“…Instead, we are interested in developing asynchronous techniques that avoid this blocking behaviour by permitting processors to operate on whatever data they have, even if new data has not yet arrived from other processors. To date, there has been work on both the theoretical (Chazan and Miranker, 1960;Baudet, 1978;Bertsekas and Tsitsiklis, 1989) and the practical (Bull and Freeman, 1992;Bahi et al, 2006; de Jager and Bradley, 2010) aspects of such algorithms. To reason about these algorithms we need to understand what drives the speed of their convergence, but existing results merely provide sufficient conditions for the algorithms to converge, and do not help us to answer some of questions arising in the use of asynchronous techniques in large, tightly coupled parallel systems of relevance to Exascale computing.…”