On Thu, Mar 8, 2018 at 10:19 AM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote: > On Wed, Mar 7, 2018 at 4:29 PM, Amit Kucheria <amit.kucheria@xxxxxxxxxx> wrote: >> Cpufreq/cpuidle are designed to control a single parameter while >> thermal framework is trying to mitigate heat from several disparate >> sources that are throttled in different ways. Besides, cpufreq/cpuidle >> have somewhat mature governors. Cpuidle has only one governor (for >> tickless) - menu governor, cpufreq has ondemand in mainline, replaced >> by interactive in android and hopefully soon both will be replaced by > > Interactive and schedfreq are already removed from Android 4.4 and 4.9. > It used schedutil now. Good to hear. >> schedutil. >> >> Badly configured cpufreq/cpuidle/devfreq only leads to wasted power, >> while badly configured thermal zone leads to the loss of operation >> e.g. reboots, too hot to touch, etc. > > I don't think such heat-ups will happen right during boot, where some > init.rc should > come up and change the governor. Interestingly enough, there are some patches that make the thermal framework start earlier to deal with boot-time thermal issues. I expect to post them soon. :-) These are required, for example, if the device goes into a reboot loop - the device might not even make it to the point in userspace where the governors are setup. In such a loop, the temperature constantly keeps increasing. > Over that if we are worried about production images only, then what prevents us > to select the right default governor in the defconfig ? We shouldn't > be worried about > multi-platform kernels for production images. I was refering to the 'make defconfig' out-of-box experience that makes the majority of developer boards/devices out there stable to work on. I can't do that today. Regards, Amit -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
