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SubjectRe: [RFC v2 0/3][TESTS] LAB: Support for Legacy Application Booster governor - tests results
Hi Viresh,

>
> > On 22 May 2013 15:57, Lukasz Majewski <l.majewski@samsung.com>
> > wrote:
> > >> On 3 May 2013 19:37, Jonghwa Lee <jonghwa3.lee@samsung.com>
> > >> wrote:
> >
> > > I think, that overclocking support is crucial here. As you pointed
> > > out
> > > - ondemand and conservative benefit from it. Therefore, I would
> > > urge for its mainline acceptance.
> > >
> > > (code for reference)
> > > http://thread.gmane.org/gmane.linux.kernel/1484746/match=cpufreq
> > >
> > > In this RFC (patch 1/3), I've decided to put the burden of
> > > overclocking support to platform code (cpufreq/exynos-cpufreq.c
> > > and cpufreq/exynos4x12-cpufreq.c).
> > >
> > > Those changes aren't intrusive for other boards/archs. Moreover
> > > overclocking is closely related to processor clocking/power
> > > dissipation capabilities, so SoC specific code is a good place for
> > > it.
> > >
> > >
> > > What DO need a broad acceptance is the overclocking API proposed
> > > at: include/linux/cpufreq.h
> > >
> > > This introduces interface to which others will be bind. It
> > > shouldn't be difficult to implement overclocking at other SoCs (as
> > > it was proposed for Exynos).
> > >
> > > Feedback is welcome, since I might have overlooked oddities
> > > present at other SoCs.
> >
> > Hi..
> >
> > I am not talking about the minute details here... for example I
> > didn't like the way overclocking support is implemented... It has to
> > be a bit more framework oriented then driver...
> >
> > What I am thinking right now is if it is worth to add both the
> > features you are trying. i.e. overclocking and LAB..
> >
> > So, requested you to give some figures... of ondemand with and
> > without overclocking... Leave LAB for now...

As you wished, I've provided relevant data for overclocking.

Would you be so kind and comment on them?



> >
> > Then we can give LAB a try with above...
>
> Test HW Exynos4412 (4 Cores):
> Kernel 3.8.3
>
> Ondemand max freq: 1.4 GHz
> Overclock max freq: 1.5 GHz
>
>
> Ondemand improvement with and without overclocking (called by us
> TurboBoost - TB):
>
> Dhrystone has been built according to:
> http://zenit.senecac.on.ca/wiki/index.php/Dhrystone_howto
> It's Makefile is also attached.
> ------------------------------------------------
>
> Dhrystone # of Threads
> 1 2 3 4
> ondemand 2054794 2061855 2097902 2090592
> ondemand + TB 2290076 2205882 2281368 2290076
>
> Improvement: 10% 7% 8% 9%
> -------------------------------------------------
>
> Electric charge [C]
> (Avg) [A] * [second] # of Threads
> 1 2 3 4
> ondemand 1,334 1,837 2,296 3,096
> ondemand + TB 1,401 2,2025 2,907 4,34976
>
> Power cost: 5% 17% 21% 29%
> -------------------------------------------------
>
> Execution time [second] # of Threads
> 1 2 3 4
> ondemand 2,827 2,8 2,787 2,872
> ondemand + TB 2,622 2,694 2,667 2,76
>
>
> Speedup: -7% -4% -4% -4%
>
> -------------------------------------------------
>
> "Real life" example:
> time tar -czf linux-3.9.1.tar.gz linux-3.9.1/
>
> Avg current[mA] Time[s]
> Ondemand: 460 153
> Ondemand + TB: 512 144
>
> Result: +10% -6%
>
>
>
> Conclusion:
>
> The main use case for TB is to speed up execution of tasks packed to
> one core. Other cores are then in IDLE state.
>
> For a single core we can safely overclock, since we will not exceed
> its power consumption and thermal limits.
>
>


--
Best regards,

Lukasz Majewski

Samsung R&D Poland (SRPOL) | Linux Platform Group


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