arXiv subjects

Laurie Hendren

Publications and source records attributed to Laurie Hendren.

4 recordsLinked to original sources

arXiv2019

Pando: Personal Volunteer Computing in Browsers

The large penetration and continued growth in ownership of personal electronic devices represents a freely available and largely untapped source of computing power. To leverage those, we present Pando, a new volunteer computing tool based on a declarative concurrent programming model and implemented using JavaScript, WebRTC, and WebSockets. This tool enables a dynamically varying number of failure-prone personal devices contributed by volunteers to parallelize the application of a function on a stream of values, by using the devices' browsers. We show that Pando can provide throughput improvements compared to a single personal device, on a variety of compute-bound applications including animation rendering and image processing. We also show the flexibility of our approach by deploying Pando on personal devices connected over a local network, on Grid5000, a French-wide computing grid in a virtual private network, and seven PlanetLab nodes distributed in a wide area network over Europe.

cs.DC↗

arXiv2019

Genet: A Quickly Scalable Fat-Tree Overlay for Personal Volunteer Computing using WebRTC

WebRTC enables browsers to exchange data directly but the number of possible concurrent connections to a single source is limited. We overcome the limitation by organizing participants in a fat-tree overlay: when the maximum number of connections of a tree node is reached, the new participants connect to the node's children. Our design quickly scales when a large number of participants join in a short amount of time, by relying on a novel scheme that only requires local information to route connection messages: the destination is derived from the hash value of the combined identifiers of the message's source and of the node that is holding the message. The scheme provides deterministic routing of a sequence of connection messages from a single source and probabilistic balancing of newer connections among the leaves. We show that this design puts at least 83% of nodes at the same depth as a deterministic algorithm, can connect a thousand browser windows in 21-55 seconds in a local network, and can be deployed for volunteer computing to tap into 320 cores in less than 30 seconds on a local network to increase the total throughput on the Collatz application by two orders of magnitude compared to a single core.

cs.DC↗

arXiv2019

Personal Volunteer Computing

We propose personal volunteer computing, a novel paradigm to encourage technical solutions that leverage personal devices, such as smartphones and laptops, for personal applications that require significant computations, such as animation rendering and image processing. The paradigm requires no investment in additional hardware, relying instead on devices that are already owned by users and their community, and favours simple tools that can be implemented part-time by a single developer. We show that samples of personal devices of today are competitive with a top-of-the-line laptop from two years ago. We also propose new directions to extend the paradigm.

cs.DC↗

arXiv2018

A Formalization for Specifying and Implementing Correct Pull-Stream Modules

Pull-stream is a JavaScript demand-driven functional design pattern based on callback functions that enables the creation and easy composition of independent modules that are used to create streaming applications. It is used in popular open source projects and the community around it has created over a hundred compatible modules. While the description of the pull-stream design pattern may seem simple, it does exhibit complicated termination cases. Despite the popularity and large uptake of the pull-stream design pattern, there was no existing formal specification that could help programmers reason about the correctness of their implementations. Thus, the main contribution of this paper is to provide a formalization for specifying and implementing correct pull-stream modules based on the following: (1) we show the pull-stream design pattern is a form of declarative concurrent programming; (2) we present an event-based protocol language that supports our formalization, independently of JavaScript; (3) we provide the first precise and explicit definition of the expected sequences of events that happen at the interface of two modules, which we call the pull-stream protocol; (4) we specify reference modules that exhibit the full range of behaviors of the pull-stream protocol; (5) we validate our definitions against the community expectations by testing the existing core pull-stream modules against them and identify unspecified behaviors in existing modules. Our approach helps to better understand the pull-stream protocol, to ensure interoperability of community modules, and to concisely and precisely specify new pull-stream abstractions in papers and documentation.

cs.PL↗