linux/drivers/cpuidle
Arjan van de Ven 1f85f87d4f cpuidle: add a repeating pattern detector to the menu governor
Currently, the menu governor uses the (corrected) next timer as key item
for predicting the idle duration.

It turns out that there are specific cases where this breaks down: There
are cases where we have a very repetitive pattern of idle durations, where
the idle period is pretty much the same, for reasons completely unrelated
to the next timer event.  Examples of such repeating patterns are network
loads with irq mitigation, the mouse moving but in theory also the wifi
beacons.

This patch adds a relatively simple detector for such repeating patterns,
where the standard deviation of the last 8 idle periods is compared to a
threshold.

With this extra predictor in place, measurements show that the DECAY
factor can now be increased (the decaying average will now decay slower)
to get an even more stable result.

[arjan@infradead.org: fix bug identified by Frank]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Corrado Zoccolo <czoccolo@gmail.com>
Cc: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:02 -07:00
..
governors cpuidle: add a repeating pattern detector to the menu governor 2010-05-25 08:07:02 -07:00
cpuidle.c cpuidle: always return with interrupts enabled 2009-10-29 07:39:31 -07:00
cpuidle.h
driver.c
governor.c tree-wide: fix typos "aquire" -> "acquire", "cumsumed" -> "consumed" 2009-11-09 09:40:57 +01:00
Kconfig ACPI: CONFIG_CPU_IDLE=ACPI by default 2007-11-19 22:22:37 -05:00
Makefile
sysfs.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00