I just popped off a branch of my production Rails 4.1.8 app (Can't quite do 4.2 yet), and upgraded it 2 Ruby 2.2. I ran 271 spec against it 5 times before the upgrade and 16 times after. I should have done more before :(
For 2.1.5
AVG: 18.02
MEDIAN: 18.11
MIN: 16.26
MAX: 19.6
For 2.2
AVG: 18.162~
MEDIAN: 15.23
MIN: 14.44 <- nice
MAX: 47.03 <- first run, wut?
It looks better, but I haven't profiled the app on Passenger yet to see how well it plays with the whole app.
For 2.1.5
AVG: 18.02
MEDIAN: 18.11
MIN: 16.26
MAX: 19.6
For 2.2
AVG: 18.162~
MEDIAN: 15.23
MIN: 14.44 <- nice
MAX: 47.03 <- first run, wut?
It looks better, but I haven't profiled the app on Passenger yet to see how well it plays with the whole app.