ActionDispatch::Routing::RouteSet#call Rails 4.1 really slow

Question

I\'ve searched for days but can\'t find any relevant answers to this question.

In my Rails 4.1 app hosted on Heroku, when the load goes up, some PUT requests get REA

Answer 1

You could use rack-mini-profiler to check where the real problem is.

Answer 2

The slowdown is an indicator that it's Heroku-specific. Probably why you saw the problem disappear when you upgraded to Performance Dynos.