What is actually happening when you

if (@sort_savepids ne @sort_livepids )
[download]

is that the arrays are getting interpreted in scalar context, which gives you the number of elements in the array.
Any two arrays with a different amount of elements will pass this test.

#!/usr/local/bin/perl
use strict;

my @s1 = qw( a b c );
my @s2 = qw( a b c );
my @s3 = qw( x y z );

print qq{s1 and s2 are equal\n} if ( @s1 eq @s2 );
print qq{s1 and s3 are equal(not really)\n} if ( @s1 eq @s3 );
[download]

Both statements will print out.

Wonko