Ruby 3 brings novel improvements such as YJIT and Ractor, but the extent to which these techniques can speed up real applications is unknown. Performance claims should not be accepted solely based on abstract theories or micro benchmarks, but by the supporting evidence from actual applications.

We recently ported a large-scale, open-source Ruby application (Fluentd) to Ruby 3, and conducted a survey to obtain an estimate of the speed improvements over Ruby 2.x. This talk will explain and discuss the results.