Not sure if my reply got posted properly.

Thanks again for your help

I did try something similar to this, but the problem I have is that I need the ping_hosts() sub to complete before the timer executes again, essentially blocking the timer. Thats why I had left $cv->recv; inside the ping_hosts() sub. Sorry I may have not made this clear.

From my basic understanding of event loops, this approach isn't going to work as there could be n+1 schedules blocking, I think I need to do something like whats described in http://www.perladvent.org/2014/2014-12-24.html replacing $cv->recv; with $cv->cb($callback); I'll keep plugging away but any assistance is much appreciated!