Parallel Processing in SASCPUCOUNT

A comparison of Proc Means for the Project

THREADS and CPUCOUNT

• In SAS there is an option to let SAS create THREADS=YES, this allows SAS to start different threads that can be run on different CPUs.

• SAS also has an option to set the number of available CPUs, for example CPUCOUNT = 2

CPUCOUNT = 1 - 8

• The times to run the following code on the Project problem 2 were recorded for different CPUCOUNTs

proc means data=data01 n mean std maxdec=2;class location;title 'Mean scores for each location';var M1 - M8;

run;

CodeDM 'LOG;CLEAR;OUT;CLEAR';

OPTIONS THREADS=YES CPUCOUNT=8;

options mlogic mprint mtrace symbolgen;

data data01;

infile 'C:\Documents and Settings\Eric A. Suess\Desktop\Stat6250\data01.txt';

input ID Location M1 M2 M3 M4 M5 M6 M7 M8;

run;

/* Compute the mean and stdev of the measurement. */

proc means data=data01 n mean std maxdec=2;

class location;

title 'Mean scores for each location';

var M1 - M8;

run;

proc sort data=data01;

by location;

run;

proc means data=data01 n mean std maxdec=2;

by location;

title 'Mean scores for each location';

var M1 - M8;

run;

/* Create a new data set using the "output" subcommand. */

proc means data=data01 noprint nway;

class location;

var M1 - M8;

output out=locationsum

n = n_measurement

mean = m_measurement

std = s_measurement

max = max_measurement

min = min_measurement;

run;

proc print data=locationsum;

title 'Listing of data set locationsum';

run;

proc contents data=data01 ;

run;

For CPUCOUNT=7

419 /* Compute the mean and stdev of the measurement. */420 proc means data=data01 n mean std maxdec=2;421 class location;422 title 'Mean scores for each location';423 var M1 - M8;424 run;

NOTE: There were 3000000 observations read from the data set WORK.DATA01.

NOTE: PROCEDURE MEANS used (Total process time): real time 1.64 seconds cpu time 3.39 seconds

Times

CPUs real time cpu time

1 5.92 2.81

2 2.48 3.56

3 2.03 3.29

4 1.92 3.7

5 1.54 3.42

6 1.62 3.31

7 1.64 3.39

8 1.57 3.2

Graph

Proc Means times

0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8

CPUs

seco

nd

s

real time

cpu time

Question

• For what CPUCOUNT is there the most gain?

• After what number of CPUs is there no clear added advantage?