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Author Topic: [1500 TH] p2pool: Decentralized, DoS-resistant, Hop-Proof pool  (Read 2029108 times)
drazah
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June 13, 2016, 04:26:17 PM
 #14581

Im just getting back into mining and i picked up two cheap S4s (i get free electricity) and from the pools that i looked at to go into, 3% does seem really high to me.

It is not hard to get a better rate than 3%.

https://kano.is/ is 0.9%
https://bitminter.com/ is 1%
https://slushpool.com/ is 2%

Thats exactly what i mean, there was no issue finding a good pool under 3%, even 1% or lower. (currently @ kano ck)
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June 13, 2016, 04:57:21 PM
 #14582


It is not hard to get a better rate than 3%.

https://kano.is/ is 0.9%
https://bitminter.com/ is 1%
https://slushpool.com/ is 2%

LMFTFY Wink

P2Pool is 0% with transaction fees paid to miners.

And as a side note, Kano has managed to change this into a thread for promoting his pool AGAIN....

This thread is about P2Pool, lets please keep it focused.
What? Not willing to actually say what the average P2Pool Txn fees have been for the last 100 blocks?
Would be rather odd to be saying ... "Rewards are better here coz you expect to be paid less ..."

At least quote the numbers that are relevant: 0% fee, X% txn fees, Y% orphans
Or is that not gonna give you the answer you want to tell everyone?

That's another thing that sets P2Pool apart from centralized, trust requiring mining farms like yours, 100% transparency, thanks for reminding me!

Here's all the data for P2Pool since inception:  http://minefast.coincadence.com/p2pool-stats.php



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June 13, 2016, 11:27:02 PM
 #14583


It is not hard to get a better rate than 3%.

https://kano.is/ is 0.9%
https://bitminter.com/ is 1%
https://slushpool.com/ is 2%

LMFTFY Wink

P2Pool is 0% with transaction fees paid to miners.

And as a side note, Kano has managed to change this into a thread for promoting his pool AGAIN....

This thread is about P2Pool, lets please keep it focused.
What? Not willing to actually say what the average P2Pool Txn fees have been for the last 100 blocks?
Would be rather odd to be saying ... "Rewards are better here coz you expect to be paid less ..."

At least quote the numbers that are relevant: 0% fee, X% txn fees, Y% orphans
Or is that not gonna give you the answer you want to tell everyone?

That's another thing that sets P2Pool apart from centralized, trust requiring mining farms like yours, 100% transparency, thanks for reminding me!

Here's all the data for P2Pool since inception:  http://minefast.coincadence.com/p2pool-stats.php

You still wont say the numbers hey. Why? Smiley

Pool: https://kano.is BTC: 1KanoiBupPiZfkwqB7rfLXAzPnoTshAVmb
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Help keep Bitcoin secure by mining on pools with Stratum, the best protocol to mine Bitcoins with ASIC hardware
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June 13, 2016, 11:38:59 PM
 #14584

And as a side note, Kano has managed to change this into a thread for promoting his pool AGAIN....

It is shocking how much time he spends trolling.

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June 14, 2016, 12:01:03 AM
 #14585

And as a side note, Kano has managed to change this into a thread for promoting his pool AGAIN....

It is shocking how much time he spends trolling.
Pointing out that Toomin's numbers were crap exaggeration is trolling?
Oh well then go blow him and feel good about it.

Pool: https://kano.is BTC: 1KanoiBupPiZfkwqB7rfLXAzPnoTshAVmb
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Help keep Bitcoin secure by mining on pools with Stratum, the best protocol to mine Bitcoins with ASIC hardware
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June 14, 2016, 03:09:25 AM
 #14586

p2pool node scanner has been updated: http://p2pool.co

Please send any more updates and let me know how we can make it better.

Find the pool with the best payout!
nodes.p2pool.co
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June 14, 2016, 08:02:33 AM
 #14587

And as a side note, Kano has managed to change this into a thread for promoting his pool AGAIN....

It is shocking how much time he spends trolling.

Pointing out that Toomin's numbers were crap exaggeration is trolling?
<removed homosexual nonsense>

You have a reading comprehension problem.

Where on the doll did p2pool touch you?



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in2tactics
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June 14, 2016, 11:50:48 AM
 #14588

Where on the doll did p2pool touch you?



This is worth at least one or two small chuckles.

