here - Stefan-Marr.de

9.4. Overall Conclusions
The limitations of the performance evaluation, as discussed in Sec. 8.1.4,
are:
Performance results are not generalizable to applications. The use of microbenchmarks
and kernel benchmarks precludes a generalization of
the performance results to applications. Thus, for fully generalizable
results, a performance evaluation with application benchmarks would
be required.
Performance results provide indications for interpreter-based VMs only. The
low performance of the RoarVM precludes generalization beyond similar
bytecode interpreters. Thus, the obtained results cannot be used to
predict the performance for highly optimized VMs.
9.4. Overall Conclusions
This dissertation is the first to explore how a wide range of concurrent and
parallel programming concepts can be supported by a multi-language VM.
Until now, the research focus was often limited to one specific language or
concept without considering the need for a unifying substrate. However, with
the JVM and CLI being used as multi-language VMs, this is no longer sufficient.
Consequently, it surveys the field of VMs as well as the field of concurrent
and parallel programming and concludes with a set of five general requirements
for VM support. In order to host a wide range of different concepts
efficiently and with correct semantics, a VM needs to provide a flexible optimization
infrastructure, flexible runtime monitoring facilities, a powerful VM interface,
customizable semantics for execution and state access, as well as semantic
enforcement against reflection.
This dissertation focuses on concurrent programming concepts. They benefit
foremost from guaranteeing their semantics in the presence of reflection,
mutable state, and interaction with other languages and libraries. The main
problem with today’s VMs is that contemporary implementation approaches
for concurrent programming concepts have to balance implementation simplicity,
correctly implemented language semantics, and performance. The conclusion
based on these observations is that VMs have to support the notions of
managed state, managed execution, ownership, and controlled
enforcement in order to facilitate the implementation of concurrent programming
concepts.
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