mfaktc: a CUDA program for Mersenne prefactoring

[James Heinrich]

Originally Posted by kriesel

Note also there's no work or results coordination site for Mersenne hunting at exponents above 2³².

Mostly because there's no GPU program I know of that supports large exponents.
But as you say, there's a lot of work before that point. Something in the order of 18,000,000,000,000 GHz-days of TF effort just between 10⁹ and 2³² exponents (not counting what's still left in the current <1000M PrimeNet range).

[kriesel]

Originally Posted by James Heinrich

Mostly because there's no GPU program I know of that supports large exponents.
But as you say, there's a lot of work before that point. Something in the order of 18,000,000,000,000 GHz-days of TF effort just between 10⁹ and 2³² exponents (not counting what's still left in the current <1000M PrimeNet range).

So in other words, about 18 billion GTX1080-days, plus about 2 billion for the up to a billion exponent, 20 billion total GTX1080-days, and the aggregate throughput seen by PrimeNet of all of GIMPS amounts to about 150 to 180 GTX1080s at 1000GhzD/day (past day or month). 2x10¹⁰/180/365 = 304,000 years. We're counting significantly on Moore's Law to get through that in a century or so. (Something above 11 doublings, soon, which is not justified by current feature sizes and practical further scaling downward.)

[storm5510]

Originally Posted by kriesel

Re your GTX1080, how do you know you don't simply have very good cooling? What does TechPowerUp GPU-Z or CPUID HWMonitor say about gpu % load and reasons for it being less than 95-100%? Are you running high enough bit depths, and/or the less-classes version, or running on a solid state disk, so that I/O is not limiting throughput?

Less-classes for James Heinrich's project. GPU-Z says 98% load. I told James I would finish the 3990M group to 2⁷¹, and I will. Very good cooling? This case has four fans which are rather noisy. So, yes, there is good cooling. SSD, no, but the next best thing, a RAM drive, at James' suggestion.

The extended limit for factoring was a passing thought. There used to be a member here named Luigi, a.k.a. E.T. Back in 2007, he wrote a little program called Factor5. It is not used much now. I tried to find a ceiling for what it would accept as an exponent and a bit depth. I stopped trying after giving it a 19-digit exponent and a bit depth of 2¹²⁰.

I asked myself why would he make the limits so high. The only answer I could come up with is that there would be no need to modify it again. There is a bit of sense in that.

18-trillion GHz-Days in what's available now. I can believe that.

[ET_]

Originally Posted by storm5510

There used to be a member here named Luigi, a.k.a. E.T. Back in 2007, he wrote a little program called Factor5. It is not used much now. I tried to find a ceiling for what it would accept as an exponent and a bit depth. I stopped trying after giving it a 19-digit exponent and a bit depth of 2¹²⁰.

I asked myself why would he make the limits so high. The only answer I could come up with is that there would be no need to modify it again. There is a bit of sense in that.

18-trillion GHz-Days in what's available now. I can believe that.

The only limit for Factor5 is the sky... and your RAM. Using mpz_t elementys slows down the calculation, but keeps the app updated with Moore's law. And it's already suitable to sieve the 16 residual classes mod 60 in parallel. So, you can make ypur exponent (and your factor size) grow as long as you have memory to allocate

[storm5510]

Originally Posted by ET_

The only limit for Factor5 is the sky... and your RAM. Using mpz_t elementys slows down the calculation, but keeps the app updated with Moore's law. And it's already suitable to sieve the 16 residual classes mod 60 in parallel. So, you can make ypur exponent (and your factor size) grow as long as you have memory to allocate

Thank you for the reply.

It can really work a CPU, depending on what you give it. It sends the temperature on my i7-7700 into the mid 70's on the C scale when running hard.

Question: Why does it say "banned" just below your user name?

[ET_]

Originally Posted by storm5510

Thank you for the reply.

It can really work a CPU, depending on what you give it. It sends the temperature on my i7-7700 into the mid 70's on the C scale when running hard.

Question: Why does it say "banned" just below your user name?

Oh! I'not sure either I guess it is a comment of the super-supermod once I was whining too much on a past thread...

[nofaith628]

Haven't been here in a while, need your help regarding issues with CUDA driver compatibility.

