### Yang You, James Demmel, Kenneth Czechowski, Le Song and Richard Vuduc

###
EECS Department

University of California, Berkeley

Technical Report No. UCB/EECS-2015-9

February 27, 2015

### http://www2.eecs.berkeley.edu/Pubs/TechRpts/2015/EECS-2015-9.pdf

We consider the problem of how to design and implement communication-efficient versions of parallel support vector machines, a widely used classifier in statistical machine learning, for distributed memory clusters and supercomputers. The main computational bottleneck is the training phase, in which a statistical model is built from an input data set. Prior to our study, the parallel isoefficiency of a state-of-the-art implementation scaled as W = Omega(P^3), where W is the problem size and P the number of processors; this scaling is worse than even a one-dimensional block row dense matrix vector multiplication, which has W = Omega(P^2). This study considers a series of algorithmic refinements, leading ultimately to a Communication-Avoiding SVM (CASVM) method that improves the isoefficiency to nearly W = Omega(P). We evaluate these methods on 96 to 1536 processors, and show average speedups of 3 - 16x (7x on average) over Dis-SMO, and a 95% weak-scaling efficiency on six realworld datasets, with only modest losses in overall classification accuracy. The source code can be downloaded at [1].

BibTeX citation:

@techreport{You:EECS-2015-9, Author = {You, Yang and Demmel, James and Czechowski, Kenneth and Song, Le and Vuduc, Richard}, Title = {CA-SVM: Communication-Avoiding Parallel Support Vector Machines on Distributed Systems}, Institution = {EECS Department, University of California, Berkeley}, Year = {2015}, Month = {Feb}, URL = {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2015/EECS-2015-9.html}, Number = {UCB/EECS-2015-9}, Abstract = {We consider the problem of how to design and implement communication-efficient versions of parallel support vector machines, a widely used classifier in statistical machine learning, for distributed memory clusters and supercomputers. The main computational bottleneck is the training phase, in which a statistical model is built from an input data set. Prior to our study, the parallel isoefficiency of a state-of-the-art implementation scaled as W = Omega(P^3), where W is the problem size and P the number of processors; this scaling is worse than even a one-dimensional block row dense matrix vector multiplication, which has W = Omega(P^2). This study considers a series of algorithmic refinements, leading ultimately to a Communication-Avoiding SVM (CASVM) method that improves the isoefficiency to nearly W = Omega(P). We evaluate these methods on 96 to 1536 processors, and show average speedups of 3 - 16x (7x on average) over Dis-SMO, and a 95% weak-scaling efficiency on six realworld datasets, with only modest losses in overall classification accuracy. The source code can be downloaded at [1].} }

EndNote citation:

%0 Report %A You, Yang %A Demmel, James %A Czechowski, Kenneth %A Song, Le %A Vuduc, Richard %T CA-SVM: Communication-Avoiding Parallel Support Vector Machines on Distributed Systems %I EECS Department, University of California, Berkeley %D 2015 %8 February 27 %@ UCB/EECS-2015-9 %U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2015/EECS-2015-9.html %F You:EECS-2015-9