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-   -   mfaktc: a CUDA program for Mersenne prefactoring (https://www.mersenneforum.org/showthread.php?t=12827)

kriesel 2020-10-21 16:56

[QUOTE=Viliam Furik;560519]Either way, I am not satisfied with the result.[/QUOTE]I wonder what gpu-z, nvidia-smi or similar utility would show for the gpu utilization/load, and whether mfaktc.ini was tuned for the new fast gpus (>>128M GpuSieveSize, etc)
Also the classes output are numerous per second in the posted benchmark, which if on a rotating disk would slow things down; try an SSD or ramdisk or higher bit level or less_classes. Even on a well tuned RTX2080 I see throughput advantage to multiple mfaktc instances. These effects are slight but measurable even at GTX1050Ti. The faster the gpu, the stronger the effects is the trend I've observed on Windows over a gpu speed ratio of 10:1 or more.

petrw1 2020-10-21 17:25

[QUOTE=Viliam Furik;560519]Why so poor result? I get about 4900 GHzD/D with the same work. It should be at least 10000 GHzD/D for the 3090, no? It has more than double the FP32 throughput.

It is most probably one of these two reasons:
1. The shared INT32 and FP32 cores don't play nicely with mfaktc - either incompatible code or the cores not fulfilling their promise
2. Memory bottleneck

Either way, I am not satisfied with the result.[/QUOTE]

Did you try the version that supports 2047 classes?
My 2080Ti went from 4,000 to 4,500 Ghz/Day with that version.

Viliam Furik 2020-10-21 17:30

[QUOTE=petrw1;560569]Did you try the version that supports 2047 classes?
My 2080Ti went from 4,000 to 4,500 Ghz/Day with that version.[/QUOTE]

Who, me? I am already using the 2047 version, as recommended by you. The mentioned 4900 GHz-D/D is from RTX 2080Ti, for the same workload as the 3090 was tested with.

James Heinrich 2020-10-22 02:28

[QUOTE=Neutron3529;560502]I bought a RTX 3090[/QUOTE]Also, I'm still anxiously waiting for your gpuowl and cudalucas benchmarks, please...

moebius 2020-10-22 04:06

[QUOTE=James Heinrich;560639]Also, I'm still anxiously waiting for your gpuowl and cudalucas benchmarks, please...[/QUOTE]
And yet, the expected performance values for LL/PRP ​​on the [URL="https://www.mersenne.ca/cudalucas.php"]https://www.mersenne.ca/cudalucas.php[/URL] page are still suspect to me. You can't seriously tell me a Tesla K-80 would be almost at the same Level as a Tesla P100 (PCIe 16GB).They are miles apart! Likewise,as much as I know, a Radeon VII isn't faster than a Tesla V100. In my opinion, this confuses the users of your site. I hope there are no bad purchases in the end?

James Heinrich 2020-10-22 04:15

[QUOTE=moebius;560645]And yet, the expected performance values ​​on the [URL="https://www.mersenne.ca/cudalucas.php"]https://www.mersenne.ca/cudalucas.php[/URL] page are still suspect to me.[/QUOTE]They might be. Hence my perpetual request for benchmarks.

Neutron3529 2020-10-22 07:04

1 Attachment(s)
[QUOTE=James Heinrich;560541]I've looked at the code again and clearly I'm missing something because I think it should be working as I intended (but clearly it isn't). It's also difficult to test because that section of code will only get processed when a new factor is submitted (my logic works fine in my test environment, but something different is happening on the server). I have added a couple of debug lines that might help me track down the problem, if you see them next time you (collective "you", anyone reading this) submit a factor please email me either a copy-paste or screenshot of the output.[/QUOTE]
Do you want this?
[ATTACH]23592[/ATTACH]
the server seems not to work with a TF result.


these two lines could trigger this BUG more than once and stop the upcoming results.

[CODE]
M104186261 has a factor: 21599873573633423090833 [TF:74:75:mfaktc 0.21 barrett76_mul32_gs]
found 1 factor for M104186261 from 2^74 to 2^75 [mfaktc 0.21 barrett76_mul32_gs][/CODE]You could test it until the BUG is removed.


