#!/usr/bin/perl

use warnings;
use strict;

use DBI;
our $dbh = DBI->connect('DBI:mysql:database=test','db_user','db_pass')
    or die "Couldn't connect to db\n";
our $sth = $dbh->prepare("UPDATE counter SET count = count + ?")
    or die "Couldn't prepare statement\n";

foreach my $i(1..$ARGV[0]||100)
{
  my $r = add(1);
}

sub add
{
    $sth->execute($_[0])
        or die "Couldn't to SQL: $!\n";
}