Performance Improvements!
emp-wasm-engine is now much faster 🏎️
Results
Note: Versions 0, 1, 2 are running all parties on a single thread, which isn't realistic, but the relative improvements are real. Version 3 fixes this, providing numbers that are relevant to real deployments.
Above: Video of the host when running JumboSwap locally in 5 tabs.
IO Buffering
MPC Framework provides an abstraction for IO so that you can supply any transport for moving bytes between the parties. When I originally created emp-wasm, I did the IO in a pretty naive way - when the C++ code wants to send some bytes, it sends that to JS immediately so that JS can send on the websocket/etc. Now C++ will buffer up to 64KiB before passing it to JS, and this makes a huge difference (see v0->v1 in the sha1 results graph).
Importing Circuits
emp-toolkit provides a bristol circuit parser using C++'s istringstream. When we compile this to WebAssembly using Emscripten, it's very very slow. So slow that it's much faster to use JS to parse and encode the bristol into binary, and send that binary to C++ instead. For the 2.4MiB sha1 circuit, this reduces the circuit loading time from 1500ms to under 100ms.
In future, I think this space will benefit from a much better standard format
for circuits. It's actually a bit silly that we have Summon going to the trouble
to serialize the circuit into this verbose format and then emp-wasm has to spend
time parsing it. Bristol format also lacks real descriptions for its input and
output bits, which is why we currently provide metadata separately -
circuit_info.json.
I hope that in the not-too-distant future we can unify these into a single compact circuit format. This will improve speed and reduce complexity. Even if you want a readable format for debug purposes, we could provide something much better than Bristol. We should treat Bristol as a legacy format and provide backwards compatibility by providing a Bristol serializer that is only used when necessary.
Join Us!
- Telegram group
- Discord (Channel name: 🔮-mpc-framework)
- Github Repo ⭐️
- Website
Thanks for building privacy‑preserving magic with us! 🪄
