DIPLOMA: Consistent and coherent shared memory over mobile phones

Jason Gao, Anirudh Sivaraman, Niket Agarwal, Hao Qi Li, Li Shiuan Peh

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Location-based services for mobile devices are pervasive, and frequently process data sensed from nearby devices as relevance is often dependent on proximity. Yet, today's services routinely use the client-server programming model which leads to sensed data being sent through the cellular network to a centralized server for processing. Harnessing the compute power of mobile devices to process data locally could ease bandwidth pressure on already overloaded cellular access networks and improve response times. Realizing this vision requires a way to easily program a collection of mobile devices connected over ad-hoc wireless. This paper presents DIstributed Programming Layer Over Mobile Agents (DIPLOMA), a programming layer and distributed shared memory system that provides coherent relaxed-consistency access to data residing on different mobile phones across a large geographic area. Our key insight is in translating the shared memory model from parallel computing to mobile computing, while addressing the unique challenges that mobility and unreliable wireless networking present in achieving consistency and coherence. We designed, prototyped and deployed DIPLOMA on 10 Android phones, evaluating it against another 10 phones running a conventional clientserver setup over both 3G(HSPA) and 4G(LTE) networks. On DIPLOMA, we implemented a Panoramio-like service as an example of a popular and representative location-based service, as well as a synthetic benchmark to measure response time, cellular bandwidth consumption, and power consumption. We also simulated large scale scenarios (up to 160 nodes) on the ns-2 network simulator. Compared to a client-server setup, our system shows response time improvements of 10x over 3G and 2x over 4G. We also observe cellular bandwidth reductions of 96%, comparable energy consumption, and a 95.3% request completion rate with coherent caching.

Original languageEnglish (US)
Title of host publication2012 IEEE 30th International Conference on Computer Design, ICCD 2012
Number of pages8
StatePublished - 2012
Event2012 IEEE 30th International Conference on Computer Design, ICCD 2012 - Montreal, QC, Canada
Duration: Sep 30 2012Oct 3 2012

Publication series

NameProceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors
ISSN (Print)1063-6404


Other2012 IEEE 30th International Conference on Computer Design, ICCD 2012
CityMontreal, QC

ASJC Scopus subject areas

  • Hardware and Architecture
  • Electrical and Electronic Engineering


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