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Old 2008-12-07, 02:27   #1
Prime95
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Default P-1 factoring anyone?

I'll be watching over the next few months how many people sign up for P-1 factoring. We have tons of people doing LL and TF, we need more people signing up for P-1.

In the new scheme of things, if P-1 doesn't get done then when an exponent is assigned to an LL tester he must do the P-1, last 2 levels of TF, and then the LL test.

If not enough people sign up for P-1, I'll have to tweak "do what makes the most sense" to assign some P-1 factoring. We have plenty of time to work this out as the leading edge of exponents that need P-1 factoring and are holding up TF is above 48 million. It will take a while before the leading edge of LL gets that high.
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Old 2008-12-07, 03:11   #2
petrw1
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Why?
Quote:
... last 2 levels of TF ...
Doesn't that happen anymore through your standard TF assignments?

The summary also shows almost 34,000 P-1 available from 44-45M??

What is the preferred hardware for P-1? I have my new Q9550, 64 Bit, 4GB RAM. So it would certainly be a fast factoring maching but then it would also be near the upper end in LL performance too.
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Old 2008-12-07, 05:50   #3
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i'll take it up, once i find out the cause of prime95 not assigning p-1 work to one of my workers
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Old 2008-12-07, 10:20   #4
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I would like to have the 64 bits version of Prime95 25.8.2 (or later) first. Otherwise I will be wasting 6 GB of RAM. I seem to insist on overworking you in my many communications on different channels ;-)

Jacob
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Old 2008-12-07, 13:24   #5
Prime95
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Quote:
Originally Posted by petrw1 View Post
Why? Doesn't that happen anymore through your standard TF assignments?

The summary also shows almost 34,000 P-1 available from 44-45M??

What is the preferred hardware for P-1? I have my new Q9550, 64 Bit, 4GB RAM. So it would certainly be a fast factoring maching but then it would also be near the upper end in LL performance too.
An example: Take an exponent near 51 million. It needs to be factored to 2^69. Tf assignments will take it to 2^67. Then the server wants to assign it to P-1.

If we have plenty of P-1 volunteers, then the P-1 assignment happens in a timely manner, and the exponent is assigned for the final two bits of trial factoring.

If we don't have many P-1 volunteers, when the leading edge of LL testers reaches 51 million the exponent is assigned for LL testing. The LL tester must do the P-1, 2 levels of TF, and then the LL test.

I'm intentionally assigning P-1 exponents that are holding up TF. The 34,000 exponents in 44-45M were TFed by the v4 server which did not stop 2 bit levels shy of completing TF.

Because of memory bandwidth limitations, consensus seems to be a Q9550 should be doing 3 workers of LL/P-1 and 1 worker of TF. If you had one of your 3 LL/P-1 workers dedicated entirely to P-1 then you would be doing more than your fair share.
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Old 2008-12-07, 18:59   #6
petrw1
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Quote:
Originally Posted by Prime95 View Post
Because of memory bandwidth limitations, consensus seems to be a Q9550 should be doing 3 workers of LL/P-1 and 1 worker of TF. If you had one of your 3 LL/P-1 workers dedicated entirely to P-1 then you would be doing more than your fair share.
As S485122 suggested do I not need the 64 Bit Version of Prime95 to go along with my 64 Bit Vista to get the P-1 thruput benefit?
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Old 2008-12-07, 19:27   #7
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Out of curiosity, are you trial factoring residue classes that are more likely to be P-1-smooth to lower bound than the rest?

Alex
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Old 2008-12-07, 20:34   #8
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Quote:
Originally Posted by petrw1 View Post
As S485122 suggested do I not need the 64 Bit Version of Prime95 to go along with my 64 Bit Vista to get the P-1 thruput benefit?
No, but you will not be able to use a lot of memory, which can be a plus since you would still have about 2GB free for other usage...

Jacob
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Old 2008-12-07, 22:20   #9
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Quote:
Originally Posted by petrw1 View Post
As S485122 suggested do I not need the 64 Bit Version of Prime95 to go along with my 64 Bit Vista to get the P-1 thruput benefit?
There are diminishing returns for extra memory. I suspect anything over 500MB yields very small benefits - but I do not have any benchmarks to back that up.
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Old 2008-12-07, 22:20   #10
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Quote:
Originally Posted by akruppa View Post
Out of curiosity, are you trial factoring residue classes that are more likely to be P-1-smooth to lower bound than the rest?
I did not get around to that bit of fine-tuning.
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Old 2008-12-07, 22:22   #11
petrw1
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Quote:
Originally Posted by Prime95 View Post
There are diminishing returns for extra memory. I suspect anything over 500MB yields very small benefits - but I do not have any benchmarks to back that up.
Okay...but isn't it documented that 64Bit OS along with 64Bit Prime95 are faster for factoring? Or is that just for TF and not for P-1?
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