#!/usr/bin/perl -w
use strict;
 
use Benchmark;
 
opendir LOGS, ".";
my @logs = readdir LOGS;
 
my $cmp = timethese( -1, {
  'Cached' => sub{
   my @sorted = map   { $_->[0] }
                sort  { $a->[1] <=> $b->[1] }
                map   { [$_, -M $_] }
#                grep  { /\.log$/ }
                @logs;
  },
 'Raw' => sub {
   my @sorted = sort  { -M $a <=> -M $b }
#                grep  { /\.log$/ }
                @logs;
  }
 }
);
 
Benchmark::cmpthese( $cmp );

##</code><code>##

Benchmark: running Cached, Raw, each for at least 1 CPU seconds...
    Cached:  2 wallclock secs ( 0.90 usr +  0.15 sys =  1.05 CPU) @ 18.10/s (n=19)
       Raw:  2 wallclock secs ( 0.45 usr +  0.64 sys =  1.09 CPU) @  8.26/s (n=9)
         Rate    Raw Cached
Raw    8.26/s     --   -54%
Cached 18.1/s   119%     --

#that's too little iterations....

Benchmark: timing 1000 iterations of Cached, Raw...
    Cached: 105 wallclock secs (44.91 usr +  7.74 sys = 52.65 CPU) @ 18.99/s (n=1000)
       Raw: 258 wallclock secs (47.15 usr + 78.43 sys = 125.58 CPU) @  7.96/s (n=1000)
         Rate    Raw Cached
Raw    7.96/s     --   -58%
Cached 19.0/s   139%     --