First Class Futures: Specification and implementation of Update Strategies

International audienceA natural way to benefit from distribution is via asynchronous invocations to methods or services. Upon invocation, a request is enqueued at the destination side and the caller can continue its execution. But a question remains: “what if one wants to manipulate the result of an asynchronous invocation?” First-class futures provide a transparent and easy-to-program answer: a future acts as the placeholder for the result of an asynchronous invocation and can be safely transmitted between processes while its result is not needed. Synchronization occurs automatically upon an access to the result. As references to futures disseminate, a strategy is necessary to propagate the result of each request to the processes that need it. This paper studies the efficient transmission of results: it presents three strategies in a semi-formal manner, providing experimental results highlighting their benefits and drawbacks