Created attachment 837180 [details] git bisect log It took only 72 kernels to build and the winner is: commit 244adf6426ee31a83f397b700d964cff12a247d3 Author: Theodore Ts'o <tytso@mit.edu> Date: Thu Jan 23 12:23:17 2020 -0500 ext4: make dioread_nolock the default Reverted that on top of 5.6.6 and the performance is back.