Experimental Validation and Exploration of A New Kind of Synchronization in Linux

PWCS (Probabilistic Write / Copy-Select) is a new kind of lock-free synchronization mechanism with wait-free characteristics proposed by Nicholas Mc Guire at the 13th real-time Linux workshop, which utilizes the inherent randomness of the modern computer systems. It aims at addressing the multi-reader - single-writer problem in Linux. Based on the original label-based PWCS, we propose a hash-based prototype including two type instances as checksum and CRC (Cyclic Redundancy Check). The key difference between the two prototypes is how to determine the consistency of the data objects. We also implement seqlock (sequential lock) in user space to compare PWCS with RCU (Read-Copy-Update), rwlock (readers-writer lock) and seqlock. The method we used to analyze and validate the high performance of PWCS is also new.