$ perl -MTime::HiRes=time -E'
   for (;;) {
      my $s=time;
      system("sleep", "1");
      say time-$s;
   }
'
1.0089168548584
1.00794720649719
1.00801014900208
^C0.0198760032653809
^C0.180072069168091
^C0.147971153259277
...