use Benchmark qw{ timethese };

timethese( -2, {
	Ordinary => q{
		my @results = sort { -M $a <=> -M $b } glob "/bin/*";
		},
	Schwartzian => q{
		map $_->[0],
		sort { $a->[1] <=> $b->[1] }
		map [$_, -M],
		glob "/bin/*";
		},
	});

##</code><code>##

#!/usr/bin/perl
use strict;

use Benchmark;

$L::glob  = "/usr/local/*/*";
@L::files = glob $L::glob;

print "Testing with " . @L::files . " files\n";

my $transform = 
	q|map $_->[0], sort { $a->[1] <=> $b->[1] } map [ $_, -M ]|;
my $sort      = q|sort { -M $a <=> -M $b }|;

my $code = {
 assign               =>  q| my @r       = @L::files              |,
 'glob'               =>  q| my @files   = glob $L::glob          |,
	
 sort_names           =>  q| sort { $a cmp $b } @L::files         |,
 sort_names_assign    =>  q| my @r = sort { $a cmp $b } @L::files |,
 sort_times_assign    =>  q| my @r = $sort              @L::files |,
	
 ordinary_orig        => qq| my \@r = $sort glob \$L::glob        |,
 ordinary_mod         => qq| my \@r = $sort      \@L::files       |,
	
 schwartz_orig        => qq|          $transform, glob \$L::glob  |,
 schwartz_orig_assign => qq| my \@r = $transform, glob \$L::glob  |,
 schwartz_mod         => qq| my \@r = $transform, \@L::files      |,
 } ;

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
print "Timing for 2 CPU seconds...\n";

timethese( -2, $code );

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
my $iterations = 1_000;

print "-" x 73, "\n";
print "Timing for $iterations iterations\n";

timethese( $iterations, $code );

##</code><code>##

albook_brian[519]$ perl benchmark
Testing with 380 files
Timing for 2 CPU seconds...
Benchmark: running assign, glob, ordinary_mod, ordinary_orig, schwartz_mod, schwartz_orig, 
	schwartz_orig_assign, sort_names, sort_names_assign for at least 2 CPU seconds...
    assign:            (2.03 usr + 0.00 sys = 2.03 CPU) (n=   6063)
      glob:            (0.81 usr + 1.27 sys = 2.08 CPU) (n=    372)
ordinary_mod:          (0.46 usr + 1.70 sys = 2.16 CPU) (n=     80)
ordinary_orig:         (0.51 usr + 1.64 sys = 2.15 CPU) (n=     66)
schwartz_mod:          (1.54 usr + 0.51 sys = 2.05 CPU) (n=    271)
schwartz_orig:         (1.06 usr + 1.03 sys = 2.09 CPU) (n=    174)
schwartz_orig_assign:  (1.20 usr + 0.87 sys = 2.07 CPU) (n=    156)
sort_names:            (2.09 usr + 0.01 sys = 2.10 CPU) (n=3595626)
sort_names_assign:     (2.16 usr + 0.00 sys = 2.16 CPU) (n=   5698)
-------------------------------------------------------------------------
Timing for 1000 iterations
Benchmark: timing 1000 iterations of assign, glob, ordinary_mod, ordinary_orig, schwartz_mod, 
	schwartz_orig, schwartz_orig_assign, sort_names, sort_names_assign...
    assign:            1 secs ( 0.33 usr +  0.00 sys =  0.33 CPU) 
      glob:            6 secs ( 2.31 usr +  3.30 sys =  5.61 CPU) 
ordinary_mod:         28 secs ( 5.57 usr + 21.49 sys = 27.06 CPU) 
ordinary_orig:        34 secs ( 7.86 usr + 24.74 sys = 32.60 CPU) 
schwartz_mod:          8 secs ( 5.12 usr +  2.47 sys =  7.59 CPU) 
schwartz_orig:        12 secs ( 6.63 usr +  5.52 sys = 12.15 CPU) 
schwartz_orig_assign: 14 secs ( 7.76 usr +  5.41 sys = 13.17 CPU) 
sort_names:            0 secs ( 0.00 usr +  0.00 sys =  0.00 CPU)
sort_names_assign:     0 secs ( 0.39 usr +  0.00 sys =  0.39 CPU) 

##</code><code>##

Benchmark: timing 1000 iterations of glob, ordinary_mod, schwartz_mod, schwartz_orig_assign...
      glob:           14 secs ( 6.28 usr +  8.00 sys = 14.28 CPU) 
ordinary_mod:         73 secs (14.25 usr + 57.05 sys = 71.30 CPU) 
ordinary_orig:        93 secs (20.83 usr + 66.14 sys = 86.97 CPU) 
schwartz_mod:         20 secs (14.06 usr +  5.52 sys = 19.58 CPU) 
schwartz_orig:        32 secs (17.38 usr + 13.59 sys = 30.97 CPU) 
schwartz_orig_assign: 34 secs (19.95 usr + 13.60 sys = 33.55 CPU) 

##</code><code>##

Benchmark: timing 1000 iterations of glob, ordinary_mod, schwartz_mod, schwartz_orig_assign...
      glob:           148 secs ( 31.26 usr + 102.59 sys = 133.85 CPU) 
ordinary_mod:         675 secs ( 86.64 usr + 517.19 sys = 603.83 CPU) 
ordinary_orig:        825 secs (116.55 usr + 617.62 sys = 734.17 CPU) 
schwartz_mod:         151 secs ( 68.88 usr +  67.32 sys = 136.20 CPU) 
schwartz_orig:        297 secs ( 89.33 usr + 174.51 sys = 263.84 CPU) 
schwartz_orig_assign: 294 secs ( 96.68 usr + 168.76 sys = 265.44 CPU)