# Perfect strong scaling using no additional energy

### James Demmel, Andrew Gearhart, Oded Schwartz and Benjamin Lipshitz

###
EECS Department

University of California, Berkeley

Technical Report No. UCB/EECS-2012-126

May 30, 2012

### http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-126.pdf

Energy efficiency of computing devices has become a dominant area of research interest in recent years. Most of this work is focused on architectural techniques to improve power and energy efficiency; only a few consider saving energy at the algorithmic level. We prove that a region of perfect strong scaling in energy exists for matrix multiplication (classical and Strassen) and the direct (O(n2)) n-body problem via the use of .5D algorithms: This means that we can increase the number of processors by a constant factor, with the runtime (both computation and communication) decreasing by the same factor, and the total energy used remaining constant.

BibTeX citation:

@techreport{Demmel:EECS-2012-126, Author = {Demmel, James and Gearhart, Andrew and Schwartz, Oded and Lipshitz, Benjamin}, Title = {Perfect strong scaling using no additional energy}, Institution = {EECS Department, University of California, Berkeley}, Year = {2012}, Month = {May}, URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-126.html}, Number = {UCB/EECS-2012-126}, Abstract = {Energy efficiency of computing devices has become a dominant area of research interest in recent years. Most of this work is focused on architectural techniques to improve power and energy efficiency; only a few consider saving energy at the algorithmic level. We prove that a region of perfect strong scaling in energy exists for matrix multiplication (classical and Strassen) and the direct (O(n2)) n-body problem via the use of .5D algorithms: This means that we can increase the number of processors by a constant factor, with the runtime (both computation and communication) decreasing by the same factor, and the total energy used remaining constant.} }

EndNote citation:

%0 Report %A Demmel, James %A Gearhart, Andrew %A Schwartz, Oded %A Lipshitz, Benjamin %T Perfect strong scaling using no additional energy %I EECS Department, University of California, Berkeley %D 2012 %8 May 30 %@ UCB/EECS-2012-126 %U http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-126.html %F Demmel:EECS-2012-126