cpufreq/cpufreq_intellidemand: intellidemand cpufreq governor (version 3.1)

Intellidemand is inspired by ondemand governor. Its main features are:

 - auto cpu hotplugging based on runnable thread average calculations
 - detection of browsing mode (long screen on activities with moderate run
   queue depth =< 38 )
 - limit max frequencies when in browsing mode to conserve battery for long
   duration tasks

Browsing State Determination:
 1- Browsing state is enabled as power-on default. Browsing state is disabled
    when run queue depth is > 38 for 2 consecutive samples
    (very high instantaneous spikes)

Browsing State Limit Max Freq Logic (sliding window algorithm):
 1- While Screen is ON > 3 min, and average load of the CPU is < 35%, then
    CPU Max frequencies will remain power-on default
 2- While Screen is On, if average CPU load > 35%, both CPUs max frequencies
    will be limited to a lower user configurable max value
 3- While Screen is On, After both CPUs' Max is limited to lowered max, when
    the average CPU load has dropped down to less than < 25%, then both CPUs
    Max freq will be restored to back to power-on default

Runnable Thread Auto-hotplug (fast hotplug / slow unplug algorithm):
 1- When average number of running thread is < threshold, 2nd cpu will be
    unplugged.
 2- When > threshold, 2nd cpu will be hotplugged.
 3- The logic applies a fast hotplug and slow unplug algorithm so 2nd core
    will stay enabled longer to help deal with performance spikes

changes from Ver 3.0 -> Ver 3.1:
  - add run queue persistence to better determine browsing state
changes from Ver 2.0 -> Ver 3.0:
  - remove GPU Busy dependency for browsing state detection (this will make
    the governor more portable to other platforms without specific GPU
    architecture knowledge)

dependencies:
  -- Qualcomm's run queue average logic (SOC independent logic)
  -- TI's runnable thread average logic (SOC independent logic)

adapted for OMAP2 platform

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/mach-omap2/board-tuna.c
	arch/arm/mach-omap2/omap2plus-cpufreq.c
	drivers/cpufreq/Kconfig
	drivers/cpufreq/Makefile
	include/linux/cpufreq.h
intellidemand: Add boost pulse capability

Boost pulse increases UI performance by increasing CPU freq and
reduce sampling time.

Signed-off-by: Paul Reioux <reioux@gmail.com>
intellidemand: add bug fixes

 - Fix crash input event handler on governor switch
 - Fix panic when setting sampling rate

Signed-off-by: Paul Reioux <reioux@gmail.com>
intellidemand: increase nr_run_threshold back to 5 with PowerHAL available
intellidemand: tweak for better UI and Battery performance
intellidemand: add a run queue persistence to determine browsing state

persistence will allow for better browsing state detection rather than just
purely based on run queue depth alone

Signed-off-by: Paul Reioux <reioux@gmail.com>
intellidemand: WIP tweaks
intellidemand: add minimum cpu performance lock

a minimum cpu frequency performance lock is add to ensure smooth
operations when only 1 core is active

Signed-off-by: Paul Reioux <reioux@gmail.com>
wip: intellidemand tweaks
intellidemand: wip tweak
wip: intellidemand tweaks
wip: intellidemand tweaks
wip: intellidemand tweak avg from 5 to 7
intellidemand: tweaked hysteresis value for better UI response

Signed-off-by: faux123 <reioux@gmail.com>
intellidemand: Add support to consider other cpu load when scaling frequencies

Currently only current cpu load is considered when frequency scaling.
As a side effect of this when scheduler migrates a thread to a slower
core, the execution time increases unexpectedly.

The new algorithm not only considers current cpu load for frequency
scaling, but also takes into account load of other online cpus. The
treshold for this can be controlled using up_threshold_any_cpu_load.
When the up_threshold_any_cpu_load is crossed in any cpu then the
current cpu is set to sync_freq.

Also, when more than one cpu is online a two step ramp-up mechanism
is used. When the up_threshold_multi_core is crossed the cpu is ramped
up to optimal_freq which is less than policy->max and set to a power
friendly value.

Change-Id: I64bed1b142cde1f239e73aa1f78981c78aaf59ce
Signed-off-by: Narayanan Gopalakrishnan <nargop@codeaurora.org>

intellidemand: Fix kernel warning in cpufreq_governor_dbs
GOV_STOP event destroys the timer_mutex and is not initialized back
upon GOV_START event.

The Kernel complains at mutex_lock(during GOV_LIMITS event) after
mutex_destroy.

[<c0014918>] (unwind_backtrace+0x0/0x11c)
[<c007c004>] (warn_slowpath_common+0x4c/0x64)
[<c007c034>] (warn_slowpath_null+0x18/0x1c)
[<c079eef8>] (__mutex_lock_slowpath+0x130/0x3c4)
[<c079f1ac>] (mutex_lock+0x20/0x3c) from [<c0540900>]
[<c0540900>] (cpufreq_governor_dbs+0x3c8/0x468)
[<c053d500>] (__cpufreq_governor+0x90/0xe0)
[<c053d774>] (__cpufreq_set_policy+0x224/0x258)
[<c053da58>] (cpufreq_add_dev_interface+0x2b0/0x308)
[<c053e784>] (cpufreq_add_dev+0x500/0x56c)
[<c079247c>] (cpufreq_cpu_callback+0x88/0x9c)
[<c07a2ca8>] (notifier_call_chain+0x38/0x68)
[<c007ded0>] (__cpu_notify+0x28/0x40)
[<c0790024>] (_cpu_up+0xe4/0x118)
[<c0790024>] (cpu_up+0x64/0x80)
[<c0765840>] (store_online+0x48/0x78)
[<c038d0c8>] (dev_attr_store+0x18/0x24)
[<c017be40>] (sysfs_write_file+0x108/0x13c)
[<c012cdfc>] (vfs_write+0xb0/0x128)
[<c012d034>](sys_write+0x38/0x64)

Change-Id: Ie2a796b17209243de731ccf2ab04b7f9e7048df8
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>
Adapted for Intellidemand from CAF reference

Signed-off-by: faux123 <reioux@gmail.com>
intellidemand: give intellidemand's cpu_dbs_info its own name

Signed-off-by: faux123 <reioux@gmail.com>
intellidemand: add default values for dbs sync and optimal tuneables

Signed-off-by: faux123 <reioux@gmail.com>
cpufreq/intellidemand: make some tunables static instead of global scope

Signed-off-by: faux123 <reioux@gmail.com>
rq_stats: add run queue statistic collection to kernel tick scheduler

adapted from CAF reference for OMAP2 Platform

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/mach-omap2/Kconfig
	arch/arm/mach-omap2/Makefile
	kernel/time/tick-sched.c
cpufreq: Add cpu utilization statistics to aid decisions made by userspace.

Understanding system load as seen by cpufreq can help userspace
algorithms make better decisions to improve system responsiveness.
One such example would be the MP decision algorithm which mines
various system info to make decisions on hotplugging in/out
the additional cores.

Change-Id: I277db7e1a7803a3822b61e7befa25131487cfe17
Signed-off-by: Anitha Anand <anithas@codeaurora.org>