ECM for CUDA GPUs in latest GMP-ECM ?

[wombatman]

Originally Posted by xilman

I'll see what I can do. For better or worse I seem to have ended up with the job of maintaining GPU-ECM. Any assistance with that task will be much appreciated. In particular, evidence of inadequacies of the software will be useful. Even more useful will be contributions to its enhancement.

BTW, and AFAIK, the 512-bit version is really 506-bit limited. One of the things on my to-do list is to allow for more versions. Ideally the end-user shouldn't have to predetermine the size of the arithmetic. Another WIBNI is to implement stage 2 on the GPU. That might be the easier of the two. I would also like to extend the ECMNET client to use a GPU where available.

I can do little to nothing on the programming side of things, but I'm always happy to try and help out with testing. Please feel free to PM me when or if you want help there.

[VBCurtis]

Originally Posted by wombatman

I'll run the lower levels tonight as I get a chance to. That will provide an approximate trend, as I've noticed that the time involved for higher B1s is roughly linear with B1.

Timing is within 1% of linear from 60M to 1200M (the smallest and largest bounds I've used for GPU-ECM). So, we can benchmark by testing a single B1 bound across cards.

To make the bench short-ish, how about the t50 standard B1 = 43M? I'll report 750ti numbers tomorrow.

[wombatman]

I checked B1=3M and 11M, and they were also within 1% of each other (0.6%, to be precise), so we could probably use one of those to decrease the time. If reproducibility is a concern, B1=3M could be run, say, 3 times and averaged.

[wombatman]

Times for the C197 bsquared put up on a GTX980Ti:

B1=3M: 776.75s
B1=11M: 2830.76s
B1=43M: 11235.902s

As noted by Curtis, these all scale linearly with B1 within ~1%.

[bsquared]

Originally Posted by wombatman

Times for the C197 bsquared put up on a GTX980Ti:

B1=3M: 776.75s
B1=11M: 2830.76s
B1=43M: 11235.902s

As noted by Curtis, these all scale linearly with B1 within ~1%.

Thank you, much appreciated. How many curves does that card run in parallel? I'm trying to gauge the throughput of these things...

[wombatman]

Originally Posted by bsquared

Thank you, much appreciated. How many curves does that card run in parallel? I'm trying to gauge the throughput of these things...

1408 at once. Also, please note that those timings are just for Stage 1.

[bsquared]

Originally Posted by wombatman

1408 at once. Also, please note that those timings are just for Stage 1.

Yep, understood. Thanks - this is very helpful!

[wombatman]

Originally Posted by bsquared

Yep, understood. Thanks - this is very helpful!

Does this mean YAFU may be incorporating GPU-based ECM?

[chris2be8]

Output from the last job I ran with B1=43M:

  Wed 27 Sep 2017 03:16:08 BST ecm to 50 digits stage 1 step 1 of 2 ended
GMP-ECM 7.0-dev [configured with GMP 5.1.3, --enable-asm-redc, --enable-gpu, --enable-assert] [ECM]
Input number is 3129333620258940486330629139630925933631807344645219843266754670086579137577512492047980091055198974792305750155580720314468906941756462912147587701714558353912867079793467240454311904331638921 (193 digits)
Using B1=43000000, B2=1, sigma=3:2949756002-3:2949756417 (416 curves)
Computing 416 Step 1 took 251097ms of CPU time / 5018458ms of GPU time
  Wed 27 Sep 2017 04:42:07 BST ecm to 50 digits stage 1 step 2 of 2 ended

The GPU does 416 curves at a time.

The script waits for the stage 2 tasks to finish before starting the next stage 1 run. But the last save file says the residues were saved at Wed Sep 27 04:39:49 2017 so the run was from Wed 27 Sep 2017 03:16:08 to Wed Sep 27 04:39:49.

The GPU is a GeForce GTX 970 according to nvidia-smi:

Thu Sep 28 16:56:39 2017
+------------------------------------------------------+
| NVIDIA-SMI 352.39     Driver Version: 352.39         |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 970     Off  | 0000:01:00.0     Off |                  N/A |
|  0%   54C    P0    34W / 201W |     15MiB /  4095MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|=============================================================================|
|  No running processes found                                                 |
+-----------------------------------------------------------------------------+

Chris

[bsquared]

Originally Posted by wombatman

Does this mean YAFU may be incorporating GPU-based ECM?

No... but possibly a competing technology
No promises...

[wombatman]

Originally Posted by bsquared

No... but possibly a competing technology
No promises...

https://imgur.com/uu9pmDP

Edit: And when or if you want some testing done, feel free to PM