Atomic Boxes: Coordinated Exception Handling with Transactional Memory

摘要

In concurrent programs raising an exception in one thread does not prevent others from operating on an inconsistent shared state. Instead, exceptions should ideally be handled in coordination by all the threads that are affected by their cause. In this paper, we propose a Java language extension for coordinated exception handling where a named abox (atomic box) is used to demarcate a region of code that must execute atomically and in isolation. Upon an exception raised inside an abox, threads executing in dependent aboxes, roll back their changes, and execute their recovery handler in coordination. We provide a dedicated compiler framework, CXH, to evaluate experimentally our atomic box construct. Our evaluation indicates that, in addition to enabling recovery, an atomic box executes a reasonably small region of code twice as fast as when using a failbox, the existing coordination alternative that has no recovery support.