Encapsulated open nesting for STM: fine-grained higher-level conflict detection

Abstract

Open nesting allows replacing the automatic detection of conflicting memory accesses used in transactional memory (TM) with programmer-specified higher-level conflict detection. Higher-level conflict detection allows removing conflicts of commuting operations where the automatic conflict detection is too conservative. Different conflict detection schemes are incompatible with each other and thus must operate on separate memory locations to prevent inconsistencies. Using open nesting, a programmer implements this separation manually using source code modifications possibly assisted by static checks.