Active... 2x AntMiner S7-LN, 4x AntMiner S3, and 5x AntMiner U1
Collecting Dust... 2x ASICMiner Block Erupter Cube, 4x AntMiner S1, GAW Black Widow, and ZeusMiner Thunder X6
Needing RMA (but too lazy)... 2x R9 280x and 2x R7 270x // Coin Interests... BTC, LTC, DOGE
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June 15, 2016, 11:24:12 PM
 #14589

Good news: The Antminer S9 works fine on p2pool with no modifications. I've been running mine on p2pool for the last 8 hours, and it's producing within 1% of the hashrate that I saw when I tested it on a traditional pool.

Hosting bitcoin miners for $75 to $90/kW/month on clean, cheap hydro power.
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June 16, 2016, 06:57:23 AM
 #14590

Good news: The Antminer S9 works fine on p2pool with no modifications. I've been running mine on p2pool for the last 8 hours, and it's producing within 1% of the hashrate that I saw when I tested it on a traditional pool.

That is really fantastic news. Let's hope we get a lot more of those beasts up on p2pool soon.

I was considering restarting my modest (well under 1 MW) but, despite claims of full and forced industrialization and centralization, economically-viable Bitcoin mining operation after reviewing the initial S9 announcement but for largely unrelated reasons decided to wait for a later batch. When I deploy them it will almost certainly be on p2pool.
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June 16, 2016, 07:00:56 AM
 #14591

However, there is no need to have miners switch work once per share. Bitcoin's blocks and transactions need to be serialized in a canonical ordering in order to prevent double-spending or transaction conflicts, but with p2pool there's no equivalent need for each share to come one after another. All that a share needs to do is prove that work was done in a way that benefits other p2pool users, which means (a) accurately pays out to other p2pool users and (b) is working on the correct block height at any given time.

How do you implement PPLNS without consensus on the order of shares?

I think when you make this kind of change to allow sibling shares you will need to introduce more complex incentive models to try to make the payouts "fair" and unexploitable (including hop-proof), not unlike how GHOST or ETH's version of it attempt to do so with block rewards. That sounds like a mess.

In any case I'm glad to hear that firmware issues seem to be resolved on the latest Antminers, potentially reducing the need for this.
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June 16, 2016, 07:53:28 AM
 #14592

How do you implement PPLNS without consensus on the order of shares?
The shares are partially ordered. Each share has a height associated with it determined by the share's parent. In a share chain, each share that makes it into the final chain has a different height. In a share DAG, multiple shares can have the same height. With both, for PPNLS you reward all shares where share_height >= chain_tip_height - N.

I think when you make this kind of change to allow sibling shares you will need to introduce more complex incentive models to try to make the payouts "fair" and unexploitable (including hop-proof), not unlike how GHOST or ETH's version of it attempt to do so with block rewards. That sounds like a mess.
Yes, the analysis of incentives is more complex. I haven't seen any ways in which DAGs could incentivize hopping, as it's still PPLNS and expected reward is independent of the work done since the last block was found. However, there are some potential issues regarding selfish mining on the share DAG with some DAG reward algorithms. I think they aren't too difficult to solve, but it's true that care is required.

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June 16, 2016, 12:06:51 PM
 #14593

I haven't seen any ways in which DAGs could incentivize hopping, as it's still PPLNS and expected reward is independent of the work done since the last block was found.

It is not. With the scheme as described the split factor for block rewards is not constant (ignoring difficulty changes) as it is for PPLNS (i.e. 1/N). More shares at the same height means rewards split more ways, which reduces the expectation for a winning share. This is in some way analogous to PPS, and will uncover similar problems.
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June 16, 2016, 02:18:39 PM
 #14594

I haven't seen any ways in which DAGs could incentivize hopping, as it's still PPLNS and expected reward is independent of the work done since the last block was found.
It is not. With the scheme as described the split factor for block rewards is not constant (ignoring difficulty changes) as it is for PPLNS (i.e. 1/N). More shares at the same height means rewards split more ways, which reduces the expectation for a winning share. This is in some way analogous to PPS, and will uncover similar problems.
To clarify, expected reward for a share is independent of the work done since the last block was found. If there are more shares per DAG level/height, that means that your share will stay in the last N height for a longer amount of time, so it will have a greater probability of being rewarded, but the reward will be smaller.

