https://drive.google.com/file/d/1Hm9_IIXAL-ig5BfsLnbTxfnmzZR4tTvr/view?usp=drive_linkIn the picture,  the left DMM shows input current and the right DMM shows output voltage. I found the inductor from computer power supply, the inductor works best, when its 20 uH - 25 uH. The switching frequency is around 25khz. 
The comparators are LM393 and i used mosfet driver for fast rise times.
The loss in efficiency is mainly due to oscillations during on time.