Post
Topic
Board Pools
Re: Looking for opinions of a replacement for ARS PPS if it dies
by
Meni Rosenfeld
on 12/12/2011, 17:02:44 UTC
If you want to know what's wrong with SMPPS you can have a look at section "Shared maximum pay-per-share (SMPPS)" (currently 4.2) of Analysis of Bitcoin Pooled Mining Reward Systems.
Put bluntly, this paper is wrong and biased:
    Arguing with you is futile, but I'll try. Obviously the paper is neither wrong nor biased.

    • MPPS does pay out fairly over the long-term to fair miners, at least in practice.
    You saying it doesn't make it true. Is there a factual error in what was written about MPPS?

    • While it is true that hoppers can hurt fair miners with MPPS, they have no incentive to do so. (remember that any pool can be hurt by the block withholding attack, so this is not a significant flaw)
    They do, it increases their expected payout and reduces its variance. I wasn't talking about block withholding.

    • SMPPS, in theory, will always drift toward 0-buffer 0-credit, it does not have any inherent negative drift.
    The drift is caused by external factors such as invalid blocks and withholding. In other methods these cause a decrease in profitability but not an expediting of a collapse.

    • In practice, SMPPS has proven to have a positive buffer much more than zero (on Eligius, we have only very briefly hit 0-buffer a few times)
    Look up "randomness". Just because Eligius' buffer had a certain manifested trajectory is very little evidence of anything.

    • While in theory, people might "hop" off SMPPS when it has no buffer, this is in practice not a problem. There was no mass exodus from Ars when its buffer hit zero and began issuing extra credit, and by now everyone has observed that so long as the pool remains online, it will eventually recover. Furthermore, this kind of "hopping" does not benefit the hopper nor harm the non-hopper.
    This kind of hopping does benefit the hopper and harm the non-hopper. Currently hoppers are busy with the proportional pools, they'll be happy to take advantage of SMPPS once those are gone. By your own admission the pool has only dipped in negative buffer area, so there was no observation of what happens when it is seriously negative.