gpuOwL: an OpenCL program for Mersenne primality testing

Originally Posted by GP2

You can find some PRPs that need DC from the following users:

Warning: not all are type 4. There's no way to filter by residue type, although you can click on the "Residue Type" column header to sort by it.

Also, I think gpuOwL only produces residues with shift count zero, so the double check will also have shift count zero, and some might insist that it's not a proper double check unless it's with a different shift count.

• Mihai Preda
• Kriesel
• kwe5ykdf
• tServo
• Franklin Webber
• Xebecer
• xx005fs
• SEL-ROC
• kracker

At this point gpuOwl is good for discovering new primes, the double-check should be done with a different program, maybe mprime with fast cpu and memory.

[LaurV]

[offtopic]
hehe, we love the new thread title, some supermods are really creative

[/offtopic]

Originally Posted by SELROC

It was with the wrong set of system software, not enough up to date, gpuowl started but after a while the residue was zeroed out, and a page fault occurred.


After installing the latest kernel, modules and headers, v. 5.0, then gpuowl works without problems and the zero-residue error is gone.

Originally Posted by SELROC

The same error has occurred again, zero-residue, but this time gpuowl reloaded the last checkpoint and continued.


I found that I was running a version of openowl compiled against old libs. Now I have recompiled and waiting to see if the error occurs again.

Originally Posted by SELROC

After some hour no error. Will see today the continuation.

The error occurred again today, after X days of work. Gpuowl has reloaded last checkpoint and is continuing.

[preda]

Originally Posted by SELROC

The error occurred again today, after X days of work. Gpuowl has reloaded last checkpoint and is continuing.

On what hardware -- is the hardware setup verified reliable?

What do you suspect as the reason for errors? (GPUowl, driver, hardware, something else)

Originally Posted by preda

On what hardware -- is the hardware setup verified reliable?

What do you suspect as the reason for errors? (GPUowl, driver, hardware, something else)

Gigabyte mainboard

radeon VII
Ubuntu
ROCm 2.2

kernel 5.0.5


the previous time I hit a page fault but not this time (after recompiling gpuowl)

[preda]

Originally Posted by SELROC

Gigabyte mainboard

radeon VII
Ubuntu
ROCm 2.2

kernel 5.0.5


the previous time I hit a page fault but not this time (after recompiling gpuowl)

Congrats on the R7! Did you undervolt/overclock? (if yes, that may explain the errors from time to time)

Originally Posted by preda

Congrats on the R7! Did you undervolt/overclock? (if yes, that may explain the errors from time to time)

PS: the setup has been validated against known prime.


the gpu is in automatic mode.

[preda]

Originally Posted by SELROC

PS: the setup has been validated against known prime.

the gpu is in automatic mode.

So you did not undervolt/overclock? (when you see the errors you report)

Originally Posted by preda

So you did not undervolt/overclock? (when you see the errors you report)

No.


the voltage is ~1.04 V


SCLK 1802 MHz
MCLK 1001 MHz

Originally Posted by preda

On what hardware -- is the hardware setup verified reliable?

What do you suspect as the reason for errors? (GPUowl, driver, hardware, something else)

No no, gpuowl on his part has done a very good job of reloading the checkpoint and continuing.


The error manifests with a zero residue, so it may be that gpuowl is sometimes reading from the wrong location, and this may correspond to a page fault.

Originally Posted by preda

On what hardware -- is the hardware setup verified reliable?

What do you suspect as the reason for errors? (GPUowl, driver, hardware, something else)

Originally Posted by SELROC

No no, gpuowl on his part has done a very good job of reloading the checkpoint and continuing.


The error manifests with a zero residue, so it may be that gpuowl is sometimes reading from the wrong location, and this may correspond to a page fault.

It may be my negligence, I was running kernel 5.0.5 but with an outdated initramfs. After updating initramfs the error is not occurring.