Topic: A guide for mining efficiently on P2Pool, includes FUD repellent and FAQ - page 12. (Read 174849 times)

Eligius - It's actually CPPSRB - Capped Pay Per Share with Recent Backpay

I understand the value of p2pool but I don't think that a failing pool is all that costly. If you have a failover you shouldn't have any issues when the primary is down. Worst case is that you'd lose out on anything that wasn't distributed to you yet - hopefully < 0.2

Which fee free PPS pool is that? Are there any left? Mining at a fee-free PPS pool might cost less now, but the risks of the pool failing are high so the cost may be more than you imagine.

This a great guide - thanks!

I have a couple of questions.

This thread, and others, have said:
I'm new to bitcoin (as my rep will tell you), but I understand the concept of luck and variance. How specifically does p2pool "out pay" others? I currently mine on a no-fee (keep trans fees) PPLNS pool. My analysis shows that the trans fees are ~1% so p2pool will out pay there. How else? Is there some sort of reduced latency bonus? Or just a "no-downtime" gain? I read somewhere that >100% efficiencies are "stealing" somehow gaining from others with low pool efficiency by getting their hash power but not always giving credit -- or something.

Also, this guide mentions using: Can you elaborate? the -g sets the miner to a single thread (opposed to 3 on my machine). Isn't that going to reduce my hashrate? the -Q 0 seems inefficient too but I assume that I'm missing something. The --gpu-dyninterval default is 7 but you recommend 50. I don't understand why. These setting seem really important so I really want to understand.

Finally, how is difficultly handled? Hosted pools can auto-adjust this "magically". How can I tell what I should set mine to (or leave it at) and how do I do it?

I'm not sure I understand the question. Why do you need a proxy? Do you have a firewall blocking access to your P2Pool node? P2Pool supports both direct getwork and stratum connexions from miners so you shouldn't need a proxy at all.

Question.. in the OP it didn't mention about setting up a stratum proxy so that miners futher away from your p2pool instance can connect via stratum. How would I do that? I know how to set up a proxy for local getworks TO a stratum receiver, but it's the setting up of a stratum receive to p2pool I don't understand yet.

To be fair, the only bad thing about p2pool is Python language. Which makes it completely useless on low-end PCs.
Hope some day p2pool will be integrated efficiently into bitcoind; reserved my donations for that...

There are 2 problems with your arguments.

• I use "can be obtained" because it involves more than simply using tmpfs. If you have enough RAM, you indeed can obtain the best results. It's left to the system administrator to find out how to tune and monitor a system using tmpfs.
• tmpfs can indeed use swap, but unlike you wrote last time I checked ramfs isn't bounded. So if your RAM isn't large enough to fit your tmpfs system at least you can set a boundary and avoid unpredictable behaviour. If you use ramfs and bitcoind's data directory grows to a point where it fills your whole RAM it will put everything else in swap and eventually trigger the kernel OOM killer. What will be killed then can only be guessed.

So ramfs isn't a clear-cut better solution here: it depends on how the system admin is configuring the whole setup. Anyway this is for advanced admins: people shouldn't follow a guide for this but fully understand the implications themselves. I wouldn't recommend it but I'll add ramfs as an option in the guide.

To check what I just wrote about ramfs:
You can write 30M to a 20M ramfs (at least on a 3.7.9 kernel)...

Edit: man mount clearly shows that there's no options for the ramfs filesystem. So "-o size=20m" isn't even an initial value or a hint, it's completely ignored.

i guess i'll say it again, since it's still on there

the statement:

The best results (but probably by a negligible amount) can be obtained when the bitcoind data directory is on tmpfs

is incorrect.  one can make a tmpfs drive that runs "low" on memory ("low" default being 50%?), in which case it'll start using swap space, slowing bitcoind down

with ramfs you have total control over how much RAM to use on the drive and that's all it'll ever use.  it's not too hard to tell how large you should make a ramfs drive.  at this moment, around 8.5gb

I am a mathematical expert. If your hash rate solves 2 blocks every day over 90 days, there is a 9.4% chance that in any given 90 day period you'll have < 90% "luck"

If your hash rate solves 1 block every day, there is a 19% chance that you will have less than <90% luck in a 90 day window.

So when p2pool's hash rate was low the pool was more likely to have < 90% luck over 3 months than someone throwing a 6 on a 6 sided dice.

My point is that I'm kind of surprised people think something that has between a 1/10 and 1/5 chance of occurring is a sign it is broken.

Oh dear. I come to this thread to read about how to optimise p2Pool. I don't understand the optimisations very well - I just don't have sufficient geek, or a sufficiently stable / low latency network. But it is an interesting read none-the-less.