Recently swapped a 1080TI with a TITAN V, getting

ERROR: cudaGetLastError() returned 8: invalid device function

Output from mfaktc-win-64.exe is as follows:

Compiletime options
  THREADS_PER_BLOCK         256
  SIEVE_SIZE_LIMIT          32kiB
  SIEVE_SIZE                193154bits
  SIEVE_SPLIT               250
  MORE_CLASSES              enabled

Runtime options
  SievePrimes               25000
  SievePrimesAdjust         1
  SievePrimesMin            5000
  SievePrimesMax            100000
  NumStreams                3
  CPUStreams                3
  GridSize                  3
  GPU Sieving               enabled
  GPUSievePrimes            82486
  GPUSieveSize              64Mi bits
  GPUSieveProcessSize       16Ki bits
  Checkpoints               enabled
  CheckpointDelay           30s
  WorkFileAddDelay          600s
  Stages                    enabled
  StopAfterFactor           bitlevel
  PrintMode                 full
  V5UserID                  (none)
  ComputerID                (none)
  AllowSleep                no
  TimeStampInResults        no

CUDA version info
  binary compiled for CUDA  8.0
  CUDA runtime version      8.0
  CUDA driver version       9.20

CUDA device info
  name                      TITAN V
  compute capability        7.0
  max threads per block     1024
  max shared memory per MP  98304 byte
  number of multiprocessors 80
  clock rate (CUDA cores)   1455MHz
  memory clock rate:        850MHz
  memory bus width:         3072 bit

Automatic parameters
  threads per grid          655360
  GPUSievePrimes (adjusted) 82486
  GPUsieve minimum exponent 1055144

running a simple selftest...
ERROR: cudaGetLastError() returned 8: invalid device function

Tried:
- Clean install of both Display Driver and CUDA
- CUDA 8.0 GA1
- CUDA 8.0 GA2

Still displaying CUDA driver version 9.20. Unable to match CUDA driver version with 8.0 despite efforts to reinstall driver.

Any help is appreciated!

[storm5510]

Originally Posted by nofaith628

running a simple selftest...
ERROR: cudaGetLastError() returned 8: invalid device function

- Clean install of both Display Driver and CUDA
- CUDA 8.0 GA1
- CUDA 8.0 GA2

Still displaying CUDA driver version 9.20. Unable to match CUDA driver version with 8.0 despite efforts to reinstall driver.

Any help is appreciated!

Are you getting any unexpected system restarts?

mfaktc displays the same, 8.0, 8.0, 9.20 for my 1080 and it runs fine.

[nofaith628]

Originally Posted by storm5510

Are you getting any unexpected system restarts?

mfaktc displays the same, 8.0, 8.0, 9.20 for my 1080 and it runs fine.

No unexpected system restarts as far I have ran mfaktc on this system. Switched the graphics card back to the 1080TI, running smoothly as always. Switching the card to a TITAN V, the error pops up.

On an another machine, mfaktc displays 8.0, 8.0, 9.20 for 1080 and 1080TI, running smoothly without issues.

Clean uninstallations of the CUDA driver and the Display Driver with the help of Revo Uninstaller, along with several restarts, and blocking the internet to prevent auto updates, have failed. There must be some files left in the computer that was not deleted during the uninstalling process. The CUDA driver version still shows 9.20.

[kladner]

@nofaith628
I heartily endorse Revo Uninstaller, which I use. To check on other remnants, you might try jv16 Power Tools. https://www.macecraft.com/download/
I have used it even longer than Revo. It is good at unearthing lingering bits in the registry.

[kriesel]

Originally Posted by nofaith628

No unexpected system restarts as far I have ran mfaktc on this system. Switched the graphics card back to the 1080TI, running smoothly as always. Switching the card to a TITAN V, the error pops up.

On an another machine, mfaktc displays 8.0, 8.0, 9.20 for 1080 and 1080TI, running smoothly without issues.

Clean uninstallations of the CUDA driver and the Display Driver with the help of Revo Uninstaller, along with several restarts, and blocking the internet to prevent auto updates, have failed. There must be some files left in the computer that was not deleted during the uninstalling process. The CUDA driver version still shows 9.20.

Are you sure Windows isn't updating the driver again, perhaps from some local stored content? ("System restore" etc)

https://answers.microsoft.com/en-us/...2-20cd32f4b1e9

search disabling windows driver updates for other articles that may help