mfaktc: a CUDA program for Mersenne prefactoring - Page 220

James Heinrich · 2014-10-22, 20:19

Does this mean GPU sieving will be available below 2^64 for large exponents, such as my own pet project of 1000M-4296M? I only need support down to 2^52 since everything has been done below that, but if GPU sieving could be enabled... that would be of tremendous benefit

Bdot · 2014-10-22, 20:55

mfakto's _gs kernels start at 2⁶⁰, also for your pet project, James.

So far, I was not approached to lower that limit, and I don't have that on my plan (yet).

Code:

got assignment: exp=4201971233 bit_min=66 bit_max=67 (0.00 GHz-days)
Starting trial factoring M4201971233 from 2^66 to 2^67 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 22:42 | 4611 100.0% |  0.002   0m00s |    160.06    80181    0.00%
no factor for M4201971233 from 2^66 to 2^67 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  2.751s (111.71 GHz-days / day)

Maybe you have a factor (> 2⁶⁰) for me that I could verify to find?

edit2: Using less-classes, that same thing is even more fun:

Code:

got assignment: exp=4201971233 bit_min=66 bit_max=67 (0.00 GHz-days)
Starting trial factoring M4201971233 from 2^66 to 2^67 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:02 |  412 100.0% |  0.009   0m00s |    355.68    80181    0.00%
no factor for M4201971233 from 2^66 to 2^67 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.995s (308.85 GHz-days / day)

James Heinrich · 2014-10-22, 21:06

Quote:

Originally Posted by Bdot

Maybe you have a factor (> 2⁶⁰) for me that I could verify to find?

The list of exponents-with-many-factors has many entries you can pick from. I can give you a pile of more specific exponents if you're interested. Here's a tiny sample with factors slightly larger than 60 bits:

Code:

Factor=2001862367,60,61
Factor=2000098873,60,61
Factor=2004561407,60,61
Factor=2005844293,60,61
Factor=2009094883,60,61
Factor=2003270579,60,61
Factor=2006109223,60,61
Factor=2008886611,60,61
Factor=2004315961,60,61
Factor=2001388097,60,61

Bdot · 2014-10-22, 21:11

Code:

got assignment: exp=2001862367 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2001862367 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  417 100.0% |  0.001   0m00s |    104.99    80181    0.00%
M2001862367 has a factor: 1153068867805081159

found 1 factor for M2001862367 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.167s (60.35 GHz-days / day)

got assignment: exp=2000098873 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2000098873 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |   75  18.8% |  0.001   0m00s |    105.08    80181    0.00%
M2000098873 has a factor: 1153427718610610551
Oct 22 23:08 |  416 100.0% |  0.001   0m00s |    105.08    80181    0.00%
found 1 factor for M2000098873 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.149s (67.70 GHz-days / day)

got assignment: exp=2004561407 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2004561407 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  232  56.3% |  0.001   0m00s |    104.85    80181    0.00%
M2004561407 has a factor: 1153386835577909609
Oct 22 23:08 |  417 100.0% |  0.001   0m00s |    104.85    80181    0.00%
found 1 factor for M2004561407 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.147s (68.47 GHz-days / day)

got assignment: exp=2005844293 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2005844293 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  116  29.2% |  0.001   0m00s |    104.78    80181    0.00%
M2005844293 has a factor: 1153405062405321977
Oct 22 23:08 |  416 100.0% |  0.001   0m00s |    104.78    80181    0.00%
found 1 factor for M2005844293 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.145s (69.37 GHz-days / day)

got assignment: exp=2009094883 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2009094883 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |   53  14.6% |  0.001   0m00s |    104.61    80181    0.00%
M2009094883 has a factor: 1153540764802817159
Oct 22 23:08 |  417 100.0% |  0.001   0m00s |    104.61    80181    0.00%
found 1 factor for M2009094883 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.146s (68.78 GHz-days / day)

got assignment: exp=2003270579 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2003270579 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  300  70.8% |  0.001   0m00s |    104.91    80181    0.00%
M2003270579 has a factor: 1153716299952772441
Oct 22 23:08 |  417 100.0% |  0.001   0m00s |    104.91    80181    0.00%
found 1 factor for M2003270579 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.146s (68.98 GHz-days / day)

got assignment: exp=2006109223 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2006109223 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  152  35.4% |  0.001   0m00s |    104.77    80181    0.00%
M2006109223 has a factor: 1153764818690030153
Oct 22 23:08 |  416 100.0% |  0.001   0m00s |    104.77    80181    0.00%
found 1 factor for M2006109223 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.145s (69.36 GHz-days / day)

