[PATCH v4 0/7] cpufreq:boost: CPU Boost mode support

Lukasz Majewski
2013-06-19T17:13:08Z

This patch series introduces support for CPU overclocking technique
called Boost.

It is a follow up of a LAB governor proposal. Boost is a LAB component:
http://thread.gmane.org/gmane.linux.kernel/1484746/match=cpufreq

Boost unifies hardware based solution (e.g. Intel Nehalem) with
software oriented one (like the one done at Exynos).
For this reason cpufreq/freq_table code has been reorganized to include
common code.

Important design decisions:

- Boost related code is compiled-in unconditionally and disabled by default
The cpufreq_driver is responsibile for setting boost_supported flag and
providing enable_boost callback(if HW support is needed)

- struct cpufreq_driver has been extended with boost related fields:
-- boost_supported - when driver supports boosting
-- enable_boost - callback to function, which is necessary to
enable boost in the processor (like it is done at Intel)

- Boost sysfs attribute (/sys/devices/system/cpu/cpufreq/boost) is always
provided.
It will be read only, until either cpufreq_driver defines boost_supported
flag or device tree's cpufreq "boost_mode" attribute is defined. It is
consistent with legacy acpi API.

- No special spin_lock for Boost was created. The one from cpufreq core
was reused.

- All available policies are now stored in a list.

- The Boost code doesn't rely on any policy. When boost state is changed,
then the policy list is iterated and proper adjustements are done.

- Number of busy cpus (with load > 90%) is calculated and exported as a
global sysfs attribute.

- The SW based boost can be only enabled when up to one core is regarded as
a "busy" one. For safety reasons boost is disabled when more cores comes
into play.

- To improve safety level, the thermal framework is also extended to disable
software boosting, when thermal trip point is reached.

New patches for v4:
cpufreq: Store cpufreq policies in a list
cpufreq: Calculate number of busy CPUs
cpufreq: Enable software boost only when up to one busy core is running
thermal:boost: Disable boost when trip point is reached

Tested at: HW:
Exynos 4412 3.10 linux
Exynos 4210 3.10 linux
Compile tested x86_64 defconfig (acpi) - help with HW (Intel Nehalem) test
needed

Lukasz Majewski (7):
cpufreq: Store cpufreq policies in a list
cpufreq: Add boost frequency support in core
cpufreq:acpi:x86: Adjust the acpi-cpufreq.c code to work with common
boost solution
cpufreq:exynos:Extend Exynos cpufreq driver to support boost
framework
cpufreq: Calculate number of busy CPUs
cpufreq: Enable software boost only when up to one busy core is
running
thermal:boost: Disable boost when trip point is reached

drivers/cpufreq/acpi-cpufreq.c | 61 ++++++-----------
drivers/cpufreq/cpufreq.c | 132 ++++++++++++++++++++++++++++++++++++
drivers/cpufreq/cpufreq_governor.c | 4 ++
drivers/cpufreq/exynos-cpufreq.c | 4 ++
drivers/cpufreq/freq_table.c | 43 ++++++++++--
drivers/thermal/cpu_cooling.c | 3 +
include/linux/cpufreq.h | 15 ++++
7 files changed, 215 insertions(+), 47 deletions(-)

--
1.7.10.4