Quality Time: A simple online technique for quantifying multicore execution efficiency

Anshuman Gupta, Jack Sampson, Michael Bedford Taylor

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

3 Scopus citations

Abstract

In order to increase utilization, multicore processors share memory resources among an increasing number of cores. This sharing leads to memory interference, which in turn leads to a non-uniform degradation in the execution of concurrent applications, even in the presence of fairness mechanisms. Many utilities rely on application CPU Time both for measuring resource usage and inferring application progress. These utilities are therefore directly affected by the distorting effects of multicore interference on the representativeness of CPU Time as a proxy for progress. This makes reasoning about myriad properties from fairness, to QoS, to throughput optimality very difficult in consolidated environments, such as IaaS. We introduce the notion of Quality Time, which provides a measure of application progress analogous to CPU Time's measure of resource usage, and we propose a simple online sampling-based technique to approximate Quality Time with high accuracy. We have implemented three user-space tools called Qtime, Qtop, and Qplacer. Qtime can attach to an application to calculate its Quality Time online, Qtop is a dashboard that monitors the Quality Times of all applications on the system, and Qplacer leverages Quality Time information to find better application placements and improve overall system quality. With Quality Time, we are able to reduce the error in inferring execution efficiency from 150.3% to 25.1% in the worst case and from 30.0% to 7.5% on average. Qplacer can increase average system throughput by 3.2% when compared to static application placement.

Original languageEnglish (US)
Title of host publicationISPASS 2014 - IEEE International Symposium on Performance Analysis of Systems and Software
PublisherIEEE Computer Society
Pages169-179
Number of pages11
ISBN (Print)9781479936052
DOIs
StatePublished - Jan 1 2014
Event2014 IEEE International Symposium on Performance Analysis of Systems and Software, ISPASS 2014 - Monterey, CA, United States
Duration: Mar 23 2014Mar 25 2014

Publication series

NameISPASS 2014 - IEEE International Symposium on Performance Analysis of Systems and Software

Other

Other2014 IEEE International Symposium on Performance Analysis of Systems and Software, ISPASS 2014
CountryUnited States
CityMonterey, CA
Period3/23/143/25/14

All Science Journal Classification (ASJC) codes

  • Software

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    Gupta, A., Sampson, J., & Taylor, M. B. (2014). Quality Time: A simple online technique for quantifying multicore execution efficiency. In ISPASS 2014 - IEEE International Symposium on Performance Analysis of Systems and Software (pp. 169-179). [6844481] (ISPASS 2014 - IEEE International Symposium on Performance Analysis of Systems and Software). IEEE Computer Society. https://doi.org/10.1109/ISPASS.2014.6844481