mfaktc: a CUDA program for Mersenne prefactoring - Page 179

firejuggler · 2012-12-26, 09:05

3# as well, even if i'm not really active on Gpu front at this time

ET_ · 2012-12-26, 10:47

#3 for me, even if I used mmff 0.26 with no -gs switch, and it appeared to sieve on GPU.

Luigi

James Heinrich · 2012-12-26, 11:57

Quote:

Originally Posted by axn

Intelligent/Smart option -- Do a selftest and pick the one with highest thruput.

I'm not sure if that would differ from #3 -- I'm not sure if there are cases where GPU sieving would be slower that CPU sieving. Possibly on a very-slow GPU (GT 620 or similar) with a very fast CPU -- I'm not sure if Oliver/George have looked into the cutoff points of efficiency.

It has been determined that CC 1.x GPUs have poor throughput for GPU sieving to the point where it makes no sense so it's never available, but for CC 2.0+ the benefit is significant.

The value for GPUSievePrimes might be a viable target for auto-adjustment, but in brief testing I found very little difference in throughput using different values.

VictordeHolland · 2012-12-26, 13:09

Can somebody give an rough indication of when the 0.20 'production' client will be released? I know it is all done in your spare time, but I (and probably others) are eagerly waiting for this big improvement.

TheJudger · 2012-12-26, 16:35

Hello,

Quote:

Originally Posted by James Heinrich

I'm not sure if that would differ from #3 -- I'm not sure if there are cases where GPU sieving would be slower that CPU sieving. Possibly on a very-slow GPU (GT 620 or similar) with a very fast CPU -- I'm not sure if Oliver/George have looked into the cutoff points of efficiency.

OK, we have a winner: option #3.

No, no automatic switching between CPU and GPU sieving, I like simple solutions.

Oliver

TheJudger · 2012-12-26, 16:40

Quote:

Originally Posted by VictordeHolland

Can somebody give an rough indication of when the 0.20 'production' client will be released? I know it is all done in your spare time, but I (and probably others) are eagerly waiting for this big improvement.

When it's done!

Oliver

P.S. I want to finish v0.20 this year. Add a week or two for testing where I give it to a few people and if no problems are found I'll release it.

xtreme2k · 2012-12-27, 10:02

Hey guys,

Got a new 670GTX (upgrade from 460GTX). I am now cracking at approx 195-200M/s (vs 150M/s) which is pretty poor given the upgrade. NV really made the new chip a pure gaming chip with crappy compute performance and its really showing.

The only advantage I know would be this GPU uses similiar power vs the 460GTX (if not only slightly more).

Does mfaktc work on dual GPU systems with separate GPU? How does one assign each GPU (if this is possible). I was thinking of plugging in the 460GTX purely for compute use? What do you guys think?

LaurV · 2012-12-27, 10:04

Yes, you can plug both of them in, and depending on your CPU, use more instances of mfaktc for each.
Use the "-d x" switch to say which GPU be used by which instance, substitute x with the gpu number. Is in the docs, and right in this very thread too, few pages back.

Sutton Shin · 2012-12-27, 10:07

Where is the program for windows 7 x64?

I KNOW that it is a stupid question. I am too lazy to go through 86 pages of posts.

Dubslow · 2012-12-27, 10:33

Quote:

Originally Posted by Sutton Shin

Where is the program for windows 7 x64?

I KNOW that it is a stupid question. I am too lazy to go through 86 pages of posts.

Very stupid. Even if you're too lazy to go through posts, Google is your friend. (First or third link are perfectly useful.)

Quote:

Originally Posted by LaurV

Yes, you can plug both of them in, and depending on your CPU, use more instances of mfaktc for each.
Use the "-d x" switch to say which GPU be used by which instance, substitute x with the gpu number. Is in the docs, and right in this very thread too, few pages back.

In other words, RTFM.

____________________________________________________________________________

TheJudger · 2012-12-27, 11:55

Quote:

Originally Posted by xtreme2k

Hey guys,

Got a new 670GTX (upgrade from 460GTX). I am now cracking at approx 195-200M/s (vs 150M/s) which is pretty poor given the upgrade. NV really made the new chip a pure gaming chip with crappy compute performance and its really showing.

Well, you're limited by your CPU, a single core can't feed your GTX 670. You can either start a second instance using a second CPU core our wait for mfaktc 0.20 and use GPU sieving. Depending on the exponent and bitlevel a GTX 670 should yield > 300M/s in best case (barrett76 kernel).
And you're right, for applications which make heavy use of integer instructions (like mfaktc), the newer chips are not so good. Anyway the energy efficiency (performance per watt while running mfaktc) is very good.

Oliver

2012-12-27, 10:02	#1965
xtreme2k Aug 2002 256₈ Posts	Hey guys, Got a new 670GTX (upgrade from 460GTX). I am now cracking at approx 195-200M/s (vs 150M/s) which is pretty poor given the upgrade. NV really made the new chip a pure gaming chip with crappy compute performance and its really showing. The only advantage I know would be this GPU uses similiar power vs the 460GTX (if not only slightly more). Does mfaktc work on dual GPU systems with separate GPU? How does one assign each GPU (if this is possible). I was thinking of plugging in the 460GTX purely for compute use? What do you guys think? Attached Thumbnails

2012-12-27, 10:04	#1966
LaurV Romulan Interpreter Jun 2011 Thailand 3×3,221 Posts	Yes, you can plug both of them in, and depending on your CPU, use more instances of mfaktc for each. Use the "-d x" switch to say which GPU be used by which instance, substitute x with the gpu number. Is in the docs, and right in this very thread too, few pages back. Last fiddled with by LaurV on 2012-12-27 at 10:06

2012-12-27, 10:07	#1967
Sutton Shin Sep 2012 17 Posts	Stupid Question Where is the program for windows 7 x64? I KNOW that it is a stupid question. I am too lazy to go through 86 pages of posts. Last fiddled with by Sutton Shin on 2012-12-27 at 10:09

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2012-12-26, 09:05	#1959
firejuggler Apr 2010 Over the rainbow 2×1,303 Posts	3# as well, even if i'm not really active on Gpu front at this time

2012-12-26, 10:47	#1960
ET_ Banned "Luigi" Aug 2002 Team Italia 61·79 Posts	#3 for me, even if I used mmff 0.26 with no -gs switch, and it appeared to sieve on GPU. Luigi

2012-12-26, 13:09	#1962
VictordeHolland "Victor de Hollander" Aug 2011 the Netherlands 2³·3·7² Posts	Can somebody give an rough indication of when the 0.20 'production' client will be released? I know it is all done in your spare time, but I (and probably others) are eagerly waiting for this big improvement.