double check server online - Page 2

ltd · 2009-01-03, 23:01

It has been a very long time since the last update.
I wanted to share with all of you the error rates found within the testrange for k=168451 and n>3M and n<3.95M (with some small gaps)

After cleaning up false positives (That is pairs that are done using clients that give residues that are not comparable) we have the following numbers.

Within 1161 tests we had 6 mismatches without good reason so far. That means that we have an errorrate of only 0.52% for that range!!!!!!!!!

opyrt · 2009-01-04, 00:13

Great news! Thanks for the update! :)

VJS · 2009-01-05, 17:19

LTD,

That is really exceptional news

Almost too good to believe

A recent post in Mersenne in another section showed error rates of 3-5% depending on the n.

Note the following:
- one error any time during the test will create a residue mismatch.
- Mersenne tests are much longer therefore much more suseptable to errors

I still maintain that we should continue with the doublechecking of one k up to the firstpass level.

Major reason is we did find some errors and that error rate should acutally increase with n. Lets not get caught behind the 8-ball when it comes to error testing.

Great news is that from your calculations we do not have to increase the entire secondpass level beyond the 1.5M that its currently at.

I will spend more of my CPU resources on the one k.

Opyrt, and others, Lars sent me a file just a few minutes ago. We will see how much of a dent I can put into the k from 5.5M up. So hopefully once secondpass reaches around 5.5M we will have another large jump.

ltd · 2009-01-05, 22:43

Quote:

I still maintain that we should continue with the doublechecking of one k up to the firstpass level.

Major reason is we did find some errors and that error rate should acutally increase with n. Lets not get caught behind the 8-ball when it comes to error testing.

That is then reason why I stated somewhere else that I am very interested to see the developement of the error rate above 4M and up to first pass. Depending on the real numbers we can then decide how to procede.

Depending on the results I think there will be at least four differnt ways to react:

1. Error rate stays very low: procede with the "one K" solution until the error rate increases
2. "Higher" error rate which has an error pattern. DC all pairs with the same pattern and then fall back to "one k"
3. higher error rate without any signifcant pattern.
I see two ways to react here:
a. Start a complete DC in the region the error rate increased.
b. Start a complete DC for all pairs.

ltd · 2009-02-15, 21:58

Due to the high error rate from 2 user accounts I decided to add all results from these users to the dc queue. We will have an additional set of 260 tests in the range n>3.7M and n<4.15M. The chances that one of these tests contains a prime are minimal but better sure the sorry.

I want to invite everybody with a spare system to help in a short sprint to clear these tests. With an additional 10 Cores running 24/7 we should be able to finish these tests in around 10 days.

VJS · 2009-02-16, 01:43

Lars,

Personally I think its great that you can pick these things out with the DC effort.

opyrt · 2009-02-16, 15:48

Good job Lars! :-)

I see the first of the tests have already been handed out from the server.
Do you inform the users with the invalid tests? I personally would like to know if my computsers were producing garbage @100% CPU 24/7. :-)

ltd · 2009-02-16, 16:30

If the user is still active I send a mail informing about the problem but in this case both users are not active anymore and the results are around a year old. So I decided not to contact them.

About puting resources to DC testing:

My i7 is now up and runing. 4 virtual cores run DC on the llrnet server. The other 4 virtual cores run different projects which use more RAM to see if that is also stable. With this configuration I get 14.x ms per iteration.
When I switch off the additional task to have only the 4 cores work on llr without using the HT I am down to 10ms per iteration. When the real CPU cooler arives I will see if some overclocking is possible.

opyrt · 2009-02-17, 08:37

Will we be granted double check credits for these tests? Even though they are actually triple check? :-)

Not that it's important, I'm just curious.

ltd · 2009-02-17, 09:30

All test in the DC queue give DC credits.

ltd · 2009-02-21, 12:22

News from our extra DC run. No prime so far but it is good that we redue the ranges. Specialy the results from one of the users are worse then I expected. There are between 20-30% errors from this machine!!!!

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2009-01-03, 23:01	#12
ltd Apr 2003 1100000100₂ Posts	It has been a very long time since the last update. I wanted to share with all of you the error rates found within the testrange for k=168451 and n>3M and n<3.95M (with some small gaps) After cleaning up false positives (That is pairs that are done using clients that give residues that are not comparable) we have the following numbers. Within 1161 tests we had 6 mismatches without good reason so far. That means that we have an errorrate of only 0.52% for that range!!!!!!!!!

2009-01-04, 00:13	#13
opyrt Apr 2008 Oslo, Norway 7×31 Posts	Great news! Thanks for the update! :)

2009-01-05, 17:19	#14
VJS Dec 2004 13×23 Posts	LTD, That is really exceptional news Almost too good to believe A recent post in Mersenne in another section showed error rates of 3-5% depending on the n. Note the following: - one error any time during the test will create a residue mismatch. - Mersenne tests are much longer therefore much more suseptable to errors I still maintain that we should continue with the doublechecking of one k up to the firstpass level. Major reason is we did find some errors and that error rate should acutally increase with n. Lets not get caught behind the 8-ball when it comes to error testing. Great news is that from your calculations we do not have to increase the entire secondpass level beyond the 1.5M that its currently at. I will spend more of my CPU resources on the one k. Opyrt, and others, Lars sent me a file just a few minutes ago. We will see how much of a dent I can put into the k from 5.5M up. So hopefully once secondpass reaches around 5.5M we will have another large jump.

2009-02-15, 21:58	#16
ltd Apr 2003 2²·193 Posts	Due to the high error rate from 2 user accounts I decided to add all results from these users to the dc queue. We will have an additional set of 260 tests in the range n>3.7M and n<4.15M. The chances that one of these tests contains a prime are minimal but better sure the sorry. I want to invite everybody with a spare system to help in a short sprint to clear these tests. With an additional 10 Cores running 24/7 we should be able to finish these tests in around 10 days.

2009-02-16, 01:43	#17
VJS Dec 2004 100101011₂ Posts	Lars, Personally I think its great that you can pick these things out with the DC effort.

2009-02-16, 15:48	#18
opyrt Apr 2008 Oslo, Norway 7·31 Posts	Good job Lars! :-) I see the first of the tests have already been handed out from the server. Do you inform the users with the invalid tests? I personally would like to know if my computsers were producing garbage @100% CPU 24/7. :-)

2009-02-16, 16:30	#19
ltd Apr 2003 2²·193 Posts	If the user is still active I send a mail informing about the problem but in this case both users are not active anymore and the results are around a year old. So I decided not to contact them. About puting resources to DC testing: My i7 is now up and runing. 4 virtual cores run DC on the llrnet server. The other 4 virtual cores run different projects which use more RAM to see if that is also stable. With this configuration I get 14.x ms per iteration. When I switch off the additional task to have only the 4 cores work on llr without using the HT I am down to 10ms per iteration. When the real CPU cooler arives I will see if some overclocking is possible.

2009-02-17, 08:37	#20
opyrt Apr 2008 Oslo, Norway 331₈ Posts	Will we be granted double check credits for these tests? Even though they are actually triple check? :-) Not that it's important, I'm just curious.

2009-02-17, 09:30	#21
ltd Apr 2003 772₁₀ Posts	All test in the DC queue give DC credits.

2009-02-21, 12:22	#22
ltd Apr 2003 2²·193 Posts	News from our extra DC run. No prime so far but it is good that we redue the ranges. Specialy the results from one of the users are worse then I expected. There are between 20-30% errors from this machine!!!!