Prime95 30.8 (big P-1 changes, see post #551)

[mathwiz]

The thread title says "small exponents only". Apologies if I've missed this elsewhere in the thread but what is considered "small" if we want to beta test 30.8 with some P-1 work?

[lycorn]

Originally Posted by techn1ciaN

IIUC, recent versions of Windows (10 and 11 are the ones I have relevant experience with) will start opportunistically caching system files if there is not much RAM being "actively" used. This is not associated with any particular program, so wouldn't show up in Task Manager.

That makes a whole lot of sense, and it´s probably happening in my system (I´m using Win10).

Originally Posted by techn1ciaN

Windows's caching creeps in during stage 1, but the necessary space is always vacated when stage 2 starts.

Well, that would be the sensible thing to do, no doubt about it. Yet I am not really sure that it´s actually working that way. When stage 2 starts, the TM quickly indicates 96% to 97% (!) of mem usage, even though P95 is claiming to use no more than the 12 GB I had allocated, and the rest of the tasks appearing in the TM window are using at most 1 GB all together. There still appears to be something behind the scenes stealing resources (RAM, in this case). The memory usage tends to later stabilize at around 93-94% but there is still a "missing" amount of memory of approximately 2 GB.

[Uncwilly]

Originally Posted by mathwiz

The thread title says "small exponents only". Apologies if I've missed this elsewhere in the thread but what is considered "small" if we want to beta test 30.8 with some P-1 work?

Try numbers below 100M. This is specifically useful for those working below the DC milestone of 58M and even more so for those trying to find factors for exponents below 20M.

Originally Posted by Prime95

Should you wish to try 30.8, same warnings as before. Links are below.

• P-1 stage 2 is untested on 100M+ exponents. I am not sure the code can accurately gauge when the new code is faster than the old code.

[lisanderke]

14923 I received 2888 GHzDs P-1 credit for this workload while it took me probably less than an hr to complete, perhaps credit given should be recalculated after a full release of 30.8 or higher versions!


Mind you, B2 was a whopping ~1,142,499 times B1!

Sending result to server: UID: lisander/30.8b2, M14923 completed P-1, B1=100000000, B2=114249978542700, Wi4: EB22----

PrimeNet success code with additional info:
CPU credit is 2888.2833 GHz-days.

[techn1ciaN]

Originally Posted by lycorn

Yet I am not really sure that it´s actually working that way. When stage 2 starts, the TM quickly indicates 96% to 97% (!) of mem usage, even though P95 is claiming to use no more than the 12 GB I had allocated, and the rest of the tasks appearing in the TM window are using at most 1 GB all together. There still appears to be something behind the scenes stealing resources (RAM, in this case). The memory usage tends to later stabilize at around 93-94% but there is still a "missing" amount of memory of approximately 2 GB.

Windows does not tend to give up the spare space it parks unless you make it. Going back to my laptop, we know that I can give Prime95 13 GB of RAM (and possibly more) without problems, but Task Manager still reports "90%" system RAM usage during stage 2 even if I allocate just 9 or 10 GB. Windows will only clear out just enough of its cache to meet foreground programs' RAM requests, and usually not more.

You might try starting something else that you know uses at least a couple GB of RAM (e.g., a web browser) while Prime95 is in stage 2 and then checking Task Manager. You should find that the usage of the remaining 4 GB in your system becomes more "visible."

[petrw1]

Originally Posted by Prime95

[*]AVX-512 is untested -- likely to fail (perhaps silently). Pre-AVX is untested but might work. Recommend using only AVX and FMA FFTs.

Yup .... silently.
Per Att. #1.
Right after this Prime95 just went away....no other message.

Per Att. #2
This was on my i7-7820x

How do I force it to use AVX/FMA FFTs?

[axn]

From undoc.txt

The program supports many different code paths for PRP/LL testing depending on
the CPU type.  It also has a few different factoring code paths.  You can
force the program to choose a specific code path by setting the proper
combination of these settings in local.txt:
	CpuSupportsRDTSC=0 or 1
	CpuSupportsCMOV=0 or 1
	CpuSupportsPrefetch=0 or 1
	CpuSupportsSSE=0 or 1
	CpuSupportsSSE2=0 or 1
	CpuSupports3DNow=0 or 1
	CpuSupportsAVX=0 or 1
	CpuSupportsFMA3=0 or 1
	CpuSupportsFMA4=0 or 1
	CpuSupportsAVX2=0 or 1
	CpuSupportsAVX512F=0 or 1

Just setting the last option to 0 should cause it to fallback to next best thing (i.e. FMA)

[axn]

Originally Posted by Prime95

I suspect restarting build 2 will multithread just fine (until it doesn't).

This is repeatable. Multiple restarts with build 2 all yielded same behavior - top shows consistently at 200% instead of the expected high 500%

[petrw1]

Originally Posted by axn

From undoc.txt

The program supports many different code paths for PRP/LL testing depending on
the CPU type.  It also has a few different factoring code paths.  You can
force the program to choose a specific code path by setting the proper
combination of these settings in local.txt:
	
	CpuSupportsAVX512F=0 or 1

Just setting the last option to 0 should cause it to fallback to next best thing (i.e. FMA)

[Prime95]

Originally Posted by axn

This is repeatable. Multiple restarts with build 2 all yielded same behavior - top shows consistently at 200% instead of the expected high 500%

Can you send the usual files: worktodo.txt, prime.txt, local.txt, save file.

Thanks.

[axn]

Originally Posted by Prime95

Can you send the usual files: worktodo.txt, prime.txt, local.txt, save file.

Thanks.

https://www.mediafire.com/file/cm4ds...files.zip/file

Contains two save files. The save files were created by 30.7 with 8M/400M bounds. I am extending B2 to 2G with 30.8