@JIT vs. AOT: i used to think that, too. but graal came out and got 90% of the JIT speed right from the start with a fraction of the time hotspot had for optimization (and of course, with better startup times).
Yes, it seems Graal might finally deliver on the "JIT is better because it is better informed" promise after 20 years. I'm holding my fingers crossed, but I think we need a little more experience with it before victory can be declared.
uh, a misunderstanding, my mistake. what i meant was that graals native-image AOT compiler with the substrate VM achieves 90% of hotspot JIT execution speed pretty much since the project was launched. you may be right that graals JIT is still faster, i don't know about that.
luajit is a great triumph for dynamic compilations and jits; and the fact that it compares favorably to C code (about 70-85% in some of my experiments) is utterly amazing. Especially given that it's essentially the work of one person.
And yet, regardless of how much typing info you give it, it loses out to good AOT compilers, for a similarly implemented algorithm.
GraalVM is unique in that it seems to do better than AOT in some cases. I'd wait a couple more years before declaring JIT victory, though.
The belief is that JITs have information, such as variable values and memory access patterns, that an AOT does not. Well, so far hardly any JIT uses that info, and AOTs do have them from through profile feedback; And also, JITs have to amortize compilation effort and runtime saving, whereas AOT doesn't. So the "JIT is obviously >= AOT" is not foregone conclusion.
