#! /usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use Time::HiRes qw{ time sleep };

sub func { sleep rand 0.05 }

my $t0 = 0;
while (1) {
    if (time - $t0 >= 0.1) {
        say $t0 = time;
        func();
    }
}