My Async::Event::Interval does this. It takes a callback as a parameter, and runs it at a given interval (in seconds). The callback is run in a separate process.

Example:

use warnings;
use strict;
use feature 'say';

use Async::Event::Interval;

my $delayed_event = Async::Event::Interval->new(5, \&interval_sub);

$delayed_event->start;

while (1) {
    say time;
    sleep 1;
}

sub interval_sub {
    say "Running interval sub";
}
[download]

Output:

1646160956
1646160957
1646160958
1646160959
1646160960
Running interval sub
1646160961
1646160962
1646160963
1646160964
1646160965
Running interval sub
1646160966
1646160967
1646160968
1646160969
1646160970
^C
[download]

An interval (first parameter to the new() method) of 0 (zero) will only run the routine once, but you can run it again at any time by calling $delayed_event->start if $delayed_event->waiting;. Floating point intervals are also supported if one needs such granularity.