JVM Bytecodes arranged according to the Function

256 Pages·2013·3.87 MB·English

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Towards Efficient Execution of a GALS MoC Based
System Level Language
Muhammad Nadeem
Supervisors: Dr. Morteza Biglari-Abhari
Prof. Zoran Salcic
A thesis submitted in partial fulfilment of the requirements for the degree of
Doctor of Philosophy in Electrical and Electronic Engineering,
The University of Auckland

Abstract
Embedded systems include a broad range of electronic systems, from household appliances to
safety critical systems such as medical systems, automotive electronics and avionics. Due to
growing complexity of the applications, these systems consist of a number of computational
intensive units running concurrently. They also interact with each other and with environment,
repeatedly reading inputs, doing computations and responding appropriately. These computa-
tional units may have different response times; hence, they may need to run concurrently at
different speeds. These systems may be considered as GALS (Globally Asynchronous Locally
Synchronous), which typically consist of a collection of components that execute concurrently
and communicate using possibly slow or unreliable channels. SystemJ is a system level pro-
gramminglanguagebasedonGALSmodelofcomputationallowingtheasynchronouscoupling
of synchronous reactive modules at the top level, which execute at different speeds. It extends
Java with Esterel-like constructs for the synchronous concurrency and reactivity, and CSP-like
constructs for the asynchronous concurrency. SystemJ targets a large range of heterogeneous
embeddedsystemsthatcombinedata-intensiveandcontrol-dominatedcomputations(heteroge-
neous)inadditiontosynchronousandasynchronousconcurrency.
Although, the problem of modeling complex systems has largely been solved by raising level
of abstraction, there is still need for efficient execution platforms to realize such applications.
While, there have been efforts towards supporting heterogeneous applications, they primarily
focused on the reactive part of applications. In summary, developing architectural support for
heterogeneousembeddedapplicationshasbeenthemainfocusofthisresearch.
This thesis proposes improvements to some existing architectures as well as developing new
architecturesthatmakeuseoftheformalunderlyingstructureofthelanguagetoachievehigher
executionefficiencyintheGALSparadigm. Thesearchitecturesexecutecontrolanddata-driven
operations along with asynchronous and synchronous concurrent processes in an efficient way.
Our novel solutions range from extensions to a single CPU architecture to multiprocessor ar-
chitectures, all while considering computational demands and resource constraints. We started
with the deployment of Java Optimized Processor (JOP) to execute SystemJ programs com-
piled to Java and improved it by extending its architecture to include the reactive features. We
suggestednovelarchitectureswhichefficientlyexecutetheSystemJprogramscompiledbysep-
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aratingcontrolanddata-operationsonasinglecorebyembeddingcontroloperationsinsidethe
data-operationrepresentedinJavabytranslatingthemtocustombytecodes. Werefinedthisap-
proach by providing two separate modes of execution for control and data-oriented operations.
This approach is further extended to multiprocessor architecture to speed up the execution and
meet the computational demands required by high-end embedded systems. We experimentally
evaluated all proposed architectures to validate their effectiveness. Better performance, lower
code density and resources usage have been achieved compared to previous approaches for
SystemJexecution,thusprovingitssuitabilityforheterogeneousembeddedapplications.
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Tomyparentsandfamily
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Acknowledgements
FirstandforemostIoffermysincerestgratitudetomysupervisors,Dr. MortezaBiglari-Abhari
and Prof. Zoran Salcic, who have supported me thoughout my thesis. Their time, expertise,
support and guidance have been invaluable and appreciated. I attribute the level of my Doctor
of Philosphy degree to their encouragement and effort and without them this thesis, too, would
not have been completed or written. The joy and enthusiasm they had for the research was
contagiousandmotivationalforme,evenduringtoughtimes.
My time at University of Auckland was made enjoyable in large part due to the many friends
andgroupsthatbecameapartofmylife. Iamgratefulfortimespentwithroommates,friends,
andmanyotherpeople.
Last but not least, my deepest thanks to my parents and family for their continuous support
throughout these years. Their understanding and support ecouraged me to do my best in Ph.D
research.
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