i benchmarked the binmode variant against the utf8 open variant down here. i made an xml file with 100 lines and 32000 ü's (utf8) in each line ((P)CDATA). the below script did it in 0.20 seconds while the 'use utf8; / binmode' method take about 17.5 seconds.

unfortunately perl crashes when i give a filehande to the parser while using the 'use open qw/:std :utf8/;' method when the file gets big. the 'use utf8; / binmode' method takes about 35 seconds when i pass the filehandle to the parser.

output got redirected to /dev/null

#!/usr/bin/perl

use XML::Parser;
#use utf8;
use open qw/:std :utf8/;

$ch = sub {
    my ($p, $w) = @_;
#    binmode STDOUT, ":encoding(UTF-8)";
    print "$w\n";
};

$p = XML::Parser->new(ProtocolEncoding => 'UTF-8');
$p->setHandlers('Char' => $ch);


my $xml = "";
open(F, '< x.xml');
while(<F>) { $xml .= $_; }

$p->parse($xml);
#$p->parse(*F);
close(F);
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