On Fri, 28 Jun 2013 09:20:40 +0530, Viresh Kumar wrote: > On 27 June 2013 20:12, Lukasz Majewski <l.majew...@samsung.com> wrote: > > On Thu, 27 Jun 2013 16:46:44 +0530, Viresh Kumar wrote: > >> @Rafael: We need you to jump into this discussion now, I don't > >> have a good idea about what we should do :) > >> > >> On 27 June 2013 16:28, Lukasz Majewski <l.majew...@samsung.com> > >> wrote: > >> > Do you have any idea of how to precisely set the load threshold? > >> > >> I thought we are talking about cpu being in idle state. > > > > If we _drop_ the idea with thermal subsystem to disable the boost, > > the logic as far as I've understood shall here be as follow: > > > > Only enable BOOST when one CPU load > THRESHOLD_MAX and other CPUs < > > THRESHOLD_MIN > > Again, I thought that we are talking about cpus being completely idle. > i.e. in WFI (wait for interrupt) or deeper states. > > > THRESHOLD_MIN & THRESHOLD_MAX are SoC specific. > > > > In my opinion the above constrain imposes policy to the cpufreq > > driver. > > Hmm. > > > So thermal or "other solution" [*] shall disable boost when > > overheated and enable it back when things cool down. > > yeah..
For me thermal is a good candidate to enable boost again. I only need to find a proper place for it. > > > [*] @ Viresh & Rafael do you have any idea about the "other > > solution" here? > > Not really sure :) Not any single one? Then I would like to propose thermal. > > >> There might be platforms where overheating isn't a issue with > >> boost, if it is only enabled while only one cpu is in use. > > > > Could you elaborate more on this? > > I meant platforms where chip doesn't heat up much when only one core > is in use and is using boost frequency. So, they may not require > support for thermal layer at all.. But I am not aware of what the > ground reality is. If such systems can be possible or not. Ok. > > > This would prevent situation when somebody made a mistake and > > had enabled boost, but for some reason had forgotten to > > configure/enable thermal subsystem. > > > > Moreover Kconfig's CONFIG_CPUFREQ_BOOST flag would indicate that > > user enabled boost for some reason and he/she (presumably) knows > > what is doing. > > Yeah.. And drivers like ACPI cpufreq and exynos can simply do a select > from their Kconfig entries so that user isn't required to select them. Automatic select is not a good option. My goal would be here to define BOOST as NO by default (at lease for SW managed ones). And allow user to enable it explicitly. -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
