Prime95 v30.4/30.5/30.6

[Uncwilly]

Only if you are near the work that everyone else is doing or you keep less than a day of work in you queue do you need to force coms right away. If you just stick the work in the worktodo.add and go to sleep for the night, at some point it will do coms and pick up the AID. Same thing the other way. Normal coms will catch it.

[drkirkby]

Originally Posted by Uncwilly

Only if you are near the work that everyone else is doing or you keep less than a day of work in you queue do you need to force coms right away. If you just stick the work in the worktodo.add and go to sleep for the night, at some point it will do coms and pick up the AID. Same thing the other way. Normal coms will catch it.

Thank you. I forced the communications because I wanted to verify it all behaved as I was hoping it would, but I take your point, in normal circumstances there would be no need to do it. (For the test purposes I picked an exponent in the 200 million range, so there would have been little interest by others.)

[Zhangrc]

Originally Posted by Prime95

I'll work on improving error recovery in 30.7

Hope you could fix in v30.7 the old "worker windows" bug, where the "CPU cores to use" option is very difficult to adjust.

[kriesel]

Tested on prime95 V30.6b4, dual 12-core Xeon E5-2697v2, Win10 pro, 128 GiB system, total available ram for stage 2 110 GiB, no per worker settings. In local.txt (yes that global memory line could be simplified)

Memory=112640 during 7:30-23:30 else 112640

[Worker #1]

[Worker #2]

For 105M P-1 on worker 1 of 2, 100Mdigit P-1 on worker 2 of 2, while worker 1 stage 1 or 2 coincide with worker 2 stage 1, no ram contention. When worker 2 runs the 100Mdigit stage 2 which will be ~(332/105)^2.1 ~11 times as long as for worker 1's 105M stage 2's, the system will toggle repeatedly several times per 100Mdigit on worker two, between 1 and 2 workers wanting lots of stage 2 ram at a given time. That looks like the following. It splits the available ram equally between the two (or n) workers with disparate exponents. ram of any stage 2 P-1 worker ~ availableram / n. Regardless of exponent.
A perhaps more optimal way to split the available ram would be ram_n ~ availableram * exponent_n/(sum of exponents of workers in stage 2). For example, in the case above, 105M and 332M, ram₁ ~ 110 * 105 / (105+332) = 26.4 GiB; ram₂ ~ 110 * 332 / (105+332) = 83.6 GiB. 26.4GiB/83.6GiB ~105M/332M.

[Jul 21 16:21:46] Waiting 5 seconds to stagger worker starts.
[Jul 21 16:21:52] Worker starting
[Jul 21 16:21:52] Setting affinity to run worker on CPU core #13
[Jul 21 16:21:52] Optimal P-1 factoring of M332222819 using up to 112640MB of memory.
[Jul 21 16:21:52] Assuming no factors below 2^78 and 2 primality tests saved if a factor is found.
[Jul 21 16:21:52] Optimal bounds are B1=2759000, B2=176703000
[Jul 21 16:21:52] Chance of finding a factor is an estimated 6.08%
...
[Jul 21 16:21:56] M332222819 stage 1 is 19.553% complete.
[Jul 21 16:25:24] M332222819 stage 1 is 19.804% complete. Time: 208.451 sec.
...
[Jul 22 11:46:50] M332222819 stage 1 is 99.455% complete. Time: 233.422 sec.
[Jul 22 11:50:40] M332222819 stage 1 is 99.706% complete. Time: 230.289 sec.
[Jul 22 11:54:33] M332222819 stage 1 is 99.957% complete. Time: 232.733 sec.
[Jul 22 11:55:11] M332222819 stage 1 complete. 6403366 transforms. Time: 70394.576 sec.
[Jul 22 11:55:11] Starting stage 1 GCD - please be patient.
[Jul 22 11:58:14] Stage 1 GCD complete. Time: 182.190 sec.
[Jul 22 11:58:14] Available memory is 112587MB.
[Jul 22 11:58:15] D: 462, relative primes: 765, stage 2 primes: 9655948, pair%=87.93
[Jul 22 11:58:15] Using 112478MB of memory.
[Jul 22 12:00:58] Stage 2 init complete. 6971 transforms. Time: 164.592 sec.
[Jul 22 12:06:09] M332222819 stage 2 is 0.177% complete. Time: 310.526 sec.
[Jul 22 12:11:21] M332222819 stage 2 is 0.355% complete. Time: 312.158 sec.
...
[Jul 22 12:47:51] M332222819 stage 2 is 1.604% complete. Time: 315.325 sec.
[Jul 22 12:53:10] M332222819 stage 2 is 1.782% complete. Time: 319.193 sec.
[Jul 22 12:58:25] M332222819 stage 2 is 1.960% complete. Time: 315.494 sec.
[Jul 22 13:00:26] Restarting worker with new memory settings.
[Jul 22 13:00:40] Optimal P-1 factoring of M332222819 using up to 112640MB of memory.
[Jul 22 13:00:40] Assuming no factors below 2^78 and 2 primality tests saved if a factor is found.
[Jul 22 13:00:40] Optimal bounds are B1=2759000, B2=176703000
[Jul 22 13:00:40] Chance of finding a factor is an estimated 6.08%
[Jul 22 13:00:40] 
[Jul 22 13:00:42] Setting affinity to run helper thread 3 on CPU core #16
[Jul 22 13:00:42] Setting affinity to run helper thread 9 on CPU core #22
[Jul 22 13:00:42] Setting affinity to run helper thread 5 on CPU core #18
[Jul 22 13:00:42] Setting affinity to run helper thread 7 on CPU core #20
[Jul 22 13:00:42] Setting affinity to run helper thread 6 on CPU core #19
[Jul 22 13:00:42] Setting affinity to run helper thread 2 on CPU core #15
[Jul 22 13:00:42] Setting affinity to run helper thread 1 on CPU core #14
[Jul 22 13:00:42] Setting affinity to run helper thread 4 on CPU core #17
[Jul 22 13:00:42] Using AVX FFT length 18M, Pass1=1536, Pass2=12K, clm=2, 12 threads
[Jul 22 13:00:42] Setting affinity to run helper thread 10 on CPU core #23
[Jul 22 13:00:42] Setting affinity to run helper thread 11 on CPU core #24
[Jul 22 13:00:42] Setting affinity to run helper thread 8 on CPU core #21
[Jul 22 13:00:45] Available memory is 56322MB.
[Jul 22 13:00:47] D: 420, relative primes: 380, stage 2 primes: 8359345, pair%=80.86
[Jul 22 13:00:47] Using 56176MB of memory.
[Jul 22 13:02:08] Stage 2 init complete. 3998 transforms. Time: 83.241 sec.
[Jul 22 13:02:09] M332222819 stage 2 is 2.035% complete.
[Jul 22 13:07:01] M332222819 stage 2 is 2.209% complete. Time: 292.909 sec.
[Jul 22 13:11:55] M332222819 stage 2 is 2.383% complete. Time: 293.947 sec.
[Jul 22 13:16:47] M332222819 stage 2 is 2.555% complete. Time: 291.975 sec.
[Jul 22 13:21:40] M332222819 stage 2 is 2.730% complete. Time: 292.363 sec.
[Jul 22 13:26:37] M332222819 stage 2 is 2.902% complete. Time: 297.669 sec.

