Benchmark: timing 5 iterations of FastMktime::caching_mktime, POSIX::mktime, TIME::Local::timegm_nocheck... FastMktime::caching_mktime: 120 wallclock secs (120.21 usr + 0.05 sys = 120.26 CPU) @ 0.04/s (n=5) POSIX::mktime: 360 wallclock secs (165.42 usr + 193.81 sys = 359.23 CPU) @ 0.01/s (n=5) TIME::Local::timegm_nocheck: 293 wallclock secs (292.72 usr + 0.14 sys = 292.86 CPU) @ 0.02/s (n=5) #### Benchmark: timing 5 iterations of FastMktime::caching_mktime, POSIX::mktime, TIME::Local::timegm_nocheck... FastMktime::caching_mktime: 65 wallclock secs (64.77 usr + 0.02 sys = 64.79 CPU) @ 0.08/s (n=5) POSIX::mktime: 118 wallclock secs (58.16 usr + 60.47 sys = 118.63 CPU) @ 0.04/s (n=5) TIME::Local::timegm_nocheck: 143 wallclock secs (143.07 usr + 0.54 sys = 143.61 CPU) @ 0.03/s (n=5) #### #!/usr/bin/perl use FastMktime; use Benchmark qw(:all); use POSIX qw(mktime); use Time::Local; my $sstart = time; my $sstop = $sstart + 1e7; my @dates; # Stuff 1e7 sequential datestamps into an array. for (my $s=$sstart; $s<$sstop; $s++) { push(@dates, [ (gmtime $s)[0..5] ]); } my $tmp; my $results = timethese(1, { 'POSIX::mktime' => sub { $tmp = POSIX::mktime(@$_) for @dates }, 'TIME::Local::timegm_nocheck' => sub { $tmp = Time::Local::timegm_nocheck(@$_) for @dates }, 'FastMktime::caching_mktime' => sub { $tmp = FastMktime::caching_mktime(@$_) for @dates }, });