✔ Minimising the size of wasmtime executable? · wasmtime

Stream: wasmtime

Topic: ✔ Minimising the size of wasmtime executable?

Mats Brorsson (Oct 24 2023 at 09:29):

I met a person at Wasm research day in Munich (I never registered the name, sorry) who told me that it should be possible to reduce the size of the CLI executable significantly. When compiling it straight out of the box (repo) with --release the executable is about 50 MB. With the following options in Cargo.toml:

[profile.release]
strip = true  # Automatically strip symbols from the binary.
opt-level = "z"  # Optimize for size.
lto = true

I can get it down to 19 MB.

The question is: is it possible to reduce it further without hurting performance? I'd like to avoid dynamically linked libraries.

Jeff Parsons (Oct 24 2023 at 11:03):

I think this is what you're looking for: https://github.com/bytecodealliance/wasmtime/pull/7282 There have also been some follow-up PRs, but I think everything else should be discoverable from this.

Gate many CLI/Wasmtime features behind Cargo features by alexcrichton · Pull Request #7282 · bytecodealliance/wasmtime

This PR is borne out of discussions from last week's CG meetings about the suitability of Wasmtime in embedded scenarios. One of the primary concerns that arose was the binary size of the Wasmtime ...

Alex Crichton (Oct 24 2023 at 14:15):

Documentation for producing a minimal build is now here and example release artifacts are here as wasmtime-min executables inside of each CLI tarball. Currently this is ~2M, and depending on your use case that can be smaller too even.

If you've got size concerns still please let us know as it's something we'd like to be aware of!

Release dev · bytecodealliance/wasmtime

A fast and secure runtime for WebAssembly. Contribute to bytecodealliance/wasmtime development by creating an account on GitHub.

Ralph (Oct 25 2023 at 12:55):

what is this evil?

Chris Fallin (Oct 25 2023 at 16:20):

@Alex Crichton if you can get it down to 1.44MB, I will celebrate by purchasing some retro floppies and a floppy drive and creating the first ever Wasmtime Installation Disk

Till Schneidereit (Oct 25 2023 at 16:42):

why stop there? I say 720kb or bust!

Ralph (Oct 25 2023 at 17:03):

No one should ever need more than 720kb... wait.

Lann Martin (Oct 25 2023 at 17:10):

This is just a curiosity for me so no pressure to do anything about it but I don't see artifacts at the link; were they replaced by CI?

Ralph (Oct 25 2023 at 17:13):

I found them inside the .xz files -- two different executables

Alex Crichton (Oct 25 2023 at 17:14):

Yeah the new "min" artifacts are in the normal tarballs as the wasmtime-min executable or the libwasmtime-min.so dynamic library (or libwasmtime-min.a)