STMX
High-performance transactional memory for Common Lisp
STMX is a high-performance Common Lisp library for composable Transactional Memory (TM), a concurrency control mechanism aimed at making concurrent programming easier to write and understand.
Instead of traditional lock-based programming, one programs with atomic memory transactions: if a memory transaction returns normally it gets committed, if instead it signals an error (Lisp slang for throwing an exception) it is rolled back.