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> But even then, C wins by a lot.

C links dynamically to its libraries. Rust does not (by default).

This overhead is a constant overhead so it rarely matters. When it does, you can strip it down further and get it to the same level as C.

This is not evidence of a fat runtime, just a different default compilation strategy that prodces larger binary executables. jemalloc is (an optional) part of the runtime, but the rest isn't.

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Sure. It's not a fair comparison. But dynamically linking rust's std isn't an option. If you are optimizing for executable size, c wins because dynamically linking libc is possible. This is even true controlling for glibc, since most rust code also dynamically links glibc too (including hello world). In fact, rust's hello world has quite a few more shared dependencies than the equivalent c anyway: it uses libdl, librt, libpthread, and libgcc_s as well.

Dynamically linking to rust std (with a specially compiled libstd dylib) is an option iirc, just that nobody does it. Lack of stable ABI makes it less useful, but if you really need to do it there's nothing stopping you.

I suspect rust hello world using those libraries is due to a lack of LTO? Hello world doesn't need any of those.

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