---



Found 8 lines to process.
[COLOR=darkgreen]processing: TF factor 21599873573633423090833 for [URL="https://www.mersenne.org/M104186261"]M104186261[/URL] (274-275) [range fully factored][/COLOR]
DEBUG: TF.range-complete credit(1) = 7.1037506824902
DEBUG: TF.range-complete credit(2) = 36.723102738304

aheeffer 2020-10-22 08:10

[QUOTE=James Heinrich;560541]. I have added a couple of debug lines that might help me track down the problem, if you see them next time you (collective "you", anyone reading this) submit a factor please email me either a copy-paste or screenshot of the output.[/QUOTE]

[CODE]
processing: TF factor 410022995157224015562287 for M333946237 (278-279) [range fully factored]
DEBUG: TF.range-complete credit(1) = 80.66706346138
DEBUG: TF.range-complete credit(2) = 183.31299318089
DEBUG: TF.range-complete credit(3) = 183.31299318089
DEBUG: TF.range-complete credit(4) = 183.31299318089
Please report these debug lines to james@mersenne.ca or post at https://www.mersenneforum.org/showthread.php?p=560500
CPU credit is 80.6671 GHz-days.
[/CODE]

2M215856352p1 2020-10-22 08:36

1 Attachment(s)
[QUOTE=James Heinrich;560541]I've looked at the code again and clearly I'm missing something because I think it should be working as I intended (but clearly it isn't). It's also difficult to test because that section of code will only get processed when a new factor is submitted (my logic works fine in my test environment, but something different is happening on the server). I have added a couple of debug lines that might help me track down the problem, if you see them next time you (collective "you", anyone reading this) submit a factor please email me either a copy-paste or screenshot of the output.[/QUOTE]

Here is another test case.

Neutron3529 2020-10-22 12:46

[QUOTE=James Heinrich;560541]I've looked at the code again and clearly I'm missing something because I think it should be working as I intended (but clearly it isn't). It's also difficult to test because that section of code will only get processed when a new factor is submitted (my logic works fine in my test environment, but something different is happening on the server). I have added a couple of debug lines that might help me track down the problem, if you see them next time you (collective "you", anyone reading this) submit a factor please email me either a copy-paste or screenshot of the output.[/QUOTE]
[COLOR=darkgreen]processing: TF no-factor for [URL="https://www.mersenne.org/M114899527"]M114899527[/URL] (274-275)[/COLOR]
[COLOR=blue]CPU credit is 33.2990 GHz-days.[/COLOR]
[COLOR=darkgreen]processing: TF factor 23024239007594549773417 for [URL="https://www.mersenne.org/M114899501"]M114899501[/URL] (274-275) [range fully factored][/COLOR]
DEBUG: TF.range-complete credit(1) = 9.5092580373447
DEBUG: TF.range-complete credit(2) = 33.29903727452
DEBUG: TF.range-complete credit(3) = 33.29903727452
DEBUG: TF.range-complete credit(4) = 33.29903727452
Please report these debug lines to [EMAIL="james@mersenne.ca"]james@mersenne.ca[/EMAIL] or post at [URL]https://www.mersenneforum.org/showthread.php?p=560500[/URL][COLOR=blue]CPU credit is 9.5093 GHz-days.[/COLOR]
[COLOR=darkgreen]processing: TF factor 21599873573633423090833 for [URL="https://www.mersenne.org/M104186261"]M104186261[/URL] (274-275) [range fully factored][/COLOR]
DEBUG: TF.range-complete credit(1) = 7.1037506824902
DEBUG: TF.range-complete credit(2) = 36.723102738304
DEBUG: TF.range-complete credit(3) = 36.723102738304
DEBUG: TF.range-complete credit(4) = 36.723102738304
Please report these debug lines to [EMAIL="james@mersenne.ca"]james@mersenne.ca[/EMAIL] or post at [URL]https://www.mersenneforum.org/showthread.php?p=560500[/URL][COLOR=blue]Already have factor 21599873573633423090833 for M104186261 CPU credit is 7.1038 GHz-days.[/COLOR]
Done processing:
* Parsed 44 lines.
* Found 0 datestamps.

James Heinrich 2020-10-22 12:57

Thanks guys, I [I]think[/I] (again) that I've found the problem. In this case my code was working as expected and overriding the correct amount of credit, but the message displayed to the user was pre-written elsewhere using the default credit amount, I just needed to also rewrite the user message. Can one of the people who've posted above (or anyone with a new TF factor in a fully-factored range reported in the last 8h or more recently) confirm if the GHz-days credit in [url=https://www.mersenne.org/results/?extf=1&exp1=1&execm=1&exll=1&exprp=1&excert=1&exp_lo=2&exp_hi=&limit=100]your Account Result Details page[/url] shows the higher (correct) or lower (incorrect) amount of credit for the TF-F (range-fully-factored) result?


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