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2018-10-22, 14:28   #309
kriesel

"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest

47×109 Posts

Quote:
 Originally Posted by James Heinrich edit: also note two things about the bounds on mersenne.ca: 1) the P-1 bounds in the GPU72 line are wrong, they are not adjusted as described above, I need to figure out how to do so. 2) the P-1 bounds in general are close to magic numbers, they're currently plucked off an Excel graph I did in 2008 based on observed bounds for exponents 1M-500M, so while they might be reasonably close to reality, they'll never match exactly.
Thanks for the explanation. I had thought that the red font used for negative numbers in the difference row meant that they were considered somehow insufficient.
Similar questions had arisen in regard to CUDAPm1, which would be a little easier to manage worktodo entry adjustment on, since it is all manually assigned and manually reported, rather than sometimes being assigned and completed quicker than I would have time to intervene as on primenet-connected prime95.

I've seen some manual P-1 work done in CUDAPm1 be marked as expired when the result was reported, and that seemed to occur when one or both the bounds reported were lower than the primenet values at mersenne.ca.
A recent example is https://www.mersenne.org/report_expo...0000797&full=1 https://www.mersenne.ca/exponent/200000797
A particularly interesting case is https://www.mersenne.ca/exponent/200000551, where I pushed the manual P-1 to runs saved = 3, and tf and p-1 bounds all exceed primenet values, yet the computed probability fell a bit short.

2018-10-22, 17:33   #310
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

1101001000012 Posts

Quote:
 Originally Posted by James Heinrich 1) the P-1 bounds in the GPU72 line are wrong, they are not adjusted as described above, I need to figure out how to do so.
I transcribed the Prime95 P-1 bound estimator to PHP so I should now be able to get the same numbers are Prime95 (I'm going on the assumption that plenty of RAM is available, as in sufficient to do the whole P-1 in a single pass, for simplicity, so bounds may be slightly higher than what you may get in real life). However the code is quite ponderous due to the (large) number of iterations it goes through to find the "optimal" solution... 66k iterations at 276 and 116k iterations at 271, which has a non-trivial runtime (several seconds) such that I wouldn't want to use it on a live webpage. Now you know why it takes forever to get an estimated completion date if you have many P-1 assignments in Prime95. I'll have to see if I can optimize it somewhat while remaining relatively accurate...

The numbers I got for M89200591:
Code:
TF=71
[b1] => 950000
[b2] => 26600000
[success_rate] => 0.059250926679056

TF=76
[b1] => 725000
[b2] => 14318750
[success_rate] => 0.031280274205779

 2018-10-22, 23:23 #311 irowiki   Sep 2018 4516 Posts So I just realized two of my "higher end" machines (Haswell or so) are 32 bit windows 7 (don't laugh too much, I have some old stuff). Is that going to impact LL/PRP testing or should I redo them into 64 bit? I saw a thread from 12 years ago that said it wouldn't affect it so I thought I'd ask now. Last fiddled with by irowiki on 2018-10-22 at 23:25
2018-10-23, 00:04   #312
James Heinrich

"James Heinrich"
May 2004
ex-Northern Ontario

336110 Posts

Quote:
 Originally Posted by James Heinrich I'll have to see if I can optimize it somewhat while remaining relatively accurate...
Indeed. By picking some more sensible starting, ending and step points in the loops I cut the iterations from 65000 to 1500 and a much more sane runtime while still getting more-or-less the same results.

Looking back at https://www.mersenne.ca/exponent/89200591 the table at the top should now show better values for P-1 on the GPU72 line, and more sensibly show that despite the lower P-1 bounds the overall factor probability was higher due to more TF.
Attached Thumbnails

2018-10-23, 14:35   #313
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

22×1,873 Posts

Quote:
 Originally Posted by irowiki are 32 bit windows 7 ....Is that going to impact LL/PRP testing or should I redo them into 64 bit?
Redo. 10-20% gain

2018-11-13, 16:35   #314
irowiki

Sep 2018

3×23 Posts

Quote:
 Originally Posted by Prime95 Redo. 10-20% gain
Okay, for science I figured I'd post my results here. I redid the machine, and flipped it from Win7 32 bit to Win10 64 bit.

It is an i3-3220 with 4 GB (2x2).

It's doing about 9% better. Score!

 2018-11-20, 18:12 #315 Cruelty     May 2005 23·7·29 Posts Using latest version 29.4.b8 (Win64) on Skylake X platforms, I have noticed that in main thread after launching Prime95 there is: Code: Optimizing for CPU architecture: Corei3/i5/i7, L2 cache size: 256 KB, L3 cache size: 14080 KB Whereas L2 cache should be reported as 1MB In undoc.txt there is a section concerning L2 cache size, but it's said to relate to Pentium 4 architecture: Code: CpuL2CacheSize=128 or 256 or 512 CpuL2CacheLineSize=32 or 64 or 128 CpuL2SetAssociative=4 or 8 After setting it to: Code: CpuL2CacheSize=1024 CpuL2CacheLineSize=64 CpuL2SetAssociative=16 Program reports it properly: Code: Optimizing for CPU architecture: Corei3/i5/i7, L2 cache size: 1 MB, L3 cache size: 14080 KB Question: should detection of L2 cache parameters affect Skylake X performance? After setting it to proper values I haven't noticed improvement in iteration times, at least for FMA3 FFT length of 864K. Another minor issue I have noticed is the representation of CPU information - the line below L1 cache information is unreadable (see attachment) Attached Thumbnails
 2018-11-20, 18:59 #316 kladner     "Kieren" Jul 2011 In My Own Galaxy! 2·3·1,693 Posts Sorry. This is about the latest version. No thread, yet. I switched to 295B4 in the past two days. I just noticed that Manual Communication and Unreserve Exponent menu items are greyed out. I tried commenting the GPU72 proxy out of prime.txt, with no change. Did I do something wrong? I don't think I've ever seen this, before. This persisted after program and system restarts. EDIT: Found the cause. In prime.txt I found 'UsePrimenet=0'. I guess this was a misstep in transferring the prime.txt information to the new version. Changed to '=1' and all is well. Maybe not. On contacting the server, I was told that the assignment key for a 60% done DC (482955xx) 'belongs to another user.' However, this did not remove the assignment from P95. What I see is that GPU72 is still aware of this assignment, but Primenet does not update progress. However, Primenet Exponent Status still lists me as the owner. Last fiddled with by kladner on 2018-11-20 at 20:23
2018-11-20, 19:56   #317
Chuck

May 2011
Orange Park, FL

2·443 Posts

Quote:
 Originally Posted by Cruelty Another minor issue I have noticed is the representation of CPU information - the line below L1 cache information is unreadable (see attachment)
Mine also cuts off the last line; is it because the AVX512F wraps to a new line?

 2018-11-20, 20:11 #318 Prime95 P90 years forever!     Aug 2002 Yeehaw, FL 22·1,873 Posts I will widen the dialog box. The L2 cache mis-detection is a known bug, I do plan to fix it. The bug does not impact performance.
2018-11-20, 23:52   #319
irowiki

Sep 2018

10001012 Posts

Quote:
 Originally Posted by kladner Maybe not. On contacting the server, I was told that the assignment key for a 60% done DC (482955xx) 'belongs to another user.' However, this did not remove the assignment from P95. What I see is that GPU72 is still aware of this assignment, but Primenet does not update progress. However, Primenet Exponent Status still lists me as the owner.
Are you still listed with your ID in File -> Primenet? I've had some of my clients randomly switch to anon and I had to switch it back.

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