Atomic Dynamic Upgrades Using Software Transactional Memory

In this paper, we propose the use of a Software Transactional Memory to implement a Dynamic Software Upgrade system that combines two desirable properties. First, it provides a simple semantics to the developer, while allowing upgrades to occur atomically, concurrently with the execution of the program. Second, it converts the program's data lazily, as data is progressively accessed by the execution of the upgraded program. We present also experimental results that show that our lazy approach to software upgrades is able to upgrade a system without affecting significantly the maximum response time of the system's operations, whereas an immediate approach shows values of maximum response time up to three orders of magnitude higher.