mfakto: an OpenCL program for Mersenne prefactoring

[Dubslow]

Originally Posted by nucleon

i7-39xx - hex core +HT LGA2011 -- SANDY BRIDGE (32nm)
i7-38xx - quad core +HT LGA2011 -- SANDY BRIDGE (32nm)
i7-37xx - quad core +HT LGA1155 -- IVY BRIDGE (22nm)
i7-35xx - quad core no HT LGA1155 -- IVY BRIDGE (22nm)

LGA2011 - no inbuilt GPU
LGA1155 - on die GPU

It does have some sense to it.

-- Craig

Except for the whole different architectures thing. One architecture should be 2xxx, and the other 3xxx so we can tell the difference at a glance. It would be a lovely and excellent naming system, if the got the series/architecture part right. Do agree the rest is sensible.

[nucleon]

True - I was a bit surprised with SNB-E was i7-3xxx, I was expecting i7-2xxx.

They kinda of baked themselves into a corner with IVB-E (if it ever gets released)



-- Craig Meyers

[Dubslow]

Originally Posted by nucleon

True - I was a bit surprised with SNB-E was i7-3xxx, I was expecting i7-2xxx.

They kinda of baked themselves into a corner with IVB-E (if it ever gets released)



-- Craig Meyers

If they call it i7-4xxx I'll shoot something.

[Bdot]

Originally Posted by kracker

http://www.mersenneforum.org/showpos...&postcount=307
http://www.newegg.com/Product/Produc...82E16819103942

P.S.: Using 64k binary

Would you mind running a single assignment when the machine is otherwise idle and send

1. GPU model (including core speed if overclocked)
2. Assignment (e.g. "Factor=54321987,69,70")
3. Real time to run assignment
4. GPU usage in percent (average)

to James? So he can update the GPU performance page.

Actually, not just you. It would be good if everyone running the 0.11 version helps this page by submitting measurements ...

[kracker]

Originally Posted by Bdot

Would you mind running a single assignment when the machine is otherwise idle and send

1. GPU model (including core speed if overclocked)
2. Assignment (e.g. "Factor=54321987,69,70")
3. Real time to run assignment
4. GPU usage in percent (average)

to James? So he can update the GPU performance page.

Actually, not just you. It would be good if everyone running the 0.11 version helps this page by submitting measurements ...

Ok, I will, after this current batch finishes :)

[Bdot]

Originally Posted by dbaugh

I am using an i7-3960x with a Radeon HD 7970. mfakto compiles and passes both the self test and the two suggested test worktodo values. When I give it something that takes more that a couple of minutes, I lose my screen (all monitor timeouts are disabled). Sometimes it gives me a messed up screen first. I can only get it back by doing a power on reset. Is there a way to force the system (Win7) to use the onchip graphics and leave the video card for opencl work?

Thanks,

David

Finally someone testing mfakto on HD7970, Thanks!

I guess the onchip graphics question has been "solved" , I'll try and help with the current setup.

If all went well, there should be no need to switch to another card - your card should be able to handle it all. So if the kernels run for too long, then there's something wrong.

First test would be to lower GridSize in mfakto.ini and see if that improves the situation. Start with GridSize=0 and increase it as long as it is stable.

Second, I'd suggest to use GPU-Z or something similar to see if the card's core clock goes up when mfakto is running. It is hard to believe that this card could not handle a block of 2M candidates within the timeout.

Third, I'd like you to run the performance info version of mfakto (from here) like this:
mfakto-pi -st > perfinfo.txt
You can Ctrl-C it after a minute or so. Using this output I can determine which of the kernels potentially takes too long.

[dbaugh]

Installed 12-4 driver. Set ini to GridSize=0. Had GPU-Z.0.6.2 running. GPU Core Clock jumped from 300 to 950, GPU Memory Clock jumped from 150 to 1425 and GPU Load jumped from 0% to 68% when I start mfakto. The same blank screen after a couple of minutes or less. I have the CPU box on a wattmeter and it goes from 180 to 325 when I start mfakto. It drops to 220 when the screen blanks out. Indicating that the GPU is no longer working very hard. Tried to attach the perfinfo.txt file from start to a couple of minutes after blankout, but it is 5MB.

