[Xiaomi Mi 4C] a5m:
We can take a stock thermal config as a starting point. If we do not have any issues, there is no need to change it. But if we do, there are several directions to change it:

Is it uncomfortably hot in everyday use? We can turn off big cluster earlier or/and increase or prolong throttling.

Our game became sluggish when the device is getting hotter? There are two points where it can happen:

Big cores are off (45°). This means the game is really heavy and relies on big cores. We can postpone switching off the cores, however, without throttling under heavy load it is a matter of minutes to reach really hot temperatures. Therefore, we should prolong throttling.

Little cluster is throttled to unusable 600 MHz (49°). If we noticed the problem only now, this means our game is not so heavy, so it can work perfectly on the little cores alone. The solution is to restrict the throttling to something sensible (like 864-960 MHz) as I never so such a great throttling on other devices. Then you can turn off the big cores earlier to postpone reaching the threshold for the little cores.

I've updated my AROMA-installer of thermal-configs with English (or rather Runglish...) translation.

It seems one cannot download files from 4pda.ru without registration, so I am attaching it here. Though this starts to look as an offtopic. I hope solis_f will forgive me.

View attachment a5m_thermal-engine_170405.zip

Screenshots:

Source: http://4pda.ru/forum/index.php?showtopic=707426&view=findpost&p=52348564

UPD:

And here is my AROMA-installer for custom init.qcom.post_boot.sh scripts. Google Drive link.

Source: http://4pda.ru/forum/index.php?showtopic=707426&view=findpost&p=54194522

I'm a bit skeptical about this "completed sooner" thing. It may be a case sometimes, but, in general, I see many applications would eat any frequency you throw at them and will not choke, or otherwise this "sooner" will not be enough to influence the battery savings in general. Why not to keep frequencies at their maxs all the time then? I mean if it will really make things completed sooner and then CPU can cool down and save more battery, then we should set its governor to "performance" (always on max). I believe the thought behind using higher minimal frequencies than available is that it does not matter much — both are considered "low enough". Actually, I experimented with setting the governor for little cores to "performance". I've got around 1 hour less of SOT with my scenarios. Why? When there is a load, it may not matter very much if it is "performance" or "interactive". When there is no load or the load is small, the battery drain is again not overly different for little cores. We are not comparing here 384 vs 1440, but dynamic 384-1440 vs fixed 1440, so the difference can be...really different depending on scenarios.

And don't forget about the thermal-engine. I made my customs scripts mostly with temperature in mind as I find battery savings are not so great. Even if you cut off the big cores completely and cut little cores to, let's say 864 MHz, it will not give you more than ~1 hour of SOT if any (except you are a heavy user), comparing to some sensible config utilizing all the frequencies. You would have to charge the phone as usual, but suffer from its low performance.