How the Ruby Global VM Lock Impacts App Performance

Have you ever heard of Ruby's Global VM Lock? Maybe you've heard of the GIL instead? Spoiler: It's an implementation detail of Ruby that can have a big impact on latency and performance of applications. At a high-level, it prevents Ruby code across multiple threads from running in parallel, while still safely allowing concurrency. Join me as we explore what the GVL is; what it is not; and how we can use the `gvl-tracing` gem to show it in action. We’ll also look into how Ractors, M:N scheduling and fibers fit into this story. By the end of the talk you’ll have the tools to evaluate if your own applications are being impacted, as well as learn a number of do’s and don’ts of Ruby performance.