Re: [PATCH v6 0/8] cpufreq:boost: CPU Boost mode support

From: Viresh Kumar
Date: Fri Jul 26 2013 - 06:28:54 EST


On 25 July 2013 22:03, Lukasz Majewski <l.majewski@xxxxxxxxxxx> wrote:
> 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 to cpufreq core and
> disabled by default. The cpufreq_driver is responsibile for setting
> boost_supported flag and providing set_boost callback(if HW support
> is needed). For software managed boost, special Kconfig flag -
> CONFIG_CPU_FREQ_BOOST_SW has been defined. It will be selected only
> when a target platform has thermal framework properly configured.
>
> - struct cpufreq_driver has been extended with boost related fields:
> -- boost_supported - when driver supports boosting
> -- boost_enabled - boost state
> -- set_boost - callback to function, which is necessary to
> enable/disable boost
>
> - Boost sysfs attribute (/sys/devices/system/cpu/cpufreq/boost) is visible
> _only_ when cpufreq driver supports Boost.
>
> - 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.
>
> - To improve safety level, the thermal framework is also extended to disable
> software boosting, when thermal trip point is reached. Then it starts
> monitoring target temperature to evaluate if boost can be enabled
> again. This emulates behaviour similar to HW managed boost (like x86)
>
> New patches for v6:
> cpufreq:exynos4x12: Change L0 driver data to CPUFREQ_BOOST_FREQ
>
> Tested at HW:
> Exynos 4412 3.11-rc1 Linux
> Intel Core i7-3770 3.11-rc1 Linux

I am done with review of this patchset now and should say pretty much
comfortable with it now..
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