got assignment: exp=2008886611 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2008886611 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  189  45.8% |  0.001   0m00s |    104.62    80181    0.00%
M2008886611 has a factor: 1153863845653352359
Oct 22 23:08 |  416 100.0% |  0.001   0m00s |    104.62    80181    0.00%
found 1 factor for M2008886611 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.148s (67.86 GHz-days / day)

got assignment: exp=2004315961 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2004315961 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  291  70.8% |  0.001   0m00s |    104.86    80181    0.00%
M2004315961 has a factor: 1154230767950158183
Oct 22 23:08 |  416 100.0% |  0.001   0m00s |    104.86    80181    0.00%
found 1 factor for M2004315961 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.146s (68.95 GHz-days / day)

got assignment: exp=2001388097 bit_min=60 bit_max=61 (0.00 GHz-days)
Starting trial factoring M2001388097 from 2^60 to 2^61 (0.00GHz-days)
Using GPU kernel "cl_barrett15_69_gs_2"
Date    Time | class   Pct |   time     ETA | GHz-d/day    Sieve     Wait
Oct 22 23:08 |  163  39.6% |  0.001   0m00s |    105.01    80181    0.00%
M2001388097 has a factor: 1154536360470905183
Oct 22 23:08 |  415 100.0% |  0.001   0m00s |    105.01    80181    0.00%
found 1 factor for M2001388097 from 2^60 to 2^61 [mfakto 0.15pre4-Win cl_barrett15_69_gs_2]
tf(): total time spent:  0.146s (69.05 GHz-days / day)

TheJudger · 2014-10-22, 21:55

Hi James,

Quote:

Originally Posted by James Heinrich

Does this mean GPU sieving will be available below 2^64 for large exponents, such as my own pet project of 1000M-4296M? I only need support down to 2^52 since everything has been done below that, but if GPU sieving could be enabled... that would be of tremendous benefit

Yes, will use the "slow" 75bit schoolbook division kernel in 0.21 below 2⁶⁴ but anyway, GPU sieving is possible and feasible.
Slowish GT 630 (GK208) @900MHz:

Code:

M2001862367 has a factor: 1153068867805081159
found 1 factor for M2001862367 from 2^40 to 2^64 [mfaktc 0.21-pre7 75bit_mul32_gs]
tf(): total time spent:  8.702s

no factor for M2001862367 from 2^64 to 2^66 [mfaktc 0.21-pre7 barrett76_mul32_gs]
tf(): total time spent: 11.213s

Oliver

Bdot · 2014-10-22, 22:12

But back to Oliver's question ...

Quote:

Originally Posted by TheJudger

Comments?

I'd vote for 3.

In combination with your other plan to drop CC 1.x support, there should be sufficient shared memory to at least run, maybe not at best performance. Insufficient shared memory can also be detected, and lowering GPUSieveProcessSize can counter that.

But if you go for 4C (or B), the user also has to lower GPUSievePrimes, and may run into the same trouble.

Ralf Recker · 2014-10-24, 15:44

Quote:

Originally Posted by Ralf Recker

I hope next time NVIDIA tests their cards and drivers on boxes with 32 GB RAM installed.

I had to use msconfig to tell windows to use only 30 GB on boot to avoid a bunch of crashes.

Seems that the 344.48 driver fixed the issue.

Karl M Johnson · 2014-10-28, 07:24

Quote:

Originally Posted by Ralf Recker

Seems that the 344.48 driver fixed the issue.

Another confirmation from me.

wombatman · 2014-11-05, 05:26

How do I enable less classes? I can compile for Windows 7 64-bit with no issue. Just wasn't clear what I needed to enable/disable to get that and try it out. Thanks!

Mark Rose · 2014-11-05, 05:39

Quote:

Originally Posted by wombatman

How do I enable less classes? I can compile for Windows 7 64-bit with no issue. Just wasn't clear what I needed to enable/disable to get that and try it out. Thanks!

Remove

Code:

#define MORE_CLASSES

in params.h and recompile.

wombatman · 2014-11-05, 13:18

Much appreciated!

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2014-10-22, 20:19	#2410
James Heinrich "James Heinrich" May 2004 ex-Northern Ontario 23×149 Posts	Does this mean GPU sieving will be available below 2^64 for large exponents, such as my own pet project of 1000M-4296M? I only need support down to 2^52 since everything has been done below that, but if GPU sieving could be enabled... that would be of tremendous benefit

2014-11-05, 05:26	#2418
wombatman I moo ablest echo power! May 2013 13×137 Posts	How do I enable less classes? I can compile for Windows 7 64-bit with no issue. Just wasn't clear what I needed to enable/disable to get that and try it out. Thanks!

2014-11-05, 13:18	#2420
wombatman I moo ablest echo power! May 2013 6F5₁₆ Posts	Much appreciated!