A quicky test shows that 3-arg substr is faster than chop, but a 4-arg substr is even faster - and that's to be expected because it saves a copy. Differences aren't dramatic though.

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

use Benchmark qw /cmpthese/;
                
chomp (our @strings = <DATA>);
                    
cmpthese -5 => {
    chop    => 'my @copy = @strings;
                foreach my $str (@copy) {
                    chop $str;
                    chop $str;
                    chop $str;
                    chop $str;
                }',
    substr3 => 'my @copy = @strings;
                foreach my $str (@copy) {
                    $str = substr $str => 0, -4;
                }',
    substr4 => 'my @copy = @strings;
                foreach my $str (@copy) {
                    substr $str => -4, 4 => "";
                }',
};
                
__DATA__
asdfjas;dfjas;dfjas;dkfjasdfasdf
asd
    
sdfajsd;flaks



            Rate    chop substr3 substr4
chop    152166/s      --    -11%    -14%
substr3 170187/s     12%      --     -4%
substr4 176800/s     16%      4%      --
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