use strict;
use warnings;
use Benchmark;

our @strings = qw(exception:tex exception:mex asdf tex:exception:mex);

Benchmark::cmpthese( -5, {
    'one'   => q[ my @unfiltered = @strings; my @filtered = grep { /exception:(?!tex)/} @unfiltered; ],
    'two'   => q[ my @unfiltered = @strings; my @filtered = grep { /exception/ && !/tex/ } @unfiltered; ],
    'three' => q[ my @unfiltered = @strings; my @filtered = grep { /exception:/g && !/\Gtex/ } @unfiltered; ],
});
__END__
          Rate three   one   two
three  81985/s    --  -14%  -24%
one    95390/s   16%    --  -12%
two   108473/s   32%   14%    --