User blog comment:Rappy 4187/Technical Update: July 20, 2016/@comment-26154973-20160721213248/@comment-24473195-20160722185426

As for the inefficiency, it's inefficient because a custom-tailored template hasn't been made for that page yet ... Lua time usage: 3.555s Lua memory usage: 15.56 MB

You probably don't understand what the profiler is for. It is there to help optimize the page, and so only shows up if lua modules are inefficient. An average page with lua takes far less than 200 milliseconds to load. Just because wiki contributors ignored it because it didn't show any errors doesn't change the fact that it was already inefficient before the PHP upgrade. The upgrade just made it visible.

Also note that the time and memory usage is variable, it might be 3 seconds one day, and be 4 or 5 seconds another. That's not counting the normal parsing time. To put it into perspective, if you were using regular templates with no lua, the results would be far worse,  that page would be full of node errors, and also wouldn't load properly.

Perhaps an admin should look at Special:Parserspeed, to see just how bad things are.