In my early days in Perl on Windows, glob behaved in some undesireable fashion -- I no longer remember what the problems were.

You might try to isolate whether glob is causing the high CPU utilization -- I suspect it is NOT, but worth checking. You can replace glob with something like this:

# ... Create a regular expression to represent the wildcard string nor
+mally submitted to glob
my $MatchPatternRegex = "ABC\\_XYZ\\_.{9}\\.xml";
if (opendir CURDIR, $directoryName) {
    my $nextFilename = readdir CURDIR;
    while ($nextFilename)
    {
        if ($nextFilename =~ /$MatchPatternRegex/)
        {
            # ... Do your stuff here
        }
    }
    closedir CURDIR;
}
[download]

If using this instead of glob eliminates your CPU problem, you know something new about your environment, and perhaps you'll want to craft around glob. If this does not change the behavior, you've ruled out glob as the problem, which could be useful information as you troubleshoot this.