The loom documentation has significantly more documentation on how to use loom. But if you just want a jump-start, first add this to your Cargo.toml
.
[target.'cfg(loom)'.dependencies] loom = "0.7"
Next, create a test file and add a test:
use loom::sync::Arc; use loom::sync::atomic::AtomicUsize; use loom::sync::atomic::Ordering::{Acquire, Release, Relaxed}; use loom::thread; #[test] #[should_panic] fn buggy_concurrent_inc() { loom::model(|| { let num = Arc::new(AtomicUsize::new(0)); let ths: Vec<_> = (0..2) .map(|_| { let num = num.clone(); thread::spawn(move || { let curr = num.load(Acquire); num.store(curr + 1, Release); }) }) .collect(); for th in ths { th.join().unwrap(); } assert_eq!(2, num.load(Relaxed)); }); }
Then, run the test with
RUSTFLAGS="--cfg loom" cargo test --test buggy_concurrent_inc --release
Loom currently does not implement the full C11 memory model. Here is the (incomplete) list of unsupported features.
SeqCst
accesses (e.g. load
, store
, ..): They are are regarded as AcqRel
. That is, they impose weaker synchronization, causing Loom to generate false alarms (not complete). See #180 for example. On the other hand, fence(SeqCst)
is supported.load_buffering
test case in tests/litmus.rs
.This project is licensed under the MIT license.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in loom
by you, shall be licensed as MIT, without any additional terms or conditions.