Hi Viresh, > > > On 22 May 2013 15:57, Lukasz Majewski <l.majewski@xxxxxxxxxxx> > > wrote: > > >> On 3 May 2013 19:37, Jonghwa Lee <jonghwa3.lee@xxxxxxxxxxx> > > >> 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 -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
