# 04.04. rustc parallel compiler support

## Topic

[compiler-team#492](https://github.com/rust-lang/compiler-team/issues/492)

People involved: [Sparrow Li](https://rust-lang.zulipchat.com/#user/353056), [lqd](https://rust-lang.zulipchat.com/#user/116113), @**Zoxc**

## Current situation

From ([comment](https://rust-lang.zulipchat.com/#narrow/channel/187679-t-compiler.2Fparallel-rustc/topic/Parallel.20compilation.20strategy/near/509080577)):
> The biggest (probably only) obstacle at the moment is how to avoid deadlocks fundamentally. In fact, after #137731 was merged, all current deadlock issues can no longer be reproduced in CI, but we still hope to avoid deadlocks fundamentally to ensure that future code changes will not cause new deadlocks.

- Pull request [rustc-rayon#12](https://github.com/rust-lang/rustc-rayon/pull/12) needs a reviewer with proper context ([comment](https://rust-lang.zulipchat.com/#narrow/channel/187679-t-compiler.2Fparallel-rustc/topic/Path.20to.20stabilization/near/508891802)).
- This is blocking [rustc#132051](https://github.com/rust-lang/rust/pull/132051).
- @**oli** added to their TODO list recently ([comment](https://rust-lang.zulipchat.com/#narrow/channel/187679-t-compiler.2Fparallel-rustc/topic/Disable.20parallelism.20expect.20for.20main.20loops/near/509125836))
- The other topic is if we want to pull rayon in-tree ([Zulip discussion](https://rust-lang.zulipchat.com/#narrow/channel/187679-t-compiler.2Fparallel-rustc/topic/Disable.20parallelism.20expect.20for.20main.20loops/near/509081694)). The fork of rayon seems to be basically maintained by @**Josh Stone (cuviper)** ([contrib graph](https://github.com/rayon-rs/rayon/graphs/contributors?from=15.12.2023&to=30.3.2025))