Hoppers are using way too much CPU and it goes worse in 1.12.2 as you can see in timings(photos) hoppers started to use more CPU(doubled). Also all of these are caused by 800 hoppers.
We were 1.12.1 and was getting a high tps(20) but we upgraded to 1.12.2, ironically hoppers started to use more CPU and tps been 10 we didn't change the hopper count tho. We tought that maybe this happened because of update and downgraded to 1.12.1 back as expected tps went to 20 back. You can see the timings as proof.