Questions And Answers About BSP

Bulk Synchronous Parallelism (BSP) is a parallel programming model that abstracts from low-level program structures in favour of supersteps. A superstep consists of a set of independent local computations, followed by a global communication phase and a barrier synchronisation. Structuring programs in this way enables their costs to be accurately determined from a few simple architectural parameters, namely the permeability of the communication network to uniformly-random traffic and the time to synchronise. Although permutation routing and barrier synchronisations are widely regarded as inherently expensive, this is not the case. As a result, the structure imposed by BSP comes for free in performance terms, while bringing considerable benefits from an application-building perspective. This paper answers the most common questions we are asked about BSP and justifies its claim to be a major step forward in parallel programming. 1 Why is another model needed? In the 1980s a large number ..