High share difficulty in p2pool for slower miners

hu398

New Member
May 13, 2014
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I've noticed that for some miners in p2pools the share difficultly is much higher than the minimum pool difficulty.

For example currently in p2pool.darkcointalk.org:7903 most of the miners have a share difficulty of 7.697 which is the minimum pool difficulty, but a small number the slower miners have a share difficulty of 21.636 and don't seem to be managing to get enough shares for a payout.

I've searched for answers to this, but haven't managed to find an explanation.

Can any knowledgeable person explain why these miners are not working the pool minimum share difficulty?
 

Propulsion

The buck stops here.
Feb 26, 2014
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XerHCGryyfZttUc6mnuRY3FNJzU1Jm9u5L
I believe they aren't connecting with stratum+tcp:// instead there doing it directly with http://
At least, that's my theory. chaeplin would definitely be the one to know for sure.
For really slow miners, you can always add a custom diff setting like so : -u [address]+0.001 -p 123
 
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hu398

New Member
May 13, 2014
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Thanks for the ideas. I checked the settings on one of my slow miners and it is definitely using stratum+tcp://
Also tried [address]+0.001 but it still got assigned a share difficulty of 26.067
Looking at the various speeds in the pool it seems that all miners <1mh are assigned a high difficulty, anything over 1mh is assigned the pool minimum with the exception of one 133mh miner which also has a high difficulty.
I'll take a look at the p2pool source code and see how share difficulty is being assigned, one thought is that speeds in kilo-hashes are being treated as mega-hash speeds and assigned a suitably high difficulty (so my 270kh miner is seen as a 270gh miner which would be why it has the same share difficulty as the 133mh miner in the pool). Might be able to test this by throttling one of my 2mh miners below 1mh and seeing if the difficulty goes up.
 

Cartman

New Member
May 29, 2014
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You can set your own difficulty by appending a /# after your address.
address/<number>
address/0 will give you the lowest possible diff.

I would shoot for time to share of about 30 minutes. Setting it too low will make your payouts smaller and may cost you when you send coins in tx fee's so be careful.
If you are okay with higher variance let it set itself.

See here for more info: http://xpool.net/faq.html

The address+# is just for setting the pseudo share diff. Mostly useless.
 
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vertoe

Three of Nine
Mar 28, 2014
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The address+# is just for setting the pseudo share diff. Mostly useless.
Pseudoshare diff is not useless on huge nodes. If the pseudoshare diff by the node is very high, you will submit too few shares and recieve much lower payouts. I observed such a behaviour on one of my DOGE nodes.
 

Cartman

New Member
May 29, 2014
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Pseudo shares have nothing to do with payout or the number of real shares you submit. They are only there to keep your miner busy waiting for a real share. I suppose if it is really high your miner may be delayed when it gets a real share. I stand by my mostly useless comment :)
 

vertoe

Three of Nine
Mar 28, 2014
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Pseudo shares have nothing to do with payout or the number of real shares you submit. They are only there to keep your miner busy waiting for a real share. I suppose if it is really high your miner may be delayed when it gets a real share. I stand by my mostly useless comment :)
I dont want to disagree with you. You said "mostly" and that is correct because the case I described is rare.
If the p2pool nodes pseudo share diff is significantly higher than the share diff which is required to get paid, your miner will not submit shares which you would get paid for if they are inbetween this range.
That said, in 9 months p2pool mining I only saw that once.
 

plambe

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May 23, 2014
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I think nvidia GPUs give around 3 times the difficulty. I don't know why, but when I tried mining on my laptop's GPU it showed what you described.