The simple solution is Time::HiRes:

use Time::HiRes qw[ time sleep ];
...
$inotify->blocking(0);

my $end = time() + $timelimit;
while( time() < $end ) {
    for my $event ( $inotify->read ) {
        ## process event.
    }
    sleep 0.01; ## or 0.001 per your latency requirements
}
[download]

As for your fears about cpu usage. Polling once every hundredth or thousandth of a second, (much less every second), barely raises the usage at all. On my system, the usage is not discernible from zero to 2 decimal places.