#lock-free

liburcu is a library that implements RCU synchronization in user space. RCU is a synchronization technique very popular by being used at many places in the Linux kernel, where it provides a very simple API.

Keir Fraser

University of Cambridge Technical Report 579

Mutual-exclusion locks are currently the most popular mechanism for interprocess synchronisation, largely due to their apparent simplicity and ease of implementation. In the parallel-computing environments that are increasingly commonplace in high-performance applications, this simplicity is deceptive: mutual exclusion does not scale well with large numbers of locks and many concurrent threads of execution. Highly-concurrent access to shared data demands a sophisticated ‘fine-grained’ locking strategy to avoid serialising non-conflicting operations. Such strategies are hard to design correctly and with good performance because they can harbour problems such as deadlock, priority inversion and convoying. Lock manipulations may also degrade the performance of cache-coherent multiprocessor systems by causing coherency conflicts and increased interconnect traffic, even when the lock protects read-only data.