I added a blank line to your data, and removed some data lines for simplicity. I know you said you wanted to use regex instead of split, but I do not understand why. Is this what you are trying to achieve?

#!/usr/bin/env perl

use strict;
use warnings;
while ( <DATA> ) {
    next if /^HOSTNAME/; # skip title line
    next if /^\-/;       # skip lines which start with "-"
    s/^\s+//;            # remove whitespace at start of line
    s/\s+$//;            # remove whitespace at end   of line
    next if /^$/;        # skip blank lines
    my ($host, $arch, $proc, $load, $memtot, $memuse, $swap, $swapuse 
+) = split;
    print "Using split function Host is $host\n";
}
__DATA__
HOSTNAME             ARCH       NPROC  LOAD   MEMTOT   MEMUSE   SWAPTO
+   SWAPUS
----------------------------------------------------------------------
+---------
global               -              -     -        -        -        -
+        -
Luke                 glinux         2  0.70     3.4G   919.5M     1.9G
+   681.6M
bobafett             glinux         2  0.00     3.4G   205.8M     1.9G
+      0.0

bones                glinux         2  0.01     2.0G   150.9M     1.9G
+      0.0
c3p0                 glinux         2  0.37     3.4G   101.6M     1.9G
+     7.2M
dax                  glinux         4  0.81     2.0G   438.0M     1.9G
+   272.1M
geordi               glinux         4     -     2.0G        -     1.9G
+        -
han                  glinux         2  0.53     3.4G   373.6M     1.9G
+   243.3M
janeway              glinux         2  0.00     7.3G   351.9M    16.0G
+      0.0
lando                glinux         4  1.27     7.3G   445.8M     1.9G
+     6.9M
sisko                glinux         2     -     2.0G        -     1.9G
+        -
sulu                 glinux         2     -   493.7M        -  1019.7M
+        -
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gives me this output:

Using split function Host is global
Using split function Host is Luke
Using split function Host is bobafett
Using split function Host is bones
Using split function Host is c3p0
Using split function Host is dax
Using split function Host is geordi
Using split function Host is han
Using split function Host is janeway
Using split function Host is lando
Using split function Host is sisko
Using split function Host is sulu
[download]