Let M equal the number of shares in the last N levels of the DAG. The average number of shares per level is M/N. Assume all shares have equal difficulty for now, and assume steady-state conditions, where M stays roughly constant for a single share's transit through the last N levels. Should a block be found, each share's reward will be 1/M. The probability that a block will be found depends on the amount of work done among those M shares. Since all shares have equal difficulty, that means that the probability of a block being found will be M/D, where D is the ratio of the network difficulty and the difficulty per share. Under steady state conditions, the expected reward for a share is equal to the probability that a block will be found in the next N levels times the reward should a block be found, and will equal (M/D) * (1/M) = 1/D. This means that the expected reward for a share is independent of M as long as the equal-difficulty and steady-state assumptions hold.

And what if they don't hold? Both can bring up a potential problem: a malicious or selfish entity can change their mining behavior in order to flush out or prolong the lifetime of a cohort of shares. If Alice has a burst of good luck, and mines 10 shares out of 20 when she normally should only mine 2 shares out of 20, then she can change her subsequent mining behavior in order to keep that burst of good luck in the last N levels for as long as possible. She can do this either by working on extra-high-difficulty shares or by intentionally mining siblings instead of children on the DAG. On the flipside, when Bob has a spell of bad luck, he can erase it faster by working on low-difficulty shares and trying to always mine DAG children. Note that this vulnerability already exists in p2pool, as individual nodes can specify different share difficulties. The DAG does not create the issue; it's simply an issue with PPLNS with variable difficulty. The issue also does not promote hopping, as hopping only makes sense when the expected reward for a share depends on the past mining results, whereas this issue makes revenue dependent upon the future behavior of other miners.

In any case, it's simple enough to fix. Instead of doing PPLNS where the window is based on the number of shares (or the height in the share DAG), we can do PPLKW (pay-per last K work) where the window is based on an amount of work performed. We set some work threshold (e.g. enough to find 3 blocks on average), then go back through the DAG one level at a time and count all the shares in each level until the total work counted exceeds our work threshold. Thus, each share will always have the same proportion of the total work regardless of future behavior of other miners. The only way to get an enemy's shares out of the DAG faster is to add hashrate and increase the rate at which blocks that reward them are found.

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squidicuz
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June 17, 2016, 12:27:09 AM
 #14595

Good news: The Antminer S9 works fine on p2pool with no modifications. I've been running mine on p2pool for the last 8 hours, and it's producing within 1% of the hashrate that I saw when I tested it on a traditional pool.

Ditto!  Mine are up and running well too.

Everyone, lets update to the latest version from the main repo (version 16).  Nodes are reporting we are around 30% there.
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June 17, 2016, 12:31:16 AM
 #14596

p2pool node scanner has been updated: http://p2pool.co

Please send any more updates and let me know how we can make it better.

I am not seeing any nodes come up on the page... Did you remove the ones you had listed?
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June 17, 2016, 04:15:04 AM
 #14597

I haven't seen any ways in which DAGs could incentivize hopping, as it's still PPLNS and expected reward is independent of the work done since the last block was found.
It is not. With the scheme as described the split factor for block rewards is not constant (ignoring difficulty changes) as it is for PPLNS (i.e. 1/N). More shares at the same height means rewards split more ways, which reduces the expectation for a winning share. This is in some way analogous to PPS, and will uncover similar problems.
To clarify, expected reward for a share is independent of the work done since the last block was found. If there are more shares per DAG level/height, that means that your share will stay in the last N height for a longer amount of time, so it will have a greater probability of being rewarded, but the reward will be smaller.

Let M equal the number of shares in the last N levels of the DAG. The average number of shares per level is M/N. Assume all shares have equal difficulty for now, and assume steady-state conditions, where M stays roughly constant for a single share's transit through the last N levels. Should a block be found, each share's reward will be 1/M. The probability that a block will be found depends on the amount of work done among those M shares.

No it doesn't. The probability that a block will be found on the next attempt (ignoring various constant scaling factors) is 1/D. It is independent of M. As M grows then mining becomes less profitable and it is more profitable to hop elsewhere.

The reason this doesn't happen with PPLNS is that N is constant. M is not.

Sorry, I didn't read the rest of your post because it seemed premised on an error. Once we get past the initial error the rest of the discussion may be worth another look.


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June 17, 2016, 05:53:09 AM
 #14598

No it doesn't. The probability that a block will be found on the next attempt (ignoring various constant scaling factors) is 1/D. It is independent of M.
By "on the next attempt" do you mean on the next share, or on the next level of the DAG, or something else? If you mean on the next share, then you need to multiply by M/N to correct for the expected number of shares per DAG level. According to PPLNS, your share only gets kicked off after a certain number of DAG levels, so you get multiple "attempts" per level.

