Virtual Machine Support for Many-Core Architectures: Decoupling Abstract from Concrete Concurrency Models

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

Actor Frameworks for the JVM Platform: . . .

The problem of programming scalable multicore processors has renewed interest in message-passing languages and frameworks. Such languages and frameworks are typically actororiented, implementing some variant of the standard Actor semantics. This paper analyzes some of the more significant efforts to build actor-oriented frameworks for the JVM platform. It compares the frameworks in terms of their execution semantics, the communication and synchronization abstractions provided, and the representations used in the implementations. It analyzes the performance of actor-oriented frameworks to determine the costs of supporting different actor properties on JVM. The analysis suggests that with suitable optimizations, standard Actor semantics and some useful communication and synchronization abstractions may be supported with reasonable efficiency on the JVM platform