Ruby performance profiling: an unorthodox approach

We have built an app for one of our clients that allows you to search companies from all over the world, based on key properties like name, country etc and supports even more advanced search queries like CEO last name, sales margin etc. In our implementation we have a Rails app that is sitting as a middleman between an old, inflexible API and our shiny new front-end using EmberJS. Basically it acts as an API Gateway and we have employed various performance tricks like memoization on static or rarely changing data as well as caching to the origin data using Redis.