Hi, On Monday, June 27, 2016 03:49:44 PM Nicolas Pitre wrote: > On Mon, 27 Jun 2016, Bartlomiej Zolnierkiewicz wrote: > > > Hi, > > > > It seems that in mainline kernel big.LITTLE switcher support > > may be usable only on ARM Versatile Express TC2 platform > > (but even this platform doesn't enable it in its defconfig). > > It is also used on some Samsung targets.
Could you please explain this more? AFAIK mainline never had working IKS solution (big.LITTLE switcher support + arm_big_little CPUfreq driver support) on any Samsung SoC. > > The following patchset removes big.LITTLE switcher support > > (from both ARM core and arm_big_little CPUfreq driver) in > > favor of using HMP. > > > > Since HMP support at scheduler level is not yet merged this > > patchset is probably premature and thus is marked as RFC. > > It is premature indeed. > > And before this is removed, comparison with power/performance benchmark > numbers will have to be provided as well to justify this removal. At > the moment there is nothing else in mainline that can achieve what this > code does. I agree given that this code has real users and according to my research on mainline kernel it seems that the IKS functionality (bL switcher core code together with arm_bit_little CPUfreq driver support) is usable only on TC2 and even this platform doesn't enable it by default. IOW I would really like to get the confirmation that there are platforms that are making use of IKS functionality currently with the mainline kernel. Otherwise we should either consider its removal or enable it on platforms that are supposed to use it. > We all agree that the scheduler based solution is the best way to do it. > But this has been a couple years already and this is still work in > progress. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