[drkirkby]

I'm trying to see what happens as the saved tests varies, so I set it to 1.05 in worktodo.txt. But mprime reports it is using 1.1. Is mprime using 1.05, and just rounding the output to 2 significant digits, or is it using 1.1? If it is rounding the output, is there any chance of giving an extra two or three decimal places in the reported output? I expect people will start using values slightly over 1.0, to take account of the time to verify the proof.

My interest was to see if I could maximise the equation
https://www.mersenne.org/various/math.php#p-1_factoring
by using values of saved test slightly different from 1.0, since I expect the best value might depend on the speed of access to RAM in stage 2 of the P-1 factoring.

[Uncwilly]

I noticed that setting it to 1.15 also has Prime95 reporting as using 1.1

[kriesel]

Try some of 1.0, 1.05, 1.1, 1.15, 1.2, and note both variation in prime95's indication of tests_saved, and any corresponding variation in the selected bounds, for same or very similar exponents. If tests_saved is being rounded for display only, bounds display will give greater resolution.
If tests_saved is being subjected to a 0.1-unit stairstepping before determining bounds, bounds matching at 0.05 tests-saved differences would confirm that.

Or have a look at the source code.

[pepi37]

If use Prime95 as I use to find PRP on CRUS then I dont need proof files. But I like option that P-1 is little faster. So I can do all I do before except fact to disable creating of proof files. I try all options in undoc.txt but still proof files are created.
Any help?
Version was latest build of Prime95 30.6

[Viliam Furik]

Originally Posted by pepi37

If use Prime95 as I use to find PRP on CRUS then I dont need proof files. But I like option that P-1 is little faster. So I can do all I do before except fact to disable creating of proof files. I try all options in undoc.txt but still proof files are created.
Any help?
Version was latest build of Prime95 30.6

Did you try simply deleting the paths to directories for residues and proofs in the advanced section of the resource limits menu? That might be able to force it to not create proofs. Or the program will be stubborn and will use its home folder. Either way, worth trying.

[pepi37]

Originally Posted by Viliam Furik

Did you try simply deleting the paths to directories for residues and proofs in the advanced section of the resource limits menu? That might be able to force it to not create proofs. Or the program will be stubborn and will use its home folder. Either way, worth trying.

Good idea, but not working, directory path are empty at the start...

[drkirkby]

I must say George, this has some of the best commented C code I have ever seen. It would be nice if there were some instructions for building on linux, but I eventually worked it out.

$ cd gwnum
$ make -f make64 
$ cd ../linux64
$ make

Prior to realising that the gwnum library had to be built first, I had a few problems, as I was trying to change linux64/makefile unnecessarily to use the gwnum.a included with the source distribution.

But the actual C code is very readable. I found it more readable than some of my own code that I wrote years ago!

Is there any chance you giving us an extra digit or two in the probability of finding a factor, by changing this line in ecm.c?

        sprintf (buf, "Chance of finding a factor is an estimated %.3g%%\n", prob * 100.0);

I was keen to know if giving more RAM to stage 2 of P-1 was beneficial or not. For that I need the probability of finding the factor, along with the time to execute the P-1 factoring and the time to perform the PRP test. An extra digit or two would be useful. Fortunately I can don't need to re-run my tests, as I can simply increase the number of digits, then exit the code, without repeating the test.
I've not actually run my modified mprime yet, as I'm benchmarking a PRP test and don't want to change the load on the machine, which would change the completion times.