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Thomas Kunz |
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Systems and Computer Engineering |
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Carleton University |
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http://kunz-pc.sce.carleton.ca/ |
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tkunz@sce.carleton.ca |
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Motivation and Related Work |
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What to Visualize |
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How to Visualize |
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Tracing and Visualization |
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Event Generation |
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Event Collection |
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Event Visualization |
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Conclusions and Future Work |
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Applications involving mobile agents are
complex: |
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All the problems of parallel and distributed
applications (concurrency, scale, non-determinism, etc.) |
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Additional problem: where are agents? |
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Visual tools used widely in parallel and
distributed programming environments for program understanding, fault and
performance debugging, … |
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Some popular visualization tools: |
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Poet |
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XPVM |
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Polka |
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Paragraph |
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All support visualizing execution dynamics, none
explicitly shows mobility of code |
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Visualization based on definition of “events” |
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Events are lowest level of observable behaviour |
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Sample events: send/receive a message, create a
thread/process, complete an encryption task, …. |
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Target environment: Objectspace Voyager |
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No distinction between objects and agents
(agents are objects that move autonomously) |
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Our focus: objects/agents and their mobility |
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Object/agent creation and destruction |
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Events related to mobility: departure and
arrival |
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Events are generated by adding instrumentation |
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Operating system |
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Runtime system, Middleware |
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Application (our approach) |
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To reduce effort, use: |
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class inheritance (inherit from a “Visualizable”
class) |
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adaptor pattern for classes that cannot use
inheritance (in single-inheritance systems) |
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Special features of Java/Voyager: |
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Callbacks for migration-related events provided |
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Due to dynamic garbage collection, we cannot
reliably detect object destruction |
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Identified interesting events to visualize
dynamics of mobile agents |
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Developed runtime system support to generate and
collect these events |
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Provide a visualization toolkit (based on XPVM)
to display agent movements within a process-time diagram |
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Future work: |
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Include other interesting events (method
invocations…) |
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Study probe effect and performance for on-line
visualization |
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Collect user feedback to validate usefulness of
tool |
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Identify and support other interesting views
(network, etc.) |
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Notes