CakePHP3 Upgrade Slowness

So I have a backend server application that I am trying to upgrade from CakePHP 2 to CakePHP 3. At the same time we (my team) upgraded PHP to 7.2. After resolving several functional bugs, we did some initial speed testing and found that the system was up to 10 times slower. We invested the time to get New Relic up and running with the new system. Basically, we found that mysql, php, external calls, and response times were all a magnitude slower than our previous system. All areas were slower. We decided to strip down the test to one controller that returns one small string without any database calls or models. We found this call still to be very slow compared to the old system calls that still hit the database and perform logic. We would guess that there is something configured wrong because everything we have learned from others’ experiences would indicate that upgrading to CakePHP3 and PHP 7 would give much faster speeds. Any help or guidance would be greatly appreciated.

Have you tried stripping the test down even further? Tried a static HTML page or a simple PHP page, not running through Cake? Try exiting early from various stages of the Cake bootstrap process to see if you can narrow down where the delay is happening?