fork,

my %kid;
for (1..10) {
    my $pid = fork;
    warn("Can't fork $_"), next if not defined $pid;
    $kid{$pid} = undef, next if $pid;
    undef %kid;
    exec qw/perl myscript.pl/;
}
delete $kid{+wait} while %kid;
[download]

# Now do some queries
for i in 1 2 3 4 5 6 7 8 9 10
do
  multihsh -p "_db=$CLASSNAME;_template=$TPLNAME" hsh 08stats.in >/dev
+/null &
done
 
for i in 1 2 3 4 5 6 7 8 9 10
do
  wait
  ec=$?
  if [ $ec -ne 0 ]
  then
    echo "A script exited with status $ec"
  fi
done
[download]

Here you go a complete stress test suite in 10 26 lines of perl :)

#! perl -slw
use strict; 
use threads; 
use LWP::Simple; 
use Time::HiRes qw[sleep];

$!=1; 

print "Usage $0 [-T=10] [-R=1.0] [-MAX=30] url" 
    unless $ARGV[ 0 ];

## Number of threads (simultaneuos callers)
our $T        ||= 10; 

## Fire rate in decimal seconds (0.1 once per 1/10 sec/thread)
our $R        ||= 1.0;  

## Seconds to sustain the burst.
our $MAX     ||= 30; 

async { 
    getprint( $ARGV[ 0 ] ) while sleep( rand( $R ) ); 
} for 1 .. $T;

sleep $MAX;
[download]

WARNING: Be careful who you aim it at!