What aren't interesting reads are the continual claims that something is wrong with the pool, and causing it "bad luck". Here are a few things which anyone should consider when making a "luck" claim one way or the other:

1. Talking about average "luck" over a number of days leads to claims that bad luck periods go for a long time, and good luck for only short periods. This is because when fewer blocks are solved by the pool, the "bad luck" stretches in time. If you instead look at a graph of average luck per block, or better yet the boxplots I posted, you can see that the recent "bad luck" is a small deviation that has actually been shorter than some other deviations. I'll just bold that: Average luck per time period is misleading.

2. This is something Meni Rosenfeld brought up when I was first analysing p2Pool's luck - how could a period of "bad luck" be a problem with the pool? I don't see anyone proposing any mechanisms.

3. The published stats are going to be a little inaccurate. If anonymised earnings per hashrate for a large number of miners could be posted somewhere I think the "luck" discussion would end for all time.

Sorry, I'm not good with names.  No offense intended.  


I wouldn't call it nitpicking.  The fact is under a week ago, 90+ day performance was < 90%.  That is awful in my book.  Is it really luck that suddenly changed this last week?  While I find that hard to believe (and I'm not convinced), I'll defer to the mathematical experts who claim it's all variance and shut up.

M

Scrypt+Stratum fix is in, git users should pull. Others should block stratum by using "--fix-protocol" in cgminer/bfgminer until a new official release comes out.

As always try to keep an eye on new miner and p2pool releases.

I said last week was bad based on the 7 day sliding average data presented on p2pool. I was comparing data from Sunday the 17th (the original date it was posted) GMT to data from the Thursday the 14th GMT. It's semantics and counterproductive to discuss what dates were chosen for the illustration.

What you're nitpicking really doesn't matter at all, this is not a discussion of whether or not we are lucky. I was just illustrating that people confuse "luck" with "it's broken." And I gave an example how over the course of one week we switched from "it's crap" to "it's the best pool in the history of the universe."

The mathematical fact still remains that a well tuned p2pool will out pay any other pool. In fact, it will approach solo mining. If not enough people are mining on it, it will have huge variance. You were unlucky, but someone else who mined p2pool probably had inverse luck. For example, over the past 7 days (March 22), p2pool paid you 185% of what you would have gotten from PPS (including fees). Last week (March 15th), people mining on p2pool were only paid 85% compared to PPS (including fees). Variance (luck) is a problem for all pools that are underpowered and doesn't mean that it "pays out crap."

You keep referring to something I didn't write. I hate that: you are really trying my patience.


The stats page is indeed certainly missing a block which was found during the fork so it's faulty. But even then you didn't say that the luck was "slightly bad" (4.1% below average) but you said "awful". This, by definition, is FUD: you are exaggerating the bad luck which is mostly harmless (4% is within the normal fee range on most pools) to make P2Pool look bad.

And worst of all: you keep coming back on this subject on a thread which doesn't address it and explicitly says so in the first post.

If you pick the worst 90-day window you can find in p2pool's history, you may get a 85% luck. Which doesn't mean much (all pools with low hashrate exhibit high variance) and isn't the subject we don't study low hashrate and its consequences but how to make the most of P2Pool.

I am not asking a question, or spreading FUD.  Simply correcting your erroneous statement of "last week was bad".  The last 90+ days prior to this week were bad, according to the p2pool stats page.  Now if that stats page is faulty, I sit corrected.

M

To be fair, it only very recently hit 95.9%.  For quite some time it was in the upper 80s/low 90s, which is likely what most recent luck posts were using as their basis.  Yes, that's how luck works, and at p2pool's size it's perfectly within expected variance.  Unfortunately, most miners do not like (or understand) bad luck, especially over a long period of time.  Now we're seeing the opposite.  At p2pool's size, it only takes a week of good luck to completely recover from a bad 90-day downtrend.

Which ones? p2pool.info shows 95.9% for 90 days which is already as good as any PPS pool and it doesn't even include yesterday's donation to P2Pool miners from Gavin (for lost income during the fork). "awful" should mean far below standard pools, the numbers don't lie: we aren't far below standard pools. At 98% we are arguably above most of them.


You didn't read the first post or you wouldn't post this kind of question as I explained on what basis I study p2pool's luck.
Even if some weeks are "bad", I never commented on one in particular here.

So your question is bogus and even if it weren't you should already have the answer.

Obviously you aren't here to discuss the subject and instead wish to spread FUD. Please do it elsewhere.

Solely looking at p2pool stats, not gut feeling.  You said a week was bad, on what basis do you make that statement? 

M

The very first post explains that this isn't the place to discuss this unless you have solid data showing that there is a bug somewhere: this thread is for discussions on how to optimize a P2Pool miner's setup not gut feelings.

Over the last 3 months I got 98% PPS with P2Pool. If you call that awful I suppose you can only mine on fee-free pools.

When I track my income over the last 6 months I get ~100.5% PPS.

I really wish people would stop with their gut-feeling and track what their real income is (or at least post such nonsense somewhere else).