A highly-efficient wait-free universal construction

We present a new simple wait-free universal construction, called Sim, that uses just a Fetch&Add and an LL/SC object and performs a constant number of shared memory accesses. We have implemented SIM in a real shared-memory machine. In theory terms, our practical version of SIM, called P-SIM, has worse complexity than its theoretical analog; in practice though, we experimentally show that P-SIM outperforms several state-of-the-art lock-based and lock-free techniques, and this given that it is wait-free, i.e., that it satisfies a stronger progress condition than all the algorithms it outperforms. We have used P-SIM to get highly-efficient wait-free implementations of stacks and queues. Our experiments show that our implementations outperform the currently state-of-the-art shared stack and queue implementations which ensure only weaker progress properties than wait-freedom.