Butterfly Labs - Bitforce Single and Mini Rig Box

[DeathAndTaxes]

Maybe I am wrong, but isn't it always a good idea to return work as it is found even if you are not mining on p2pool? This way if a long poll happens in the middle of the BFL single processing work it could have already returned proper hashes for submission to the pool?

Yes theoretically it would be optimal to always return work as soon as it is found.  Still for efficiency IIRC even GPUs  run an entire "batch" and return all work at the end.  The batch just happens to be small.  Technically the larger batch size may be resulting in slightly higher lost work even in a "normal pool".  5 sec vs 600 sec means the amount lost is much smaller (~1%) and it is likely double that on pools which use merged mining (due to shorter average LP interval).  The very short LP interval of p2pool (10 s) just makes it much more noticeable. 

A smaller batch size should in theory improve efficiency even when used on a normal pool.  On the other hand if the BFL can return results immediately (or store them and make them available for polling immediately) then no batching is necessary.  It could simply process an entire nonce range returning or storing results as needed.  Not sure if that is possible based on the BFL board design though.  If it isn't working in a batch is still a good "workaround".  It is how GPU handle the issue of share latency and they do it pretty well.

There is no "free" lunch when working with a smaller nonce range though.  There is some latency and overhead in setting up work for the processor.  This can be seen on GPU with different intensities.  A 5970 w/ intensity 9 (2^24 hash batch size) is roughly optimal.  Lower intensity means less share latency but most wasted time setting up batches.  A higher intensity means less time setting up batches but longer share latency.

There likely is a similar optimal value for BFL Single. 

[1714114449]

1714114449

[1714114449]

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[jamesg]

I'll just leave these here. 

[DiabloD3]

I'll just leave these here. 

>lower rack
>empty

WHAT SICK MAN SENDS BABIES TO FIGHT ME

*om nom nom*

[jamesg]

>lower rack
>empty

WHAT SICK MAN SENDS BABIES TO FIGHT ME

*om nom nom*

It's cold on that lower rack. Best place for the most highest hashers with lowest power draw to be.

[kano]

The work over-write resolves the issue of working on something that has expired - which is roughly the same on both BFL and Icarus.

The Icarus does something that would seem bad but effectively resolves the problem of throwing away work:
It returns the first nonce that is found, when it is found, and then aborts the job.

What this means in reality is that on average the miner would process half of each nonce range (when it finds a nonce) and then go to the next one
Of course due to random probability that is not an issue, you don't gain or lose anything from processing on average half of each nonce range.
The pool however is required to supply twice as much work, of course (and the miner has the overhead to setup twice as many jobs - which may be negligible)
Also, in cgminer, you need to increase your queue size (I set it to 4) so that when there is a run of low nonce values, you don't run out of work easily.

The optimal solution of any FPGA would be 3 things:
1) allow processing of nonce ranges
2) return nonce's as soon as they are found
3) return a completion message at the end of processing the nonce range

I don't know if it is possible to return early and continue processing with an FPGA - but I would be surprised if it wasn't possible.
GPU's don't have 2) and with a GPU 1) is how intensity works in cgminer
All devices should have 3) but oddly Icarus doesn't so we work around it (and the work around resolves it)

There are different ways the different FPGA's implements this.

Item 2) (the only one that Icarus has) allows working around missing any other items - Icarus is missing both 1) and 3)

BFL only has 3) so the more LP's you get the larger the amount of wasted work (and since P2Pool has 10 seconds LP's ... well that's why I say DONT mine P2Pool with BFL)
The work wasted is (as mentioned before) the processing done that isn't reported when you abort a job.

Item 2) also means you have a better chance of getting your work to the pool in time since it means your miner knows about the results earlier.

Aside: since P2Pool is normally your own pool running, having extra work requests should not be an issue.

[DiabloD3]

The work over-write resolves the issue of working on something that has expired - which is roughly the same on both BFL and Icarus.

Has to be done atomically, I think it can't be easily on here.

[hashking]

>lower rack
>empty

WHAT SICK MAN SENDS BABIES TO FIGHT ME

*om nom nom*

It's cold on that lower rack. Best place for the most highest hashers with lowest power draw to be.

Where can I get some real ones like you did. 

[simonk83]

Where can I get some real ones like you did. 

http://www.butterflylabs.com/

[hashking]

Lol as far as I know they arent sending out any!

[kano]

...
Where can I get some real ones like you did. 

Here: https://bitcointalk.org/index.php?topic=67937.msg801063#msg801063

[jamesg]

Lol as far as I know they arent sending out any!

You guys are kind of ridiculous. I know a guy with a 30Gh mining farm who doesn't have an account on the forums.

Why do you assume that if 100 people don't all post at once that no one is getting singles?

[heavyb]

can you use pocblm gui with the singles?

[jamesg]

can you use pocblm gui with the singles?

No. cgminer or ufasoft.

I would recommend cgminer.

[P_Shep]

Thinking of ordering a couple more... 

[RoloTonyBrownTown]

Lol as far as I know they arent sending out any!

Then you're wrong. My second box is currently in transit.

[stevegee58]

These FPGA boxes are cool, but has anyone here considered the impact to their mining business when the mining reward is cut in half?  That's happening later this year at current mining rates.  At that point if you're currently making say 1 BTC/day, you'd suddenly be making 0.5 BTC/day for the same hash rate.

See https://bitcointalk.org/index.php?topic=67387.0

[DeathAndTaxes]

These FPGA boxes are cool, but has anyone here considered the impact to their mining business when the mining reward is cut in half?  That's happening later this year at current mining rates.  At that point if you're currently making say 1 BTC/day, you'd suddenly be making 0.5 BTC/day for the same hash rate.

See https://bitcointalk.org/index.php?topic=67387.0

Nope.  WTF the reward is going to be cut in half?  Why didn't anyone tell me.

[jamesg]

These FPGA boxes are cool, but has anyone here considered the impact to their mining business when the mining reward is cut in half?  That's happening later this year at current mining rates.  At that point if you're currently making say 1 BTC/day, you'd suddenly be making 0.5 BTC/day for the same hash rate.

See https://bitcointalk.org/index.php?topic=67387.0

Hmmmm. Maybe you should think some more about this before posting.

I could be wrong, but the WHOLE POINT of more efficient miners is to be able to make money when events like the halving of the subsidy happen.

Just a thought though.

[P_Shep]

Careful Giga, some people don't like people 'thinking' or having 'thoughts'.

Damned thinkers, think they think things. 

[kano]

These FPGA boxes are cool, but has anyone here considered the impact to their mining business when the mining reward is cut in half?  That's happening later this year at current mining rates.  At that point if you're currently making say 1 BTC/day, you'd suddenly be making 0.5 BTC/day for the same hash rate.

See https://bitcointalk.org/index.php?topic=67387.0

Nope.  WTF the reward is going to be cut in half?  Why didn't anyone tell me.

... every 4 years
(every 210,000 blocks)
Though I presume your reply was not meant to be taken seriously?