Executing zkAsm code from Rust

[aborg-dev]

Context

As a part of ZK WASM compiler (https://github.com/near/wasmtime) written in Rust we are compiling WASM code (tests like this one) to zkAsm and want to execute the resulting zkAsm code.

At the moment, we use a nodejs interpreter to run each zkAsm file using this script. This provides the necessary functionality, but the startup time of npm run is around 700ms which would likely be too slow when we have more than 100 tests. We want to find a way to run these tests faster. We can't easily batch the execution into a single invocation of npm run as zkAsm files are generated on the fly by Rust tests that run in parallel.

One of the ideas was to use https://deno.com/ runtime to run the JS code. This way it could be possible to embed Deno runtime into Rust binary which would remove the overheads of starting a subprocess. I did a quick prototype but it would require some changes to zkAsm codebase.

See https://near.zulipchat.com/#narrow/stream/295306-pagoda.2Fcontract-runtime/topic/Running.20zkAsm.20code.20from.20Rust for full discussion.

Questions

1. Is there a way to run zkAsm code in Rust? Is there one planned in the future?
2. Have you investigated using Deno to run zkAsm tooling and would that be a good direction to research?

[Nikopiter]

Hello and good question!

[krlosMata]

I will explain how we run zkasm test in parallel.
We use the well know framework mocha to run the tests. This framework allows you to run test in parallel by just adding --parallel and you can define --jobs $NUM_CPUS to use.

There must be a startup phase where all *.js mocha files are generated:

• https://github.com/0xPolygonHermez/zkevm-rom/blob/main/package.json#L24
• https://github.com/0xPolygonHermez/zkevm-rom/blob/main/tools/parallel-testing/gen-parallel-tests.js
  Then, we just run all of them in parallel:
• https://github.com/0xPolygonHermez/zkevm-rom/blob/main/package.json#L25

The startup phase should be very fast. The testing phase depend pretty much on the test you are running and the machine CPUs