 2019-10-14 10:40:33 +02:00
coupled.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
cpuidle-arm.c ARM: cpuidle: Remove overzealous error logging 2019-08-09 17:51:39 +01:00
cpuidle-at91.c drivers/cpuidle: Convert non-modular drivers to use builtin_platform_driver 2015-06-16 14:12:38 -04:00
cpuidle-big_little.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cpuidle-calxeda.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
cpuidle-clps711x.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpuidle-cps.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpuidle-exynos.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cpuidle-haltpoll.c cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available 2019-09-11 17:46:15 +02:00
cpuidle-kirkwood.c ARM: cpuidle: Remove duplicate header inclusion 2015-03-23 18:03:11 +01:00
cpuidle-mvebu-v7.c cpuidle: mvebu: disable the bind/unbind attributes and use builtin_platform_driver 2015-10-23 12:40:48 +02:00
cpuidle-powernv.c powernv/cpuidle: Use parsed device tree values for cpuidle_init 2018-07-31 19:56:44 +10:00
cpuidle-psci.c PSCI: cpuidle: Refactor CPU suspend power_state parameter handling 2019-08-09 17:51:39 +01:00
cpuidle-pseries.c powerpc/pseries/cpuidle: Fix preempt warning 2018-12-04 19:45:01 +11:00
cpuidle-ux500.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cpuidle-zynq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
cpuidle.c cpuidle: add poll_limit_ns to cpuidle_device structure 2019-07-30 17:27:37 +02:00
cpuidle.h cpuidle: allow governor switch on cpuidle_register_driver() 2019-09-11 17:36:30 +02:00
driver.c cpuidle: allow governor switch on cpuidle_register_driver() 2019-09-11 17:36:30 +02:00
dt_idle_states.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
dt_idle_states.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
governor.c cpuidle: allow governor switch on cpuidle_register_driver() 2019-09-11 17:36:30 +02:00
Kconfig cpuidle: add haltpoll governor 2019-07-30 17:27:37 +02:00
Kconfig.arm ARM: psci: cpuidle: Enable PSCI CPUidle driver 2019-08-09 17:51:39 +01:00
Kconfig.mips treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.powerpc treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile Power management updates for 5.4-rc1 2019-09-17 19:15:14 -07:00
poll_state.c cpuidle: add poll_limit_ns to cpuidle_device structure 2019-07-30 17:27:37 +02:00
sysfs.c cpuidle: add poll_limit_ns to cpuidle_device structure 2019-07-30 17:27:37 +02:00