I get slightly different results: 

$ perl -le'
open D, q[/usr/share/dict/words] or die $!;
my $string = join "|", <D>;
use Benchmark qw/cmpthese/;
cmpthese -20, {
    orig => sub {
        my @arr = split /\|/, $string;
        my @arr1 = grep { /oug/ } @arr;
        return @arr1;
        },
    Buk1 => sub {
        my @arr1 = grep { /oug/ } split /\|/, $string;
        return @arr1;
        },
    jwkrahn => sub {
        my @arr1 = grep /oug/, split /\|/, $string;
        return @arr1;
        },
    Buk2 => sub {
        my @arr1 = $string =~ /(?:^|\|)(.*?oug.*?)(?=\||$)/g;
        return @arr1;
        },
    JOOST => sub {
        my @arr1 = $string =~ /(?:^|\|)([^|]*?oug[^|]*?)(?=\||$)/g;
        return @arr1;
        },
    };
'
          Rate   JOOST    Buk2    orig    Buk1 jwkrahn
JOOST   4.37/s      --    -10%    -13%    -38%    -67%
Buk2    4.87/s     11%      --     -4%    -31%    -63%
orig    5.05/s     15%      4%      --    -28%    -62%
Buk1    7.05/s     61%     45%     40%      --    -47%
jwkrahn 13.2/s    202%    171%    162%     87%      --

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  YMMV   :-)

In reply to Re^4: Performance optimization question by jwkrahn
in thread Performance optimization question by vit

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