This is easy to do, though I agree there may well be better ways of solving the real problem:

#! perl -slw
use strict;
use threads;
use threads::shared;

my $quit :shared = 0;

$SIG{INT} = sub {
    print 'SIGINT';
    $quit = 1;
};

async {
    while( not $quit ) {
        my $wakeup = time() + 60 * 60;
        print( $quit ), sleep 1 while not $quit and time() < $wakeup;
        ## Do the hourly task;
    }
}->detach;

sleep 1 while not $quit;

__END__
c:\test>junk60
0
0
SIGINT
[download]

The cpu cost of waking once per second is nominal.