seqloq

Seqlocks for Rust, inspired by the Linux kernel's implementation.

Check out the API documentation.

seqloq supports optimistic, lock-free reads of thread-shared data. The reader checks a sequence number before and after reading, and retries if the data structure changed during the read. When the workload consists mainly of reads, this can improve performance vs. a traditional mutex.

Here's a histogram for read latency on a 32-byte data structure, with a few infrequent writes and 200 concurrent readers:

The write performance is also competitive:

seqloq can also prevent starvation of writers, because writers have absolute priority.

To render your own histograms:

cargo build --release
./target/release/bench
./plot.py

The hard-coded ranges in plot.py will probably need adjustment for your machine.