Concurrent programming with revisions and isolation types

Abstract

Building applications that are responsive and can exploit parallel hardware while remaining simple to write, understand, test, and maintain, poses an important challenge for developers. In particular, it is often desirable to enable various tasks to read or modify shared data concurrently without requiring complicated locking schemes that may throttle concurrency and introduce bugs.We introduce a mechanism that simplifies the parallel execution of different application tasks. Programmers declare what data they wish to share between tasks by using isolation types, and execute tasks concurrently by forking and joining revisions. These revisions are isolated: they read and modify their own private copy of the shared data only. A runtime creates and merges copies automatically, and resolves conflicts deterministically, in a manner declared by the chosen isolation type.To demonstrate the practical viability of our approach, we developed an efficient algorithm and an implementation in the form of a C# library, and used it to parallelize an interactive game application. Our results show that the parallelized game, while simple and very similar to the original sequential game, achieves satisfactory speedups on a multicore processor.

A large-scale study on the usage of Java’s concurrent programming constructs

“…First, to the best of our knowledge, this is the first report on the current state of the practice of the usage of concurrent programming constructs in Java. Second, because it hints (RQ1-6) that general purpose solutions being devised by researchers (Burckhardt et al, 2010;Yi et al, 2011) help developers to build parallel applications have some potential for adoption. Third, it suggests there is much room for improving the ways in which exceptions in threads are addressed (RQ7), and that existing proposals (Li et al, 2006) are not mere academic exercises, as it indicates that guidance on how to deal with exceptions is necessary.…”

“…Concurrent programming has been an exciting area of research in the last decade. Although no consensus has emerged on a single model of concurrency, many advances have been made with the development of various contending models (Burckhardt et al, 2010;Yi et al, 2011). Besides that, regardless of the model of concurrency, many researchers (Dig et al, 2009;Goetz et al, 2006;Ishizaki et al, 2011;Okur and Dig, 2012) argue that high level concurrency libraries can improve software quality.…”

Practical parallel and concurrent programming

“…be focused on in more depth for a graduate special topics course. Advanced topics currently include a section on memory models, a section that has a detailed focus on caching behaviours, a section on safe strategies for lock-free data structure creation, plus a section on alternative programming models to synchronization such as transactions or revisions [5]. We may add additional topics to this unit, based on feedback from the initial iterations of the course.…”

Workshop on transitioning to multicore (TMC 2011)

“…To address that difficulty, numerous programming models and systems have been proposed, including transactional memory [7,11], revisions [3], and type systems [2]. However, industry programmers face large amounts of legacy code, and so it may not always be feasible to change the programming model.…”