20210701, 09:24  #1 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2×3^{2}×19^{2} Posts 
Production (wavefront) P1
Could we get some more volunteers performing wavefront P1 to good bounds?
The P1 crowd are not keeping up with demand, so the P1 wavefront is essentially the low end of the PRP wavefront, with PRP testers doing a lot of P1 too. Sometimes to good bounds, sometimes not. The work distribution map https://www.mersenne.org/primenet/ shows 687 assignments currently in 104M105M ATM. 175 (25.5%) of those are mine; so 512 others'. A little more help with P1 please? 
20210701, 09:49  #2 
Romulan Interpreter
"name field"
Jun 2011
Thailand
23353_{8} Posts 
The number of assignments is not important. Important is how fast you go through them. You may have a hundred assignments and turn up one every hour, or you may have 5 and turn up one every 20 minutes.
Anyhow, nitpicking apart, that's a good call and I may join you after I finish the current task (12 days more to go), but keep in mind that a lot of P1 work does not appear reserved as so, due to the fact that new flavors of the new programs do the PRP and P1 in the same time. So there may be more activity going on there than it is visible from the reservation chart. Edit: also, low category work is not easy to get, I tried and got 106M, 107M, and 110M. Maybe we can corrupt Chris to offer P1 work for our Colab workers? Last fiddled with by LaurV on 20210701 at 10:07 
20210701, 15:12  #3 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2×3^{2}×19^{2} Posts 
My prime95 P1 workers report results immediately by PrimeNet API, and have a variety of processing speeds; some 5 hours, some 14 hours, etc for ~104M, good bounds P1 & liberal but reasonable for system response ram settings.
Radeon VIIs and other manual assignments get reported usually daily. An RVII can churn through ~40/day each. So yes, there are large disparities in speed. Number of assignments was the measure available. Here's an example of how quickly a completed P1 gets gobbled up. 104614871 Waited over 3 months for P1, then through PRP assignment and completion and in CERT in 2 days. P1 of higher Cat #s is helpful too; prevents them from getting to 1 or 0 without P1 done, so pays off a little later. Last fiddled with by kriesel on 20210701 at 15:37 Reason: edit long url to [M] form / test links always / don't post exponents before breakfast? 
20210701, 21:43  #5 
"Jacob"
Sep 2006
Brussels, Belgium
2^{3}×227 Posts 
If the current software, I’m too lazy now to check, does P+1 at the same time, P1 as a work type is only useful if the exponent gets picked up by an instance that still uses LL and not PRP.
A solution could be to reserve the ”P1’ed” exponents for the LL work requests. Perhaps P1 would be more beneficial on the exponents needing a double check, although the fact that only one LL test would be saved implies lowish bounds, the factoring buffs would redo the factoring attempt with higher bounds. From the time P1 has been available as an independant work type, the bounds should have computed differently for that work type. For P1 as an independent work type the bounds should be based on the mean of Primenet cpu’s and available only to workers with sufficient memory. At the moment they are based on the individual machine doing the factoring attempt, as if it must be the case when an LL test is started on an exponent for which no prior P1 had been done. Jacob 
20210701, 22:42  #6 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2×3^{2}×19^{2} Posts 
LL has been retired as a first time primality test, in favor of the PRP/GEC/proof/Cert sequence, saving about 1.02 times a full DC run.
And there's a case for PRP/GEC/proof/CERT being superior, in DC situations, too, even on past LL first test cases; about equally fast overall run, with far lower error rate. (Almost no PRP DC/TC or quad check runs, compared to 2%4% LLTC cost on average. That's a ~3% speedup, for ~0.4% or less proof/CERT cost depending on proof power.) PRP and P1 may be performed in combination at reduced P1 stage 1 cost, on gpuowl v7.xy, requiring a GPU with sufficient DP performance to be worthwhile, and a sufficient level of OpenCL support in its driver (at least OpenCL 2.0 atomics). Factoring runs intended as P+1 are separate and have a low yield for factors, so not advisable as preparation before PRP or LL first tests or DCs. Also in some cases P+1 attempts turn out to effectively have been P1. Since there may be some running mprime or prime95 or Mlucas versions not supporting PRP proof generation yet, the twoprimalitytest bounds target values are still in place. (PRP without proof generation and subsequently verified Certs would get PRP DC, often with proof generation & cert.) Everyone, please finish upgrading to PRP proof capable software where practical, to help avoid the full cost of a DC. Compared to running 2testsbounds P1 for a subset of exponents that would be destined for LL, LLDC, LLTC, LLQC etc as needed, and 1testsbounds P1 for a subset that would require PRP/GEC/proof assignment, running 2testsbounds P1 on everything is slightly deeper than optimal, but that additional factoring effort can be considered a gift to the factorhunters that will eventually follow. It does yield factors at a satisfying rate. I recently ran 31 100Mdigit exponents that had had TF only to 76 not recommended 81 bit depth. Three of the 31 were eliminated with 4 factors found with P1 bounds (mersenne.ca GPU72 row), only one factor of which would have been found by TF first to 81 bits. No additional factors were found by TF to 81 bits, on the 28 P1 nofactor survivors. A practical consideration is if the P1 bounds run are inadequate, it does not retire the P1 task in the mersenne.org database. Running gpu72 row bounds P1 ahead of all PRP testers ensures that following CPU or GPU PRP assignments will have had sufficient P1 applied to clear the P1 task in the database first, and give the later PRP tester just PRP to do, not P1 first (if sufficient memory is present and enabled on that atP1timeunknown PRP tester, then nofactorfound exponents get PRP). That practical consideration is the case for which this thread was created. It's not the best choice of hardware and software, but it is possible to run suitable P1 bounds for the current wavefront and somewhat higher, on CUDAPm1, on even ancient 1GB NVIDIA GPUs, by bumping the trailing testssaved number in the assignment from 2 to 3. Or by specifying bounds and exponent on the command line. Recommended sequence for wavefront testing is: TF to recommended levels. (Since almost all TF is done on GPUs, to the GPU72 TF level.) P1 to recommended bounds. (Conservative position is to P1 to the larger bounds of PrimeNet or GPU72 rows.) PRP/GEC/proof and Cert. No P+1, no ECM, no LL. (George has confirmed that P+1 factoring is not worthwhile at p~104M, and retired LL assignments.) Except LL the heck out of anything that returns PRP result "probably prime" with a successful Cert, while maintaining confidentiality of the new likely prime discovery. Until the press release is out. Last fiddled with by kriesel on 20210701 at 23:04 
20210701, 22:54  #7 
Jul 2003
Behind BB
31·61 Posts 
Some potential P1'ers might like to know what B1/B2 values are considered "good bounds" for production (wavefront) P1. Could you provide some rough estimates here?
