20031213, 17:36  #1  
Sep 2003
Borg HQ, Delta Quadrant
2×3^{3}×13 Posts 
Time to change LL vs. TF weight?
From the PrimeNet FAQ:
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20031213, 18:00  #2  
Nov 2003
3×5×11 Posts 
Quote:
1) It is hard to tell what will happen after the runup due to M40. 2) At 25.3M, there is an FFT size cutoff, at which point LL tests will take 20% longer than they do now. Considering the TF leading edge is at 24.1M, and the LL leading edge is at 22.0M, it is safe to assume TF will reach the cutoff before LL catches it. I do agree, however, that something will have to be done before TF reaches 28M, and starts factoring to 2^68. Last fiddled with by nfortino on 20031213 at 18:01 

20031213, 21:24  #3  
Sep 2003
A15_{16} Posts 
Re: Time to change LL vs. TF weight?
Quote:
http://opteron.mersenneforum.org/png/leading_edge.png 

20031213, 23:45  #4  
Sep 2003
Borg HQ, Delta Quadrant
2·3^{3}·13 Posts 
Re: Re: Time to change LL vs. TF weight?
Quote:
a) Assign LLs concurrently with TFs, which defeats the entire purpose of doing trial factoring or b) Assign LLs after the TF completes, which will lead to long delays in LL testing Either alternative is unacceptable in my opinion, which means we need to get more PCs to do TFs. 

20031214, 01:25  #5  
Sep 2003
5025_{8} Posts 
Re: Re: Re: Time to change LL vs. TF weight?
Quote:
I'm pretty sure the server just waits for the TF to complete or expire before assigning that exponent for LL testing. Sometimes that causes long delays, but long delays for a small fraction of exponents are a fact of life on this project  there are more than 1500 exponents under 17M that have not yet been LL tested to completion (or factored). Usually the delay is due to a slow LL test... in a few cases it will be due to a slow TF. The main thing is, computers doing LL testing have a plentiful supply of alreadytrialfactored exponents to work on. Only about 1.5% of the exponents at the current LL leading edge have not yet been trial factored. By contrast, you have to go as far back as 7M below the LL leading edge before the number of outstanding LL tests drops to such a low percentage. Clearly, the main cause of delay for the overwhelming majority of longdelayed exponents is not slow trial factoring, but slow LL testing. 

20031214, 01:44  #6  
Sep 2003
Borg HQ, Delta Quadrant
2·3^{3}·13 Posts 
Re: Re: Re: Re: Time to change LL vs. TF weight?
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In your post you say that you think the server waits for the TF to complete or expire. If we're waiting for TFs to complete or expire we can't be doing LL tests which means a shortage and maybe a nonexistance of firsttime LLs. If we take LLs from beyond the leading edge of TF then we defeat the purpose of TF. I'm not trying to be an alarmist here, but we have to face reality. At this rate LL tests will overtake TFs and then we will have a large problem to deal with. The solution will not be an easy one and it will take time to implement and allow the results to filter through, which is why we should implement it soon to prevent that from happening. 

20031214, 01:50  #7 
Aug 2002
2×3×53 Posts 
I tend to agree that it is time to give TFing more value.
I don't really care about whether the LL tests are catching up or not, if my computer is doing valid work on this project, why shouldn't I get the same credit someone doing an LL or DC test does?????? 
20031214, 02:10  #8 
Sep 2003
29·89 Posts 
Attached is a graph drawn from a recent summary.txt.
I don't agree that 20.1M constitutes the trailing edge of LL testing. The graph doesn't show it. There's a small dip there, but that turns out to be due to a large number of manuallyassigned exponents in that particular 0.1M range: half that range (20.104M to 20.15M) is reserved for manual assignment (but not assigned to anyone). At the current leading edge of LL testing, we're waiting for only about 1.5% of the exponents to complete TF  about 30 out of 2000  which leaves the other 98.5% available for LL testing. That's not a shortage. There won't be a shortage of LL tests unless the leading edge of LL testing catches up to the leading edge of TF. But at current rates of convergence (http://opteron.mersenneforum.org/png/leading_edge.png) that won't happen for many years. Last fiddled with by GP2 on 20031214 at 02:14 
20031214, 02:16  #9 
Sep 2003
29·89 Posts 
For what it's worth, we're already seeing an increase in trialfactoring P90 CPUyears per day, probably due to postM40 new accounts:
http://opteron.mersenneforum.org/png/TFspeed.png By contrast, we haven't yet seen a boost in LL testing rate... in fact, it's actually dipped recently (to below 700 CPUyears / day). 
20031214, 02:24  #10 
Sep 2003
29×89 Posts 
George,
Perhaps the manual range 20104000 to 20150000 (listed as '***** not assigned to anyone!!! ***') should be in fact be released to PrimeNet. Especially considering the relative proximity to M40... if by any tiny chance an "island theory" twin of M40 is hiding in there, it would be nice to flush it out. 
20031214, 02:32  #11  
Nov 2003
3×5×11 Posts 
Quote:


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