Stefan-Marr.de

Welcome to Academia. That is how I take this one…

Publishing can really be an odyssey, and it all started with my Master thesis. Today, we have the 28th of December 2011. And I think I handed my thesis in somewhere around the 23rd of September 2008. I agree that there have been issues with the original version of the paper, but nothing was so fundamental that it would explain the more than three years it took to get it finally out. Thanks for the warm welcome anyway.

Abstract

CSOM/PL is a software product line SPL derived from applying multi-dimensional separation of concerns MDSOC techniques to the domain of high-level language virtual machine VM implementations. For CSOM/PL, we modularised CSOM, a Smalltalk VM implemented in C, using VMADL virtual machine architecture description language. Several features of the original CSOM were encapsulated in VMADL modules and composed in various combinations. In an evaluation of our approach, we show that applying MDSOC and SPL principles to a domain as complex as that of VMs is not only feasible but beneficial, as it improves understandability, maintainability, and configurability of VM implementations without harming performance.

• CSOM/PL: A Virtual Machine Product Line, Michael Haupt, Stefan Marr, Robert Hirschfeld, Journal of Object Technology, Volume 10, (2011), pp. 12:1-30.
• Paper: PDF.
• BibTex: BibSonomy
• DOI: doi:10.5381/jot.2011.10.1.a12

With Joeri we have been working already for a while on a paper to extend the standard actor model with more parallelism. This work is not completed yet, and there are still some theoretical issues with the approach he designed. But we are working on it!

For the moment, you can have a sneak-peak at the poster abstract for PPoPP’12.

Abstract

The actor model has already proven itself as an interesting concurrency model that avoids issues such as deadlocks and race conditions by construction, and thus facilitates concurrent programming. The tradeoff is that it sacrifices expressiveness and efficiency especially with respect to data parallelism. However, many standard solutions to computationally expensive problems employ data parallel algorithms for better performance on parallel systems.

We identified three problems that inhibit the use of data-parallel algorithms within the actor model. Firstly, one of the main properties of the actor model, the fact that no data is shared, is one of the most severe performance bottlenecks. Especially the fact that shared state can not be read truly in parallel. Secondly, the actor model on its own does not provide a mechanism to specify extra synchronization conditions on batches of messages which leads to event-level data-races. And lastly, programmers are forced to write code in a continuation-passing style (CPS) to handle typical request-response situations. However, CPS breaks the sequential flow of the code and is often hard to understand, which increases complexity and lowers maintainability.

We proposes synchronization views to solve these three issues without compromising the semantic properties of the actor model. Thus, the resulting concurrency model maintains deadlock-freedom, avoids low-level race conditions, and keeps the semantics of macro-step execution.

• Synchronization Views for Event-loop Actors, Joeri De Koster, Stefan Marr, Theo D’Hondt, Proceedings of PPoPP’12, USA, to appear (2012).
• Paper: PDF
  ©ACM, 2012. This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. To appear.
• BibTex: BibSonomy