Language support for synchronous parallel critical sections

We introduce a new parallel programming paradigm, namely synchronous parallel critical sections. Such parallel critical sections must be seen in the context of switching between synchronous and asynchronous modes of computation. Thread farming allows to generate bunches of threads to solve independent subproblems asynchronously and in parallel. Opposed to that, synchronous parallel critical sections allow to organize bunches of asynchronous parallel threads to execute certain task jointly and synchronously. We show how the PRAM language Fork95 can be extended by a construct join supporting parallel critical sections. We explain its semantics and implementation, and discuss possible applications.