WBR,

David

[Bdot]

Originally Posted by dbaugh

Installed 12-4 driver. Set ini to GridSize=0. Had GPU-Z.0.6.2 running. GPU Core Clock jumped from 300 to 950, GPU Memory Clock jumped from 150 to 1425 and GPU Load jumped from 0% to 68% when I start mfakto. The same blank screen after a couple of minutes or less. I have the CPU box on a wattmeter and it goes from 180 to 325 when I start mfakto. It drops to 220 when the screen blanks out. Indicating that the GPU is no longer working very hard. Tried to attach the perfinfo.txt file from start to a couple of minutes after blankout, but it is 5MB.

WBR,

David

I've sent you a pm with an email address where you can forward the perfinfo.txt to.

Well, it seems I had misunderstood the problem a bit. I thought the test would run into the graphics driver timeout of Windows. But now I understand that testing some assignment starts OK, processes a few classes and then stops with screen garbage or blank screen. This would indeed indicate a hardware problem, maybe of the GPU fan(s). In GPU-Z, do you see very high temperatures for the GPU (above 80 or 90 C)? All fans running?

The AMD driver should also have installed "AMD VISION Engine Control Center". In there, under power or performance, there should be Graphics Overdrive - usually used for overclocking. But I'd like you to move the GPU and memory clock sliders to the lowest possible settings (probably around 600MHz for the GPU). And then test again. This setting should produce way less heat, and if that was the issue, then it should run stable (but slow) now.

If heat was the problem, then other GPU tests, like furmark, will also show the issue.

[kracker]

@bdot:
OT, but I just wanted to ask you, are "compute elements" stream processors or is it something different?

Thanks

...
maximum threads per block 256
maximum threads per grid 16777216
number of multiprocessors 5 (400 compute elements (estimate for ATI GPUs))
clock rate 600MHz
...

[Bdot]

Originally Posted by kracker

@bdot:
OT, but I just wanted to ask you, are "compute elements" stream processors or is it something different?

Thanks

...
maximum threads per block 256
maximum threads per grid 16777216
number of multiprocessors 5 (400 compute elements (estimate for ATI GPUs))
clock rate 600MHz
...

so far it is just 80 times the number of multiprocessors reported by the hardware. Unfortunately there is no reported number of stream processors, so I used the multiplier of the VLIW5 architecture. For VLIW4 (Cayman) this is already different, and for GCN (Tahiti) anyways. 400 is obviously not quite true for your card ...

And that is not offtopic. I wanted to automate this calculation long ago, but is is harder than I imagined. I'll try to come up with something for the next release.

Hmm, which card was that? The report you sent me for HD7970 contains

number of multiprocessors 32 (2560 compute elements (estimate for ATI GPUs))

Thanks for your perfinfo, btw. There's good and bad news.

The bad news is, that these results do not show any indication what might go wrong with your card - the tests advance normally and successfully as on any other card (which is actually good).

The good news is, that HD7970 can top HD6970 by at least 10% in mfakto. However, completely different way I thought. The 15-bit kernel that helped bring Cayman to the top is the absolutely slowest one on Tahiti. It appears that Tahiti no longer imposes a penalty on 32-bit operations because suddenly the plain 32-bit barrett79 kernel is the fastest with a theoretical throughput of 360M/s.

I guess with a little optimization for this platform 400 seems feasible. However, that stability issue is certainly alarming. Maybe you post that issue to http://devgurus.amd.com/community/opencl, there are amd folks and geeks who can better help troubleshoot.

[kracker]

Yeah, I believe mine has 600 stream processors on it

Edit: BTW, the 7970 has 2048.