Links

From CSI 702

1 Links

• Details on gcc optimization:

http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html

2 Other Stuff

2.1 Timing Script

"A Timing Script", a quick perl script for running a program x number of times and getting the average running time and standard deviation on the running time. On a linux machine, copy the code below into a file named "ats.pl". Then run "chmod +x ats.pl". Examples of usage:

./ats.pl 5 command arg1 arg2 arg3

or

./ats.pl 3 echo "hiho"
Loop   Time
0      0.0
1      0.0
2      0.0
AVG    0.000
DEV    0.000

Feel free to alter this code as you please or drop me an email if you have any comments/questsions.

#!/usr/bin/perl
#A Timing Script
#Send support questions here-> adamcadien 'at' gmail 'dot' com
#Usage: ./ats.pl <#runs> <executable name> <arguements>

use strict;

if(@ARGV<3){
    print "ats.pl wasn't used properly\n";
    print "usage: ./ats.pl <#runs> <executable name> <arguements>\n";
    exit;
}

my $looplen=shift;
my $script=shift;
my $args;
while ($_=shift){
    $args.=$_." ";
}

print "Command: ./$script $args\n";

my $avg=0;
my @stats;
print "Loop\tTime\n";
foreach my $i (0..$looplen-1) {
    my $res=`/usr/bin/time ./$script $args 2>&1`;
    if($res =~ /(\d\.\d\d)user/){
        push @stats,$1;
	$avg+=$1;
	print "$i\t$1\n";
    }  
}
$avg/=$looplen;
printf("AVG\t%3.3f\n",$avg);

my $sdv;
foreach my $i (@stats){
    $sdv+=($i-$avg)**2;
}
$sdv/=$looplen;
$sdv=sqrt $sdv;
printf("DEV\t%3.3f\n",$sdv);