Musl's default allocator causes up to 7x slowdown in Rust applications; developers urged to switch

Summary

The article warns that the default musl allocator causes severe performance degradation (up to 7x slowdown in real-world benchmarks) due to thread contention during memory allocation. The author strongly recommends that all Rust projects immediately switch to an alternative allocator (like mimalloc) in musl environments, even for single-threaded programs or if musl isn't currently a compilation target. The post provides code snippets for implementing the swap in main.rs and Cargo.toml, and explains the root cause as contention between multiple threads when allocating memory.