Stefan-Marr.de

On the first day here at the summer school, the organizers gave us the opportunity to present our research ideas to the lecturers and other participants.

I presented my idea on extending the virtual machine models with explicit support for concurrency models. My brief presentation focused on using multiple-language virtual machines to provide support for domain-specific concurrent languages. It basically states the question whether it is possible to use the concepts of locality and encapsulation as a common foundation for a wide range of different models. Since I am at the very beginning of working on this specific idea, there aren’t any answers yet.

Already quite a while ago, I was involved in writing a workshop paper about an actor model for virtual machines. Actually, the main idea was to find a concurrency model for a VM which supports multi-dimensional separation of concerns. However, AOP is not that interesting for me at the moment, so I am focussing on the concurrency, especially the actor-based VM model.

After one year, I am back looking at that paper, and it still looks like a great model. Think, I will incorporate it into my manycore VM now

Abstract

In this position paper we propose to extend an existing delegation-based machine model with concurrency primitives. The original machine model which is built on the concepts of objects, messages, and delegation, provides support for languages enabling multi-dimensional separation of concerns (MDSOC). We propose to extend this model with an actor-based concurrency model, allowing for both true parallelism as well as lightweight concurrency primitives such as coroutines. In order to demonstrate its expressiveness, we informally describe how three high-level languages supporting different concurrency models can be mapped onto our extended machine model. We also provide an outlook on the extended model’s potential to support concurrency-related MDSOC features.

• Towards an Actor-based Concurrent Machine Model, Hans Schippers, Tom Van Cutsem, Stefan Marr, Michael Haupt, Robert Hirschfeld, Proceedings of the fourth workshop on the Implementation, Compilation, Optimization of Object-Oriented Languages, Programs and Systems (ICOOOLPS), New York, NY, USA, ACM (2009), p. 4–9.
• Paper: PDF
  ©ACM, 2009. This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ICOOOLPS’09 July 6, 2009, Genova, Italy. http://doi.acm.org/10.1145/1565824.1565825
• BibTex: BibSonomy

My second workshop paper got published at the ACM Digital Library. This is actually only an abstract, but nonetheless, it might be interesting for people looking into the design of virtual machines and especially bytecodes/intermediate languages.

Abstract

Today’s major high-level language virtual machines (VMs) are becoming successful in being multi-language execution platforms, hosting a wide range of languages. With the transition from few-core to many-core processors, we argue that VMs will also have to abstract from concrete concurrency models at the hardware level, to be able to support a wide range of abstract concurrency models on a language level. To overcome the lack of sufficient abstractions for concurrency concepts in VMs, we proposed earlier to extend VM intermediate languages by special concurrency constructs[PLACES09].

As a first step towards this goal, we try to fill a gap in the current literature and survey the intermediate language design of VMs. Our goal is to identify currently used techniques and principles as well as to gain an overview over the available concurrency related features in intermediate languages.

Another aspect of interest is the influence of the particular target language, for which the VM is originally intended, on the intermediate language.

• Paper: PDF
  ©ACM, 2009. This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in VMIL’09, October 25, 2009. http://doi.acm.org/10.1145/1711506.1711509
• BibTex: BibSonomy

Slides of the Talk at VMIL09/OOPSLA

Finally, my first workshop paper got published, which was a little odyssey with some misunderstandings, but anyway, now it is out. It is just a position paper, thus, do not expect to many insights. However, what it describes is my big plan, and hopefully the story of my PhD. Am working on it…

Abstract

The upcoming many-core architectures require software developers to exploit concurrency to utilize available computational power. Today’s high-level language virtual machines (VMs), which are a cornerstone of software development, do not provide sufficient abstraction for concurrency concepts. We analyze concrete and abstract concurrency models and identify the challenges they impose for VMs. To provide sufficient concurrency support in VMs, we propose to integrate concurrency operations into VM instruction sets.

Since there will always be VMs optimized for special purposes, our goal is to develop a methodology to design instruction sets with concurrency support. Therefore, we also propose a list of trade-offs that have to be investigated to advise the design of such instruction sets.

As a first experiment, we implemented one instruction set extension for shared memory and one for non-shared memory concurrency. From our experimental results, we derived a list of requirements for a full-grown experimental environment for further research.

• Paper: PDF
• EPTCS: Proceedings Second International Workshop on Programming Language Approaches to Concurrency and Communication-cEntric Software
• BibTex: BibSonomy

Slides of the Talk at PLACES09