You might be interested in this benchmark. It dosn't do exactly what you want, but it demonstrates the huge speed differences.

#!/usr/bin/perl
use Benchmark;
use File::ReadBackwards;
use strict;

my $numlines =10;
my $filename = 'talz.dat';  #some big file 

timethese(1000, {
#################################################### 
filereadbackwards => sub {
my @lines;
my $line;
my $count=0;
my $bw = File::ReadBackwards->new($filename) or
die "can't read filename $!" ;

while(defined($line = $bw->readline)){
push  @lines,$line ;
last if ++$count >= $numlines;
}
@lines= reverse @lines;
},
##################################################### 
tailz1 => sub {
    my $chunk = 400 * $numlines; #assume a <= 400 char line(generous) 
    # Open the file in read mode 
    open FILE, "<$filename" or die "Couldn't open $filename: $!";
    my $filesize = -s FILE;
    if($chunk >= $filesize){$chunk = $filesize}
    seek FILE,-$chunk,2; #get last chunk of bytes 

    my @tail = <FILE>;
    if($numlines >= $#tail +1){$numlines = $#tail +1}
    splice @tail, 0, @tail - $numlines;

},
});
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