Yeah I was wondering about that last night... You can see where I joined for a brief moment on the graph XD I was getting really inconsistent, low payouts though. Like every 30 min 0.02 888. Where as normally I get like 100+ an hour on a pool. So, not sure what the deal is with that, but meh XD

Payout logic

Each share contains a generation transaction that pays to the previous n shares, where n is the number of shares whose total work is equal to 3 times the average work required to solve a block, or 8640 (= 24 hours of shares), whichever is smaller. Payouts are weighted based on the amount of work each share took to solve, which is proportional to the p2pool difficulty at that time.

The block reward (currently 25BTC) and the transaction fees are combined and apportioned according to these rules:

A subsidy of 0.5% is sent to the node that solved the block in order to discourage not sharing solutions that qualify as a block. (A miner with the aim to harm others could withhold the block, thereby preventing anybody from getting paid. He can NOT redirect the payout to himself.) The remaining 99.5% is distributed evenly to miners based on work done recently.

In the event that a share qualifies as a block, this generation transaction is exposed to the Bitcoin network and takes effect, transferring each node its payout.
Stales

On P2Pool stales refer to shares which can't make it into the sharechain. Because the sharechain is 60 times faster than the Bitcoin chain many stales are common and expected. However, because the payout is PPLNS only your stale rate relative to other nodes is relevant; the absolute rate is not.

There are two reported kinds of stales in P2Pool: "DEAD ON ARRIVAL" shares and orphan shares. Dead shares were too old by the time they arrived at your local P2Pool. Very high dead rates can indicate miner misconfiguration. Orphan shares are shares which were not extended by the rest of the P2Pool network, because some other miner's share was accepted first. Very high orphan rates may indicate network connectivity problems.

The P2Pool console output shows your relative stale rate compared to other P2Pool miners in the 'Own efficiency' column:


When you first start P2Pool claimed efficiency will be low and the error bounds on this estimate will be large, but as it runs the numbers will converge to their correct values.

If your efficiency is unusually low, make sure your network connection isn't overloaded, that your miners support long polling and are not set to work for excessive amounts of time, and that your bitcoind has multiple connections.