gistfile1.txt

use Benchmark qw/cmpthese/;                                                                                                                                                          
                                                                                                                                                                                     
                                                                                                                                                                                     
my $hash = +{                                                                                                                                                                        
    id => 123,                                                                                                                                                                       
    mail => 'chiba@everqueue.com',                                                                                                                                                   
};                                                                                                                                                                                   
my @keys = qw/id mail/;                                                                                                                                                              
                                                                                                                                                                                     
cmpthese(-1, {                                                                                                                                                                       
    slice => sub {                                                                                                                                                                   
        join ', ', @$hash{@keys};                                                                                                                                                    
    },                                                                                                                                                                               
    map  => sub {                                                                                                                                                                    
        join ', ', map { $hash->{$_} } @keys;                                                                                                                                        
    },                                                                                                                                                                               
});                                                                                                                                                                                  
                                                                                                                                                                                     

==============================
           Rate   map slice
map    771011/s    --  -60%
slice 1927529/s  150%    --