use Time::HiRes qw( sleep );

my $interval = 3;
my $min_sleep = 0;

my $sleep_until = time;
while (1) {
   work();

   $sleep_until += $interval;
   my $now = time;
   my $sleep_for = $sleep_until - $now;
   if ($sleep_for < $min_sleep) {
      warn("Work took too long\n");
      $sleep_for = $min_sleep;
      $sleep_until = $now + $sleep_for;
   }

   sleep($sleep_for) if $sleep_for;
}
[download]