Safe and Familiar Multi-core Programming by Means of a Hybrid Functional and Imperative Language

Abstract

Current (heterogeneous) multi-core environments such as gpGPU architectures are hard to program with normal imperative and object-oriented (OO) languages. There are two basic problems to tackle: (1) it is too easy to program race conditions and dead-locks with the available synchronization primitives, and (2) these environments do not support (or support inefficiently) the instructions required for efficient execution of OO programs, e.g., because function pointers and pointer arithmetic are lacking. We address both problems with a new language that comprises both Functional Programming (FP) and OO programming. We solve problem (1) by auto-parallelization in the functional core where all loops and non-dependent calls can be executed in parallel. FP is to be used to write computational intensive code with safe concurrent memory access. An alternative object model that does neither use pointer arithmetic nor function pointers but smart pointers/proxies (to implement polymorphism) as well as mixins and templates (to implement OO like code reuse) solves problem (2). To cleanly integrate the two language cores, we propose a new integration model that even grants some restricted ways to access state from within FP mode. With the new language and prototype compiler we can transparently parallelize code to target both Cuda and multi-core machines (without annotations from the programmer) and obtain good speedups.