Chain: Tasks and Channels for Reliable Intermittent Programs

Tuesday October 18th, 2016
Location: Panther Hollow Conference Room, CIC - 4th Floor
Time: 4:30PM

Alexei Colin (CMU)


Energy harvesting computers enable general-purpose computing using energy collected from their environment. Energy-autonomy of such devices has great potential, but their intermittent power supply poses a challenge. Intermittent program execution compromises progress and leaves state inconsistent. This work describes Chain: a new model for programming intermittent devices.

A Chain program is a set of programmer-defined tasks that compute and exchange data through channels. Chain guarantees forward progress at task granularity. A task is restartable and never sees inconsistent state, because its input and output channels are separated. Our system supports language features for expressing advanced data exchange patterns and for encapsulating reusable functionality.

Chain fundamentally differs from state-of-the-art checkpointing approaches and does not incur the associated overhead. We implement Chain as C language extensions and a runtime library. We used Chain to implement four applications: machine learning, encryption, compression, and sens- ing. In experiments, Chain ensured consistency where prior approaches failed and improved throughput by 2-7x over the leading state-of-the-art system.


Alexei Colin is a fifth year Ph.D. student in the Department of Electrical and Computer Engineering at CMU advised by Prof. Brandon Lucia. He researches compilers, systems and tools for programming intermittently-powered energy-harvesting devices.

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