#!/usr/bin/perl -sw

use strict;
use Benchmark;

our $ITERATIONS ||= 1e7;

timethese($ITERATIONS,
          {
           gmtime => sub {
             my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday) =
               gmtime(time);
           },
           localtime => sub {
             my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) 
+=
               localtime(time);
           },
          }
         );

__END__

$ perl 619744.pl
Benchmark: timing 10000000 iterations of localtime, gmtime...
 localtime: 101 wallclock secs (51.07 usr + 45.89 sys = 96.96 CPU) @ 1
+03135.31/s (n=10000000)
    gmtime: 62 wallclock secs (29.76 usr + 27.94 sys = 57.70 CPU) @ 17
+3310.23/s (n=10000000)
[download]

#!/usr/bin/perl -sw

use strict;
use Benchmark;
use Time::Local;

our $ITERATIONS ||= 1e7;

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday) =
    gmtime(time);

timethese($ITERATIONS,
          {
           timegm => sub {
                         my $time = timegm($sec,$min,$hour,$mday,$mon,
+$year);
           },
           timelocal => sub {
                         my $time = timelocal($sec,$min,$hour,$mday,$m
+on,$year);
           },
          }
         );

__END__

$ perl 619744.pl
Benchmark: timing 10000000 iterations of timegm, timelocal...
    timegm: 95 wallclock secs (89.95 usr +  0.06 sys = 90.01 CPU) @ 11
+1098.77/s (n=10000000)
 timelocal: 811 wallclock secs (654.30 usr + 112.15 sys = 766.45 CPU) 
+@ 13047.17/s (n=10000000)
[download]