Credits : how is it calculated ???

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Profile marsinph
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Message 1902541 - Posted: 23 Nov 2017, 15:18:52 UTC

On the same computer some WU runs faster but receive higher credits than other.
Some runs slower and receive also higher credits !
Also for the same running time there are big difference.
Of course for similar WU (same version) !!!
I not compare WU running on GPU also not compare AP with other

Who can explain ?
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rob smith Special Project $250 donor
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Message 1902543 - Posted: 23 Nov 2017, 15:35:19 UTC

So many folks ask that question......

Crudely, and this is the very simplest way of explaining it:
The time taken by each of the two "valid" wingmen is normalised, and the lower time is used to calculate the credit to be awarded using some (very inaccurate) estimates of the "FLOPS" rate of each of the processors.

(Both the "normalisation" and "FLOPS estimation" processes are prone to significant errors)
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Message 1902544 - Posted: 23 Nov 2017, 15:36:22 UTC

AP are a totally different "breed" of task, but suffer the same issues......
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Message 1902547 - Posted: 23 Nov 2017, 15:44:19 UTC - in response to Message 1902543.  

Tks Rob, but how is is calculated ?
I understand about normalisation
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Message 1902549 - Posted: 23 Nov 2017, 16:14:32 UTC - in response to Message 1902547.  

Tks Rob, but how is is calculated ?
I understand about normalisation

Look here, and cry: http://boinc.berkeley.edu/trac/wiki/CreditNew
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Message 1902550 - Posted: 23 Nov 2017, 16:20:28 UTC

Once the data has been normalised it is translated from the time domain into FLOPS, then scaled to give the awarded credits.
Both wingmen get the same amount of credit for a given task. The driver is the CPU time, with scaling to take into account the differences between processors.
There are various bounds checks along the way to make sure that the end product is "within reason", and various so called "damping factors" are applied to try to reduce the effects of changes in processor and applications. Only the bounds checking works properly most of the time, the damping factors are not correct, and are gradually forcing the awarded credit towards zero (the timecale for which is years)
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Message 1902572 - Posted: 23 Nov 2017, 19:44:53 UTC

Oh just tell him the truth.

It's just a random number generator that just gradually generates lower numbers. ;-)

Cheers.
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Message 1902579 - Posted: 23 Nov 2017, 20:09:07 UTC - in response to Message 1902572.  

Oh just tell him the truth.

It's just a random number generator that just gradually generates lower numbers. ;-)

Cheers.

That´s why we called Credit Screw in the real world. LOL
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Message 1902585 - Posted: 23 Nov 2017, 20:16:48 UTC

A one word explanation of how it's calculated:
Badly
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Message 1902618 - Posted: 23 Nov 2017, 23:31:14 UTC

The more we are supposed to know, the better we also should be able to explain it.
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Message 1902640 - Posted: 24 Nov 2017, 4:53:17 UTC - in response to Message 1902585.  

A one word explanation of how it's calculated:
Badly

+1
Seti@Home classic workunits:20,676 CPU time:74,226 hours
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Profile Chris S Crowdfunding Project Donor*Special Project $75 donor
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Message 1902676 - Posted: 24 Nov 2017, 10:03:20 UTC

The whole shebang can be explained in a few simple words.

    Seti is a 6 day a week project.
    The credit awarded is totally screwed up.
    There is no money in the pot to do anything about it.


Right from the first days of Classic, this Seti@home project was always seen as esoteric in basically looking for little green men. Whilst it is nice to get some credit to see yourself climbing up the leader boards, It is nothing less than ego massaging to be 100% honest. Some kind people are working for free to make things better, but the tide is against them.

People like me support this project because we believe in the basic premise of what it is all about i.e.if we don't look we won't find. But you need a strong constitution to stick with it :-))

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Message 1902683 - Posted: 24 Nov 2017, 11:00:02 UTC - in response to Message 1902676.  

The credit awarded is totally screwed up.
True. But the credit calculations are made by, and the responsibility of, BOINC. SETI is one of the few projects which reveals the true problems with the raw BOINC credit system.

You should direct your comments about resourcing to BOINC, not SETI.
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Profile Chris S Crowdfunding Project Donor*Special Project $75 donor
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Message 1902697 - Posted: 24 Nov 2017, 12:43:44 UTC - in response to Message 1902683.  

1. Fair enough point Richard, and I will do so.

2. Which is why after 17 years I still crunch for Seti.

3. Look on the bright side, you have advance knowledge in your other role :-))
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Richard Haselgrove Project Donor
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Message 1902700 - Posted: 24 Nov 2017, 13:51:27 UTC - in response to Message 1902697.  

3. Look on the bright side, you have advance knowledge in your other role :-))
Indeed. I am still the only person to have commented on BOINC Server issue #2132 - and nobody has done any work on it since I captured those graphs in 2014.
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Message 1902702 - Posted: 24 Nov 2017, 14:12:34 UTC
Last modified: 24 Nov 2017, 14:12:49 UTC

I remember that and even participate on some of the tests and the conclusion was clear, Credit Screw is screwed.

Maybe that explain why other projects like E@H not use Credit Screw.

But as allways, the worst blind is the one who not want to see.
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Profile Chris S Crowdfunding Project Donor*Special Project $75 donor
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Message 1902726 - Posted: 24 Nov 2017, 17:56:45 UTC

We do have Richard on our side and long term posters such as he and I that are not giving up. But it is galling when Eric says that we need more computing power, and it is likely that if we sorted out this credit business we could get it!!
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Message 1902769 - Posted: 24 Nov 2017, 21:18:45 UTC - in response to Message 1902726.  

We do have Richard on our side and long term posters such as he and I that are not giving up. But it is galling when Eric says that we need more computing power, and it is likely that if we sorted out this credit business we could get it!!


Yep, crunch 8 minutes here and receive, maybe 100 points. Crunch another project 8 minutes and receive 1000, 10000, or 20000.

Hmmmmmmmmmmmmm............

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Grant (SSSF)
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Message 1902772 - Posted: 24 Nov 2017, 21:36:01 UTC - in response to Message 1902769.  

Yep, crunch 8 minutes here and receive, maybe 100 points. Crunch another project 8 minutes and receive 1000, 10000, or 20000.

Or 100,000.
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Message 1902774 - Posted: 24 Nov 2017, 21:41:09 UTC
Last modified: 24 Nov 2017, 21:59:15 UTC

The worst side of credit screw is (ussing arkayn example)

If you crunch for 8 min one type of WU you receive 100 credits (hypoteticaly)

Next you crunch the same 8 min, on the same host a similar WU (with the same AR and type) and you could receive 50, 60, 80, or wath else the random credits generator gives.

So it´s not just the low credit paid compared with other projects (with that i could easely live) , is the incapacity to paid the same amount of credit for the same crunching time on the same type of WU on the same host.

Now if you compare the credit paid Arecibo vs blc vs AP then its a total mess. Just watch, almost everyone like to receive a lot of AP WU, since they paid a lot more credit per crunching time against the others, on the same host.

As somebody allways say, credits mean nothing, you can´t exchange credits for nothing (not even the Seti Toaster) and science is done anyway (and that is true), but us homans like to compare our work done and the only way to measure that is with the credit production of the host.

I belive very few knows where or how to discover the daily WU production (by WU type, AR, etc) on a determinate host//users, to make a real comparison. At least i don´t know an easy way.

My 0.02Cents
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Message boards : Number crunching : Credits : how is it calculated ???


 
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