here - Stefan-Marr.de

8.1. Evaluation Strategy
The RoarVM was chosen over the CogVM for its significantly lower implementation
complexity, 1 enabling the evaluation of the benefits of VM support
with a significantly lower implementation effort.
Motivation for using LRSTM and AmbientTalkST The performance evaluation
relies on the AmbientTalkST and LRSTM case studies to compare the
performance of ad hoc implementations with OMOP-based implementations.
The evaluation restricts itself to these two case studies, because the semantic
differences between the ad hoc implementation of Clojure agents and the
OMOP-based implementation are significant (cf. Sec. 6.2.1) rendering any performance
result incomparable.
However, AmbientTalkST and LRSTM yield two relevant data points that
represent two major concurrent programming concepts. As argued in Sec. 2.5,
event-loop actors are a natural fit for the implementation of event-driven userinterfaces.
JCoBox [Schäfer and Poetzsch-Heffter, 2010] and AmbientTalk [Van
Cutsem et al., 2007] show that these ideas are explored in research. Furthermore,
WebWorker 5 and Dart 6 demonstrate the adoption in industry. Software
transactional memory found adoption in languages such as Clojure 7
or Haskell 8 and as a compiler extension for GNU GCC 4.7. 9
Furthermore, these two case studies customize distinct intercession handlers
of the OMOP, and thus are subject to different performance effects.
AmbientTalkST primarily customizes method execution (cf. Sec. 6.2.3), while
LRSTM customizes state access and primitives execution (cf. Sec. 6.2.2).
In order to have comparable results, both AmbientTalkST implementations
observe the same semantics, i. e., neither implementation enforces state encapsulation
for global state. While Sec. 6.2.3 discussed a solution for state
encapsulation based on the OMOP, providing the same degree of encapsulation
for the ad hoc implementation would have required significant addi-
1 Our discussions with Eliot Miranda, author of the CogVM, at the Deep into Smalltalk school, 2
the VMIL’11 workshop, 3 and as a co-mentor for the 2012 Google Summer of Code project to
port the CogVM to ARM, 4 made it clear that the CogVM would requires engineering and
research effort that goes beyond the scope of this dissertation (cf. Sec. 9.5.2).
2 http://www.inria.fr/en/centre/lille/calendar/smalltalk
3 http://www.cs.iastate.edu/~design/vmil/2011/program.shtml
4 http://gsoc2012.esug.org/projects/arm-jitter
5 http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html
6 http://api.dartlang.org/docs/continuous/dart_isolate.html
7 http://clojure.org
8 http://www.haskell.org
9 http://gcc.gnu.org/wiki/TransactionalMemory
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