use strict; use warnings;
my $begin;
BEGIN { chop( $begin = `ps -o vsz= $$` )}

eval "sub F_$_ {
    my( \$a, \$b, \$c ) = \@_; 
    my \$x = $_; 
    return \$a * \$b - (\$x + \$c); 
}" for 1..1e4;

END {
    chop( my $end = `ps -o vsz= $$` );
    print "$end - $begin = ",$end - $begin, "\n";
}
__END__
60924 -  22228 = 38696