According to this comment>>http://wordpress.org/support/topic/p2-high-load-server-shared-enviromnt?replies=14#post-5298637
P2 (and currently o2) just isn’t going to deal that well with lots and lots of users [even if not logged in], all accessing the site at the same time, especially on a shared host. Each user who has a P2/o2 window open is continuously polling the server, so they’re effectively sitting there hitting refresh.
I have few questions about this"
1. "Each user who has a P2/o2 window open is continuously polling the server." <-- This doesn't apply to viewing permalink/single post I presume?
2. In a child theme, I would like to turn off refreshing/polling for non-logged in users. What's the best way to go about it?