When the getblocktemplate latency started to appear, my efficiency was still between 110-115%. My getblocktemplate latency was about 30 seconds at that time.
This is the worst latency I've seen reported so far
My getblocktemplate latency hit about 30 seconds until I upgraded to the 0.8.2rc3.
Now I'm not sure if it's "bad luck" or something else but since I upgraded my latency is ~0.4 but my efficiency has been sitting in the low 80%s. I'm not quite sure how to debug this. My local DOA is ~2.5% but my orphans have been awful. I have both 8333 and 9333 traffic QOS'd. I guess I'm going to look closer at my network.
Check my guide if you see some low hanging fruits.
I just noticed that my own efficiency started to get down the last 24h (the first 24h with my settings where between 110 and 115% and now I'm at ~105%).
This may be because most P2Pool nodes are upgrading bitcoind and lowering their own getblocktemplate latency in the process. I'll have to test again to see if lowering my getblocktemplate latency helps my efficiency.
My current 0.25s might not be low enough now. One possibility is that this value actually influences efficiency when there's a noticeable difference between its value on a node and the average on all P2Pool nodes. Back to testing different bitcoin.conf values. Too bad: in its current configuration my node was including enough fees to make a 26.5BTC block! Fortunately with 0.8.2 I won't have to make much sacrifices in fees to reach very low latencies.