[ANN] Supporting Concurrency Abstractions in High-level Language Virtual Machines
Following up on a previous post on this list, I would like to announce the availability of a new version of the ownership-based metaobject protocol (OMOP), and the case studies used for its evaluation.
The case studies include implementations of Clojure agents, event-loop actors in the style of AmbientTalk, an STM system, active objects, and communicating sequential processes.
I put them online as part of my PhD dissertation. The dissertation documents the main ideas in more detail than the previously published paper.
The first implementation was based on AST-transformation to avoid the need for VM support.
While this implementation is still maintained, it is now complemented with a VM-based implementation that shows the performance potential of direct VM support.
The VM with support for the OMOP is based on the RoarVM.
Please see the project web page for additional details, links to the implementation, as well as Smalltalk images for experimenting with the idea.
Below, you'll find the abstract of my dissertation, which you can download here.
Comments or questions are welcome.
Supporting Concurrency Abstractions in High-level Language Virtual Machines
During the past decade, software developers widely adopted JVM and CLI as multi-language virtual machines (VMs). At the same time, the multicore revolution burdened developers with increasing complexity. Language implementers devised a wide range of concurrent and parallel programming concepts to address this complexity but struggle to build these concepts on top of common multi-language VMs. Missing support in these VMs leads to tradeoffs between implementation simplicity, correctly implemented language semantics, and performance guarantees.
Departing from the traditional distinction between concurrency and parallelism, this dissertation finds that parallel programming concepts benefit from performance-related VM support, while concurrent programming concepts benefit from VM support that guarantees correct semantics in the presence of reflection, mutable state, and interaction with other languages and libraries.
Focusing on these concurrent programming concepts, this dissertation finds that a VM needs to provide mechanisms for managed state, managed execution, ownership, and controlled enforcement. Based on these requirements, this dissertation proposes an ownership-based metaobject protocol (OMOP) to build novel multi-language VMs with proper concurrent programming support.
This dissertation demonstrates the OMOP’s benefits by building concurrent programming concepts such as agents, software transactional memory, actors, active objects, and communicating sequential processes on top of the OMOP. The performance evaluation shows that OMOP-based implementations of concurrent programming concepts can reach performance on par with that of their conventionally implemented counterparts if the OMOP is supported by the VM.
To conclude, the OMOP proposed in this dissertation provides a unifying and minimal substrate to support concurrent programming on top of multi-language VMs. The OMOP enables language implementers to correctly implement language semantics, while simultaneously enabling VMs to provide efficient implementations.