[Xperia Z5 General] RyTekk:
I intended to delete thermal engine to unlock the maximum performance of S810, but I didn't after a half day for thinking. Then I took a look at thermal-engine and do some optimize for it.

When I looked at the thermal-engine, I saw it use emmc_therm (temperature of emmc) sensor to do throttle, and the throttle start too soon, from 43°C, detail is two cores 6 and 7 will be hotplug (plug out, turn off), and big cluster will be limited to 1.2GHz at just 47.7°C (the battery temperature is just ~40-41°C). You can see more detail in below:

Temperature (/1000 to get the values in Celcius):

43000

47700

48900

50200

51400

52000

52600

53200

53600

54000

54500

55000

55500

55900

56300

56800

Action: cluster0+cluster1+hotplug_4+hotplug_5+hotplug_6+hotplug_7+gpu+s_backlight+battery+modem+s_cam_ltb_tim+s_cam+s_tel

1555200+1958400+0+0+1+1+630000000+255+2+0+100000+0+0

1555200+1248000+0+0+1+1+630000000+209+3+0+100000+0+0

1478400+864000+0+1+1+1+630000000+171+3+0+100000+0+0

1478400+384000+1+1+1+1+630000000+141+3+0+100000+0+0

1344000+384000+1+1+1+1+630000000+115+3+0+100000+0+0

1344000+384000+1+1+1+1+630000000+95+3+0+100000+0+0

1248000+384000+1+1+1+1+630000000+78+8+0+100000+0+0

1248000+384000+1+1+1+1+630000000+64+8+0+001800+0+0

960000+384000+1+1+1+1+630000000+52+9+0+001800+0+0

960000+384000+1+1+1+1+450000000+44+12+0+001800+0+0

864000+384000+1+1+1+1+450000000+44+12+0+001800+0+0

864000+384000+1+1+1+1+390000000+44+12+1+001800+0+0

768000+384000+1+1+1+1+390000000+44+12+1+001800+0+0

600000+384000+1+1+1+1+180000000+44+12+1+001800+0+0

460800+384000+1+1+1+1+180000000+44+12+1+001800+0+0

384000+384000+1+1+1+1+180000000+44+12+1+001800+5+0

EXPLAIN (from my knowledge, maybe it's not right at all)

cluster0: LITTLE (A53 cores) cluster clock limitation, value: hertz

cluster1: big (A57 cores) cluster clock limitation, value: hertz

hotplug_4-7: 1 to hotplug (disable) the core, 0 to do nothing.

gpu: GPU frequency, value: hertz (?)

s_backlight: the maximum brightness of screen, range: 255-0

modem: 1 to disable mobile data, 0 to do nothing.

the rest: IDK

I did a quick research and found that emmc can work from -25°C to +85C, so the limitation that Sony has set is too low (for me), just do a Geekbench and then the performance will come down clearly. Then I edit thermal-engine to increase the maximum performance of S810 but still keep my phone (IDK about yours just because we're not the same) in peace.

So why do I post here? Firstly, for those who wanna take the risk like me to unlock/get the true performance of our devices; secondly, maybe my knowledge is not right so I want you who have certain knowledge about this (EMMC, battery limitation; thermal, blah blah blah) correct me and help me and other users improve it.

I've done attached two files, one is original and the other is mine, hope you guys (who are sensei) will take a look on it to contribute for the community. For those who wanna use them, backup thermal-engine.conf first in /system/etc then copy the modify to the direction, correct name and permission and reboot.

UPDATE:

Thanks to @Envious_Data, his guide helped me to manage big cluster, now I can turn 4 big cores always on by make them becomes "non big cores", so now our phones are true octa cores. I was afraid that there're some issues that will appear such as heating, throttle (thermal manage won't work correct if it recognizes big cluster to be little cluster) so I made a test with Antutu Stress test and monitor CPU cores via Trepn Profiler, and amazing, thermel engine still works fine and my phone's temperature isn't different from old/original settings (just 1 big core on time and will be plugged in if need) so far (of course it should be hotter but not much). And I updated new thermal values too to improve some performance in camera. About battery life, I guess it would not go so far from stock settings because I saw the current discharge (mA) isn't higher (a lot).

Update 17/06: re-setting back to big cores for the best compatibility after enable all 4 big cores, so true octa cores is still there with big core setting is 1 (true).

Update 23/06: new thermal-engine to adapt with OC from SunKernel, it still works fine with stock or even any different maximum clock speed in kernel, why? Because I simply just remove "clusterX" action instead of edit it to match with the maximum clock.

INSTALL: download MODIFY files and rename to init.qcom.post_boot.sh and thermal-engine.conf (due to XDA's restriction so I have to change their type), put in /system/etc/, correct permission (644 rw-r--r--) and reboot.

UPDATING... (depend on you)