Transactifying Apache

Apache is a large-scale industrial multi-process and multi-threaded application, which uses lock-based synchronization. The authors report on their experience in modifying Apache to employ transactional memory instead of locks, a process they refer to as transactification; they are not aware of any previous efforts to transactify legacy software of such a large scale. Along the way, they learned some valuable lessons about which tools one should use, which parts of the code one should transactify and which are better left untouched, as well as on the intricacy of commit handlers.