Hmm. This is one of the unexpected upsides to systems using JIT compilation that I guess we tend to take for granted. The very fact that a JITC runs in parallel

Hmm. This is one of the unexpected upsides to systems using JIT compilation that I guess we tend to take for granted. The very fact that a JITC runs in parallel to the app means the compiler developers care intensely about the performance of the compiler itself - any regression increases warmup time which is a closely tracked metric. As long as you can tolerate the warmup, and at least for Java it's not really a big deal for many apps these days because C1/C2 are just so fast, you get fast iteration speeds with pretty good code generation too. The remaining performance pain points in Java apps are things like the lack of explicit vectorisation, value types etc, which are all being worked on.