[kibwen]

Rust's big binaries (these days, about 500kb for hello world) are due to the combination of two factors: 1) it statically-links by default (if you opt for dynamic linking, you get the typical C-esque 10kb binaries) and 2) it ships jemalloc as a custom allocator rather than relying on the system allocator. Considering that jemalloc would be unnecessary for any program targeting a web-based platform, you'd be able to strip down the compiled size considerably.

[mrec]

Is jemalloc's footprint really in the hundreds of kilobytes?

[kibwen]

As source I cite this PR that just landed today:

https://github.com/rust-lang/rust/pull/20218

"It's quite possible that small programs don't use all of jemalloc, and building with -ffunction-sections and -fdata-sections allows the linker (via --gc-sections) to strip out all unused code at link time. This decreases the size of a "hello world" executable for me from 716K to 482K with no measurable impact on link time. After this patch jemalloc is still the largest portion of our hello world executables, but this helps cut down on the size at least somewhat!"