YJIT can make Ruby code run faster, but this is a balancing act, because the JIT compiler itself must consume both memory and CPU cycles to compile and optimize your code while it is running. Furthermore, in large-scale production environments such as those of GitHub, Shopify and Stripe, we end up in a situation where YJIT is compiling the same code over and over again on a very large number of servers, which seems very inefficient. In this presentation, we will go over the design of ZJIT, a nex...