A model for the design and programming of multi-cores

This paper describes a machine/programming model for the era of multi-core chips. It is derived from the sequential model but replaces sequential composition with concurrent composition at all levels in the program except at the level where the compiler is able to make deterministic decisions on scheduling instructions. These residual sequences of instructions are called microthreads and they are small code fragments that have blocking semantics. Dependencies that would normally be captured by sequential programming are captured in this model using dataflow synchronisation on variables in the contexts of these microthreads. The resulting model provides a foundation for significant advances in computer architecture as well as operating systems and compiler development. The paper takes a high-level perspective on the field of asynchronous distributed systems and comes to the conclusion that dynamic and concurrent models are the only viable solution but that these should not necessarily be visible to the users of the system.