/system/bin/logd seems to be a bit of a CPU/battery hog, and cannot be killed or paused, so here is how to disable it:

Either in twrp or rooted android, connect to adb shell. Then:

CODE

cd /mnt
mkdir linux
mount /dev/block/mmcblk0p29 linux
mkdir system
mount linux/data/system.img system
mv system/bin/logd system/bin/logd.bak


(Tried and failed to mount system.img as rw under debian, if anyone knows how to do that it would make the process much easier!)