use file test.txt with 66060288 Byte
use existing File
preload file
Run Benchmark
                 Rate       read all read all seek      read push read push seek
read all       1.16/s             --            -1%            -1%           -2%
read push      1.17/s             1%             --            -0%           -1%
read push seek 1.17/s             1%             0%             --           -1%
read all seek  1.19/s             2%             1%             1%            --

#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw(cmpthese);

my $file='test.txt';
my $file_size=63*1024*1024; # 60MB
my $iter=10;

my $size=0;
$size = -s $file if(-f $file);

$/="\x0A";

print "use file $file with $file_size Byte\n";

# create file
if($size != $file_size)
{
  my $lines=int($file_size/81);

  print "create File ($lines lines and 81 chars per Line)\n";

  open(my $fh, '>', $file) or die("$file : $!\n");

  for(1..$lines)
  {
    print $fh join('',map{chr(int(rand(94))+32)}(1..80)).$/;
  }

  my $diff=$file_size-($lines*81);
  while($diff>0)
  {
    print $fh chr(int(rand(95))+32);
    $diff--;
  }

  close($fh);
}
else
{
  print "use existing File\n";
}

# loding file in OS-Filesystem-Cache:
print "preload file\n";
open(my $gfh, '<', $file) or die("$file : $!\n");
{
  local $/=undef;
  <$gfh>;
}

print "Run Benchmark\n";
cmpthese($iter, {
'read all' => sub{
    open(my $fh, '<', $file) or die("$file : $!\n");
    my @l=<$fh>;
    close($fh);
  },
'read push' => sub{
    open(my $fh, '<', $file) or die("$file : $!\n");
    my @l;
    while(<$fh>)
    { push(@l,$_); }
    close($fh);
  },
'read all seek' => sub{
    # goto file start
    seek($gfh,0,0);

    my @l=<$gfh>;
  },
'read push seek' => sub{
    # goto file start
    seek($gfh,0,0);

    my @l;
    while(<$gfh>)
    { push(@l,$_); }
  },

});

use file test.txt with 1048576 Byte
create File (12945 lines and 81 chars per Line)
preload file
Run Benchmark
                 Rate       read all      read push read push seek read all seek
read all       75.5/s             --            -1%            -2%           -3%
read push      76.2/s             1%             --            -1%           -2%
read push seek 77.0/s             2%             1%             --           -1%
read all seek  77.6/s             3%             2%             1%            --