Transactional Memory for Unstructured Mesh Simulations

In this paper we study transactional memory (TM) as a new tool for threading codes in this new era of multi- and many-core computers. In particular, we investigate the features and study the applicability of transactional memory as an efficient and easy-to-use alternative for handling memory conflicts in unstructured mesh simulations that use shared memory. The software tool used for our preliminary analysis of this novel construct is IBM's freely available Software Transactional Memory (STM) system. For our studies, we developed the BUSTM benchmark which is a test code with state-of-the-art unstructured-mesh bookkeeping. The numerical algorithms are simplified yet still exhibit most of the salient features of modern unstructured mesh methods. We apply STM to two frequently used algorithm types used in multi-physics codes with realistic 3-D meshes. Our computational experiments indicate a good fit between these application scenarios and the TM features.