Plack is a performance booster for Perl web applications. Plack can enhance the speed of Koha while various operations. Plack requires Apache 2.4.10+ and can enable with Koha installed in Debian 8 (Jessie) / Ubuntu 16.04 LTS.
Apply following commands after the installation of Koha:
sudo koha-plack --enable library
sudo koha-plack --start library
sudo service apache2 restart
Note: Plack creates cache for speed. Make sure the PC has good amount of RAM, if you are going to enable Plack.