I've just created a new (empty) Mediawiki installation on php7.0 in docker. I'm using Ubuntu 16.04 and a MySQL instance from Amazon's RDS. The wiki is very slow. It takes around 5 seconds to load any page. It takes around 8 seconds to write to a page.
What am I doing wrong? I have the default LocalSettings.php that was generated by the installation process. I've tried setting apache trace8, monitoring DNS via tcpdump, also using mediawiki debug. I cannot see what's taking the time, all processes just seem slow.