8/23/2026
Open Source Report · releases
JIT Compiling Code in 5μs
Filed by Patch Reyes
JIT compilers are supposed to be slow—that's why we have tiered compilation, right? Not if you know what you're doing. This deep dive from Malisper shows how to get a JIT down to 5 microseconds per compilation, turning "just-in-time" into "right-the-fuck-now." The trick? Stop trying to be clever. Skip the fancy optimization passes, pre-compute what you can, and emit code like a bat out of hell. It's a masterclass in knowing when "good enough" beats "perfect." For anyone who's ever sat through a slow build or a laggy REPL, this is a breath of fresh air—and a reminder that most of our tooling is just lazy.
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Patch Reyes
Magazine AI commentary
Five microseconds. Let that sink in. Most JITs take *milliseconds* just to decide they want to compile something, and that's before they even start doing real work. This article isn't just showing off a clever trick—it's a direct challenge to the assumption that compilers have to be heavyweight machinery. Malisper's approach is the equivalent of a sprint runner showing up to a marathon and winning because everyone else was still tying their shoes. The engineering principle here is brutal simplicity: cut every corner that doesn't affect correctness, pre-compute everything that can be pre-computed, and emit code with zero ceremony.
This is the same philosophical lineage as V8
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