Am Mittwoch, 2. Dezember 2015 03:49:02 UTC+1 schrieb Siarhei Siamashka: > A rather popular problem reported by new users on irc is very > laggy performance out of the box. The default ondemand governor > is too slow to react on increased demand for processing power > without extra tuning. This extra tuning needs extra efforts > from the users and prior knowledge that such tuning might be > necessary. > > The most important defconfigs are sun4i_defconfig, sun5i_defconfig > and sun7i_defconfig because they are mentioned in > http://linux-sunxi.org/Linux_Kernel#Compilation > > This patch changes defconfigs to have the following set of governors: > 1. 'performance' (default) > 2. 'userspace' (for benchmarking purposes) > 3. 'interactive' (a replacement for 'ondemand' with more sane > default behavior) > > One more reason not to use the 'ondemand' governor by default is > that the power saving provided by it is not particularly good: > https://www.mail-archive.com/linux-sunxi@googlegroups.com/msg00492.html > https://www.mail-archive.com/linux-sunxi@googlegroups.com/msg00678.html > http://www.cubieforums.com/index.php/topic,1413.msg8745.html#msg8745 > > It basically wastes a lot of performance for almost nothing. > > Signed-off-by: Siarhei Siamashka <siarhei.siamas...@gmail.com>
I don't think this is good or coherent solution. 1) If the performance governor is the default, it means that a lot of boards will run constantly at overvolted out-of-spec settings by default. Now, I haven't heard of any issues with boards running at 1.425 or 1.45 volts. Nevertheless, we don't allow that in mainline by default either, so I don't think that change is consistant. With the ondemand governor, the CPU may still use these dvfs settings, but at least it will clock down if there's no load. 2) If the ondemand governor behaves too sluggish on lower frequencies, I think the logical solution would be to clean up those dvfs tables and remove these very low frequencies rather than changing the governor so it won't clock down anymore. Personally, I use 384MHz as minimum frequency on my A20 boards, just to give one example. 3) If the interactive governor performs better than ondemand, why not make it the default? 4) Did you test the impact on the SoC temperature when running at maximum frequency instead of clocking up and down ondemand? That being said, I wouldn't bother much with this patch still being applied since I'm not using linux-sunxi-3.4 anymore. Regards, Timo -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
