sub by_cpu {
    no warnings 'numeric';
    $passes->{$a}{cpu} <=> $passes->{$b}{cpu};
}
for my $tc (sort by_cpu keys %$passes) {
    # ...

##</code><code>##

my @dashed;
my @sorted = sort { $passes->{$a}{cpu} <=> $passes->{$b}{cpu} }
             grep { '-' ne $passes->{$_}{cpu}
                    or push @dashed, $_ and 0
             } keys %$passes;
for my $tc (@dashed, @sorted) {
    # ...