ECM for CUDA GPUs in latest GMP-ECM ? - Page 43

EdH · 2019-10-25, 00:46

Quote:

Originally Posted by Dylan14

Hmm... could you try cat cuda.h to see what version it is?
If it is larger than 3 (which is most likely is) then you may have to fiddle around with the configure script so it looks for a higher version.

I'll do a cat in a bit (after I recover from an extended power outage - one of the problems with having a bunch of ancient machines, some of which don't wake back up right). Meanwhile, I had tried playing around with some of the code in the configure file in an attempt to swap failure with success, but I wasn't able to get anywhere - I'm a bit too far over my head.

Thanks!

EdH · 2019-10-25, 03:09

@Dylan14:

Good Call! The one I was pointing to was something from last century. I found one in a very current folder that got me a couple steps further. Now I have to work on libraries. But I had to stop for now.

Thanks!

EdH · 2019-10-26, 01:48

This #%$@ thing is fighting me all the way!

Last straw!:

Code:

checking for compatibility between gcc and nvcc... no
configure: error: gcc version is not compatible with nvcc

chalsall · 2019-10-26, 02:04

Quote:

Originally Posted by EdH

This #%$@ think is fighting me all the way!

As is its job.

You're smarter than it is.

Prove it.

EdH · 2019-10-26, 02:18

Quote:

Originally Posted by chalsall

As is its job.

You're smarter than it is.

Prove it.

But, I think it is more patient.

However, a bit after I posted, I thought, "I did get further than last night."

chalsall · 2019-10-26, 02:39

Quote:

Originally Posted by EdH

However, a bit after I posted, I thought, "I did get further than last night."

And that is exactly how to approach this kind of "problem space".

Run experiments. Observe results.

Repeat as necessary...

Give it a little bit of time, and you'll begin "lucid dreaming" about stuff like this.

It's kinda cool waking up with "well, obviously, that's how you'd do that" before even the first coffee of the morning...

EdH · 2019-10-26, 03:17

Success! Thanks for the words of encouragement.

I'll see if it will repeat tomorrow and figure out where to post here if success is repeatable...

EdH · 2019-10-26, 15:27

Quote:

Originally Posted by EdH

. . .
I'll see if it will repeat tomorrow and figure out where to post here if success is repeatable...

I added it as a new thread to my list of How I... threads in the blog area:

How I Compile the GPU branch of GMP-ECM in a Colaboratory Session

EdH · 2019-11-05, 18:51

This question is based primarily on my playing with Colab and my GPU-GMP-ECM setup mentioned earlier.

If I run the GPU version, it will saturate the GPU with as many curves as cores available and run stage 1. But, in a recent test case, that was over 4k cores. If I were to fully process all those it would mean about 30 minutes for the stage 1 part on the GPU (for my chosen number/B1), followed by an awfully long CPU processing time for stage 2 to finish all those runs with only two CPU cores handling them.

Is there much value n running just stage 1 ECM, realizing that unless I keep the residues for later followup, all those stage 1 runs will have to be repeated at some point?

fivemack · 2019-11-05, 20:01

Quote:

Originally Posted by EdH

This question is based primarily on my playing with Colab and my GPU-GMP-ECM setup mentioned earlier.

If I run the GPU version, it will saturate the GPU with as many curves as cores available and run stage 1. But, in a recent test case, that was over 4k cores. If I were to fully process all those it would mean about 30 minutes for the stage 1 part on the GPU (for my chosen number/B1), followed by an awfully long CPU processing time for stage 2 to finish all those runs with only two CPU cores handling them.

Is there much value n running just stage 1 ECM, realizing that unless I keep the residues for later followup, all those stage 1 runs will have to be repeated at some point?

Don't just run stage 1! Keep the residues, they are pretty tiny - less than 500 bytes per curve. Use something like

Code:

ecm -v -v -gpudevice 0 -gpu -save e.$u.s1 85e7 1

then take the .s1 files home, split the lines up however you like and let your other cores at them

Code:

ecm -maxmem 3000 -resume $u 85e7 < ../N > $u.s2

Or post the .s1 files somewhere, link to them from this forum and let people at them.

I found it was 43.6 hours to do 1792 stage-1 curves on a GTX1080Ti and about 1070 seconds on one core of Xeon Silver 4114 to run stage 2 on one curve (so you needed about 12 such cores to keep up with the GPU)

EdH · 2019-11-05, 20:40

Thanks! I must have gotten something mixed up in my earlier testing. (That's happening a lot , lately.) I thought I ran some 11e7 stage 1 tests on a Colab session in about 40 minutes for 832 curves, but I'm coming up on 2 hours this time. I must have been using a smaller candidate before.

I will modify my routine to save residues, then and see what other mischief I can come up with.

Thanks, again!

2019-10-26, 01:48	#465
EdH "Ed Hall" Dec 2009 Adirondack Mtns 2·3³·67 Posts	This #%$@ thing is fighting me all the way! Last straw!: Code: checking for compatibility between gcc and nvcc... no configure: error: gcc version is not compatible with nvcc Last fiddled with by EdH on 2019-10-26 at 02:15 Reason: I couldn't even spell! Must be tired. . .

2019-11-05, 18:51	#471
EdH "Ed Hall" Dec 2009 Adirondack Mtns 2·3³·67 Posts	How Valuable Is Stage 1 In the Overall ECM Process This question is based primarily on my playing with Colab and my GPU-GMP-ECM setup mentioned earlier. If I run the GPU version, it will saturate the GPU with as many curves as cores available and run stage 1. But, in a recent test case, that was over 4k cores. If I were to fully process all those it would mean about 30 minutes for the stage 1 part on the GPU (for my chosen number/B1), followed by an awfully long CPU processing time for stage 2 to finish all those runs with only two CPU cores handling them. Is there much value n running just stage 1 ECM, realizing that unless I keep the residues for later followup, all those stage 1 runs will have to be repeated at some point?

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2019-10-25, 03:09	#464
EdH "Ed Hall" Dec 2009 Adirondack Mtns 7042₈ Posts	@Dylan14: Good Call! The one I was pointing to was something from last century. I found one in a very current folder that got me a couple steps further. Now I have to work on libraries. But I had to stop for now. Thanks!

2019-10-26, 03:17	#469
EdH "Ed Hall" Dec 2009 Adirondack Mtns 7042₈ Posts	Success! Thanks for the words of encouragement. I'll see if it will repeat tomorrow and figure out where to post here if success is repeatable...

2019-11-05, 20:40	#473
EdH "Ed Hall" Dec 2009 Adirondack Mtns 2·3³·67 Posts	Thanks! I must have gotten something mixed up in my earlier testing. (That's happening a lot , lately.) I thought I ran some 11e7 stage 1 tests on a Colab session in about 40 minutes for 832 curves, but I'm coming up on 2 hours this time. I must have been using a smaller candidate before. I will modify my routine to save residues, then and see what other mischief I can come up with. Thanks, again!