As M grows then mining becomes less profitable and it is more profitable to hop elsewhere.
If you're referring to the situation where you mine a share, then the number of shares per level changes abruptly, then yes, there will be anomalies in expected revenue. I addressed that issue in the part of my post that you didn't read. It doesn't lead to hopping, though, because it depends on events that happen after a share is found, whereas hopping requires the miner to make decisions based on events that happen before a share is mined.

The reason this doesn't happen with PPLNS is that N is constant. M is not.
It does happen with PPLNS, because the difficulty of the last N shares is not constant. As I mentioned in my earlier post. And it's easy to fix. As I mentioned in my earlier post.

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June 17, 2016, 11:23:27 PM
 #14599

No it doesn't. The probability that a block will be found on the next attempt (ignoring various constant scaling factors) is 1/D. It is independent of M.
By "on the next attempt" do you mean on the next share, or on the next level of the DAG, or something else? If you mean on the next share, then you need to multiply by M/N to correct for the expected number of shares per DAG level. According to PPLNS, your share only gets kicked off after a certain number of DAG levels, so you get multiple "attempts" per level.

Are all shares paid equally, or is this a scoring-based system?

I think if I am reading correctly, all shares are paid equally. That means during periods that M is higher due to random variation, the value of mining on the pool is lower. During periods that M is lower, the value of mining on the pool is higher. The steady-state average is not what matters here because the miner can choose to participate only during certain system states.

If you attempt to apply a score to correct for this, you can do that, but then you have the issue of how to score multiple shares at the same level. To do this fairly and unexploitably, you need an order. Back to square one.
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June 18, 2016, 05:23:45 AM
 #14600

Are all shares paid equally, or is this a scoring-based system?
Shares are paid in proportion to their difficulty. You take the difficulty for a share, divide by the summed difficulty of all shares among the last M (or N for vanilla p2pool), and multiply by the block reward for that block (including fees), and that gives you the reward a share would receive for that block if it were found.

I think if I am reading correctly, all shares are paid equally. That means during periods that M is higher due to random variation, the value of mining on the pool is lower. During periods that M is lower, the value of mining on the pool is higher. The steady-state average is not what matters here because the miner can choose to participate only during certain system states.
In periods where M is higher due to random variation, the probability of a share getting rewarded by another share finding a block increases, but the payout size decreases. These effects cancel out.

For example, if M is 4 (and all shares are the same difficulty), then if I mine a share, it will have 4 chances of probability 1/D to earn 1/4 of a block. If M is 256, then my share will have 256 chances of probability 1/D to earn 1/256th of a block. In either case, the expected revenue is the same.

The problem comes not when M is higher or lower, but when M is rapidly changing.

A share will be payable for a considerable amount of time, and M might change during that time. For example, if N is 4, my share will have its potential reward calculated 4 different times as it travels through different levels of the DAG. Let's say that we start with 1 share per level in all 4 levels of the DAG when my share is mined (my own share being the top level). After this, 1 more level is mined with 1 share per level, and then a level with 5 shares is mined, followed by another two levels with 1 share. The first chance I have to get paid comes from my own share, where the DAG looks like this:

Round 0:
1*
1
1
1

I get one 1/D chance of getting a 1/4-block reward here. (The asterisk denotes my share.) Next round:

Round 1:
1
1*
1
1

1/D chance of getting a 1/4-block reward.

The next round is a bit tricky. Five shares are mined at once, but since they aren't yet aware of their siblings, each one sees the top level of the DAG as having only one share:

Rounds 2a-2e:
1
1
1*
1

Five 1/D chances of getting a 1/4-block reward. Finally:

Round 3:
1
5
1
1*

One 1/D chance of getting a 1/8-block reward.

Total expected reward = 2*(1/4D) + 1*(5/4D) + 1*(1/8D) = 15/8D blocks. The fair reward would be 1/D blocks.

The above was a rather contrived and extreme example. I wrote a script to simulate the rewards for a N=2016 PPLNS system with between 1 and 10 shares per level, and the typical revenue per share varies by less than 1%, with the maximum I've seen being 2.6%.

Again, you can't hop based on this, because it depends on events that happen after you mine a share, which can't be predicted. It's a selfish mining vulnerability, but not a hopping vulnerability.

And also again, this variation is completely eliminated by the PPLKD scheme I described earlier.

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