Maybe another way to ask my question: What should x be in the sentence, "Below B1 = x, you are wasting our time (someone will likely have to redo it soon) by doing independent P1 on a wavefront exponent." Last fiddled with by masser on 20210701 at 22:57 
20210701, 23:28  #8 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2×3^{2}×19^{2} Posts 
Typically now recommended bounds are ~B1=650,000,B2=24,000,000. I'm not sure at what exponent that changes again. But anyone can check at https://www.mersenne.ca/exponent/exponent goes here, drop everything else after the last preceding /, that is, everything in bold
For example, https://www.mersenne.ca/exponent/104500391 Prime95/mprime performs an optimization computation at P1 "PFactor" assignment start, and I trust George to have gotten it right, or right enough, providing the system has adequate ram present, and enough ram has been enabled in prime95/mprime by the user. Start with prime95's readme file "desirable" guidance and the system specs. I would use the GPU72 row, not the PrimeNet row, and definitely not the actual row,currently B1=B2=935,000 in the example exponent above, which was a waste of time (B2=B1) and lesser factor probability, only partly compensated by one additional bit of perhapsexcessive TF, on that example exponent. (If it was on an extremely high TF/DP ratio GPU such as RTX20xx or RTX30xx or GTX16xx, it may have been justifiable TF.) See also https://www.mersenneforum.org/showpo...9&postcount=20 which applies generally to prime hunting P1, and has been available since November 2019; IIRC both RDS and R. Gerbicz were in agreement with the conclusions. Things that people sometimes claim are optimal are not. For P1 factoring for prime hunting, do the whole job, well enough, once per exponent. Do not run stage1only. Do not run inadequate bounds. Getting the exact optimal bounds is not critical. As long as the P1 task gets cleared, in the nofactor outcome, the slopes (partial derivatives vs. B1, or B2) of probable computation time near a local or global minimum will be small. I used to do gpuowl default B1=1M, B2=30M for lower exponents. But I can get through P1 of ~35% more exponents per day on the same GPU following the mersenne.ca guidance. Last fiddled with by kriesel on 20210701 at 23:36 
20210701, 23:44  #9 
"Jacob"
Sep 2006
Brussels, Belgium
2^{3}×227 Posts 
I made a mistake : what I remember having read is that there was a possibility of doing stage 1 P1 factoring concurrently with the PRP test and at a much lower cost than doing them separately. The latest readme file doesn't mention this and I couldn't find a relevant posts anymore, not in Ken's reference thread, not via a forum or Internet search. Since I can't find basis of my arguing about P1 bounds my message becomes a bit irrelevant.
In other words I should have done what I admonished others to do : not be lazy and research first before posting. Sorry about that :( Jacob 
20210702, 00:29  #10 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
1962_{16} Posts 

20210702, 01:59  #11  
Romulan Interpreter
"name field"
Jun 2011
Thailand
26EB_{16} Posts 
Quote:
@kriesel: man, please try to keep your posts shorter. If you really feel compelled to write, then write full post, read it again, and delete about half of it, the half you think is less important than the other half. Don't take it personal, some of your posts are really REALLY good, like post #6 above, which is a , but they are TOO LONG. People do not have the patience to read them. And yeah, I know I am the wrong person to give such advice, being myself a long speech guy, and talking rubbish most of the time , but trust me here. (this is personal opinion, I (as a mod) didn't get any complaint recently about the size or content of your posts, but I have to mobilize myself all the time to go through the whole content of some of your posts  and I am a patient reader, I like to read, and I understand the involved math). For post #6, the only addition I would make, in red below, as the exponents get higher, the following algorithm becomes more efficient: Quote:
That is because as the exponents go higher (PRP takes longer) and as most of new cards can do some FFT work (i.e. P1) , then doing P1 will find factors faster than doing the last TF bitlevel. Well.. now there is a long discussion about the fact that P1 gets combined with PRP, which would mean that you have to stop your PRP test after the P1 is done, do the last TF bit, and then continue the PRP. This is freaking inconvenient, and almost nobody is doing it, but it is still the most profitable way. The "intensive_done_P1" exponents should only be PRPed with nonguOWL software, as gpuOwl will do its own P1 at "saved cost". But at the end, everybody should do whatever run their boat... Last fiddled with by LaurV on 20210702 at 02:20 

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