Does this script have the efficiency problems?

[Practical Perl]

Hello,

I have a script,which run well at most time.This day I use it to analyse the
files of 1.7G,it become very slow and can't get executed continuely
anymore.When I run 'strace -p xxxx' (here xxxx is this script's PID),there
is no output,it seems died.

Here is my script:

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

my $date=`date +%y%m%d`;
chomp $date;
my $dir="/home/datas/loginIP";    # here stored about 140 files,which are
totally 1.7G.
my @files= glob "$date/*.ip";
my (%low, %total);

foreach my $file (@files)
{
    open (FILE,$file) or die "$!";
        while(<FILE>)
        {
                next if /^192\.168\./;
                next unless /^(\d+\.\d+\.\d+\.)(\d+)/;
                $low{$1}{$2}=1 if $2 < 128;

                $total{$1}{$2}=1;
        }
        close FILE;
}


open (RESULT,">","dynamic.$date.re") or die "$!";

foreach (sort { scalar keys %{$total{$b}} <=> scalar keys %{$total{$a}} }
keys %total)
{
        my $low = scalar keys %{$low{$_}};
        my $high = (scalar keys %{$total{$_}}) - $low;

        if ($low > 64 and $high > 64)
        {
            printf RESULT "%-25s%-20s\n", $_."0", $_."255";
        }elsif ($low > 64 and $high <= 64)
        {
            printf RESULT "%-25s%-20s\n", $_."0", $_."127";
        }elsif ($low <= 64 and $high > 64)
        {
            printf RESULT "%-25s%-20s\n", $_."128", $_."255";
        }
}

close RESULT;

----

The files handled by the script are looked as:

211.139.227.247:3088
220.181.31.245:1134
220.181.31.247:1126
220.181.31.248:1120
220.181.31.246:1071
220.178.47.2:977
221.11.26.219:961
221.11.26.220:934
210.31.76.252:911
...
----
Why this happen and how to resolve it? Any suggestion is welcome.Thanks.