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#!/usr/bin/perl
# blockbench.pl - block-size benchmarking script
# DC3/DCCI
# Andrew Medico <andrew.medico.ctr@dc3.mil>
use strict;
use warnings;
use Getopt::Long;
my $num_trials = 3;
my $sectors = 10000;
my $dd = "/usr/local/bin/dc3dd";
my $help = 0;
my $res = GetOptions("trials=i" => \$num_trials,
"sectors=i" => \$sectors,
"dd=s" => \$dd,
"help" => \$help);
if ($help || not defined $ARGV[0])
{
print <<END;
Usage: $0 [OPTIONS] device
dc3dd Block Size Benchmark
This script attempts to find the optimum block size for drive imaging by trying
a range of block size values.
--dd=PATH Use dc3dd binary PATH [default: /usr/local/bin/dc3dd]
--trials=N Average the times of N trials [default: 3]
--sectors=N Read N sectors. Increase for fast devices if trials complete
too quickly for accurate timing, and decrease for slow devices
if trials take too long. [default: 10000]
--help Show this help
END
exit;
}
my $dev = $ARGV[0];
my $pc = $sectors * 10;
my @sizes = qw(512 1024 2048 4096 8192 16384 32768 65536 131072 262144 524288 1048576);
my %rates;
print "Testing $dev:\n";
print "Trials: $num_trials\n";
print "Sectors: $sectors\n";
print "\n";
my $direct_opt = "";
if ($^O !~ /darwin/i)
{
$direct_opt = "iflag=direct";
}
# for each candidate size
for my $size (@sizes)
{
print "bs=$size, trial";
my @trials;
# do multiple trials for a good average
for (1 .. $num_trials)
{
print " $_";
my $out = `$dd if=$dev of=/dev/null bs=$size $direct_opt conv=sync,noerror count=$sectors progresscount=$pc 2>&1`;
# 102400000 bytes (98 M) copied (100%), 0.803168 s, 122 M/s
if ($out =~ /(\d+) bytes .+ (\d+\.\d+) s/)
{
push(@trials, $1/$2);
}
else
{
die "\ndc3dd execution failed - output was:\n$out\n";
}
}
print "\n";
$rates{$size} = average(@trials);
}
print "\nResults:\n";
my ($bs, $rate, $speedup);
format STDOUT =
bs=@#######, avg rate @######### B/s (@#X)
$bs, $rate, $speedup
.
my $base = $rates{512};
for $bs (sort {$rates{$b} <=> $rates{$a}} keys %rates)
{
$rate = $rates{$bs};
$speedup = $rate / $base;
write;
}
sub average
{
my $total = 0;
map { $total += $_} @_;
return $total / ($#_+1);
}
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