mimalloc is a compact general purpose allocator from Microsoft. It
consistently outperforms glibc's `malloc()` in allocation-heavy
workloads, such as Lix's evaluator
It's currently only linked in the main `nix` executable, as Boehm's GC
uses its own allocator. Other allocations that *do* go through glibc's
`malloc()` are still much faster, though
Benchmarked on x86_64-linux against Nixpkgs `bd07873`:
| attribute | thunks | lix@`1396012` | mimalloc | uplift |
|-------------------|---------|---------------|----------|--------|
| hello | 206444 | 0.726s | 0.620s | 1.17x |
| chromium | 1177382 | 2.273s | 2.136s | 1.06x |
| firefox-unwrapped | 1394797 | 2.521s | 2.378s | 1.06x |
| texliveFull | 3186440 | 4.992s | 4.672s | 1.07x |
| nixosTests.gnome | 7905808 | 6.115s | 5.723s | 1.07x |
Based-on: https://github.com/NixOS/nix/pull/15596
Co-authored-by: Bernardo Meurer Costa <beme@anthropic.com>
Change-Id: I3ad92eacc075efeaf3d9f7730ada7b29835536a4
