Performance

Every figure here was measured on the repository’s own fixtures, on an Apple M series machine. They are recorded because each one changed a decision.

Compilation

For hosted.elf — 99 KiB, 55 functions, built with alloc:

Code generation is ~99% of compile time. That is why caching targets codegen and nothing else, and why the ELF front end has never needed optimising.

Compilation is eager and whole-program: every function in .text is compiled when the module is created, whether or not it is ever called.

Caching

A warm cache is 2.6× faster than none; a cold one is 2× slower. See Caching.

Interruption

0.2% on a 50-million-iteration tight loop — the worst case, since the check is proportionally largest where the loop body is smallest. Straight-line code pays nothing.

A first attempt measured this against a recursive fib and reported −20%, which was noise: fib is call-dominated, so the loop check barely features. Measuring the wrong workload is easier than it looks.

Optimisation level

OptLevel::None compiles faster; OptLevel::Speed generates better code. On these fixtures the difference in compile time is small and in run time not reliably measurable, because the fixtures are too short to say anything useful.

There is no benchmark suite yet, so treat any claim about guest execution speed as unmeasured. The figures above are all about the compiler, not the code it produces.