I would like to change the value of dirty_writeback_centisecs. After seeing the Tunables in Powertop, there seems to be a problem with the value which is 6000 which is considered to be bad by Powertop. It echoes the value to 1500. However, the change is not persistent.
vm.dirty_writeback_centisecs=1500 in the /etc/sysctl.conf
sys.vm.dirty_writeback_centisecs=1500 neither did work. Also, in /etc/sysctl.d/99-sysctl.conf which too didn't work.
The value is still 6000 on restart.