perlでミリ秒を求める

get_milliseconds.pl

use Time::HiRes;

my $num = 0;

##### gettimeofday() は、1つ目の要素が整数秒、2つ目の要素が小数点以下の数値である配列を返す
my $start_time = join '.', Time::HiRes::gettimeofday;
while ( $num < 10000000 ) {
    print $num++, "\n";
}
my $end_time = join '.', Time::HiRes::gettimeofday;

my $diff = $end_time - $start_time;

print "costs : ${diff}\n";