Info: Zenodo’s user support line is staffed on regular business days between Dec 23 and Jan 5. Response times may be slightly longer than normal.

Published November 7, 2016 | Version v1
Conference paper Open

Superlinear speedup in HPC systems: Why and when?

  • 1. University of Innsbruck
  • 2. Skopje University
  • 3. Ruder Boškovic Institute

Description

The speedup is usually limited by two main laws in high-performance computing, that is, the Amdahl's and Gustafson's laws. However, the speedup sometimes can reach far beyond the limited linear speedup, known as superlinear speedup, which means that the speedup is greater than the number of processors that are used. Although the superlinear speedup is not a new concept and many authors have already reported its existence, most of them reported it as a side effect, without explaining why and how it is happening. In this paper, we analyze several different superlinear speedup types and define a taxonomy for them. Additionally, we present several explanations and cases of superlinearity existence for different types of granular algorithms (tasks), which means that they can be divided into many sub-tasks and scattered to the processors for execution. Apart from frequent explanation that having more cache memory in parallel execution is the main reason, we summarize other different effects that cause the superlinearity, including the superlinear speedup in cloud virtual environment for both vertical and horizontal scaling.

Files

FedCSIS2016.pdf

Files (349.4 kB)

Name Size Download all
md5:da8b9aa98fbc3bff374f7188fc72482f
349.4 kB Preview Download

Additional details

Funding

ENTICE – dEcentralized repositories for traNsparent and efficienT vIrtual maChine opErations 644179
European Commission