Prime95 version 29.6/29.7/29.8

[Prime95]

Originally Posted by Random

I can confirm the error. 8700K CPU on win10 x64 1903. Tested in a clean VM as well and received the same error.

My bad, included the 32-bit hwloc-15.dll.

I repaired and uploaded the win64 zip file

[Random]

Originally Posted by Prime95

My bad, included the 32-bit hwloc-15.dll.

I repaired and uploaded the win64 zip file

The app starts normally now, thanks a lot for all your work.

[Prime95]

Originally Posted by nomead

And on Zen 2, what FFT is supposed to be used, FMA3 or AVX2? For some reason, the program selects FMA3 (FFT length 2688K). On the 2200G, I could force AVX2 through options in local.txt, but of course, it ran slower than FMA3, as expected.

All Ryzen CPUs should use FMA3 FFTs for maximum speed.

On the 3600, it gives this error, when trying to continue from a savefile:

[Work thread Aug 19 14:37] Cannot initialize FFT code, errcode=1002
[Work thread Aug 19 14:37] Number sent to gwsetup is too large for the FFTs to handle.

Hmm. Does the worktodo.txt entry specify a specific FFT size? If so, remove it. Otherwise, PM me the savefile and worktodo.txt entry that is failing.

[ixfd64]

Originally Posted by GP2

Chrome will soon be dropping support for the FTP protocol, starting with version 82. It's currently at version 76.

Can we change the links in the first post to:
https://www.mersenne.org/ftp_root/gimps/p95v298b6.linux64.tar.gz
and so forth?

That will have the added benefit of being more secure than downloading executables over an unencrypted connection.

Somewhat related issue: the directory at https://mersenne.org/ftp_root/gimps gives a 403 error. This makes it hard to download older versions of software.

[hansl]

Originally Posted by Prime95

The process is to launch 24 threads, init them all, then wait for all to complete initialization, then do the 5 seconds of counting iterations. I hope the increased run time is for doing 24 initializations vs. just one initialization. I'll add an option to print a message that all workers have finished initialization so that you can see if the wall clock time for the single worker and 24 worker cases are both about 5 seconds once initialization completes.

Originally Posted by Prime95

In 29.8 build 6 add "BenchInitCompleteMessage=1" to prime.txt.

So just to follow up: I now confirm that after initialization, the actual benchmarking seems to be constant 5s as configured. Thanks again.

[Madpoo]

Originally Posted by ixfd64

Somewhat related issue: the directory at https://mersenne.org/ftp_root/gimps gives a 403 error. This makes it hard to download older versions of software.

Although that web page does just point to the same spot as the FTP files, I haven't enabled directory browsing for it (separate option for web pages).

I think it'd be safe to do that since it's the same as the FTP site. I'll double-check... it's hard to overcome the knee-jerk reaction to NEVER enable directory browsing on a web page.

When I was first testing out ftp vs http for the file downloads, HTTP was beating FTP, in terms of speed, by a pretty good amount. Which seemed counter intuitive to me at first. I set the download page accordingly, to prefer http over ftp when it was picking which mirror to use (right now there really aren't any up to date mirrors, so the only one you'll get is http at Primenet anyway).

I think someone recently pointed out that although the rest of the site forces HTTPS, the downloads are still HTTP. It didn't make much sense to me to bother encrypting the zip files in transit. If someone's worried about a MITM when downloading, they can compare the hashes we put on the download page, which is HTTPS.

(I know that's all way more info than you asked about, but I like to throw a little "fun fact" stuff out there, just in case more questions come up)

[Madpoo]

Originally Posted by Madpoo

Although that web page does just point to the same spot as the FTP files, I haven't enabled directory browsing for it (separate option for web pages).

I think it'd be safe to do that since it's the same as the FTP site. I'll double-check... it's hard to overcome the knee-jerk reaction to NEVER enable directory browsing on a web page.

Done... file listing enabled:
http://www.mersenne.org/ftp_root/gimps/

[nomead]

Originally Posted by Prime95

All Ryzen CPUs should use FMA3 FFTs for maximum speed.

Okay, good to know that it's supposed to do that even on Zen 2.

Originally Posted by Prime95

Hmm. Does the worktodo.txt entry specify a specific FFT size? If so, remove it. Otherwise, PM me the savefile and worktodo.txt entry that is failing.

DoubleCheck=(AID censored),49683839,74,1 for example.
And apparently it doesn't even require a savefile to get that error. It does that if I try to force it to use AVX2 or even AVx (by setting CpuSupportsFMA3=0 and then CpuSupportsAVX=1 in local.txt). Used to work on the Ryzen 3 2200G, but as mentioned, it was slower than FMA3.

But anyway, if it's supposed to use FMA3 anyway, I'll be happy with that information.

[hansl]

What sort of operations does mprime use libgmp for? From grepping the docs I only found a mention to Jacobi error checking, is that the only thing?

I ask because I recently built a dev version of libgmp which has some Zen architecture optimizations(znver1) and it seemed to speed up a particular PARI/GP script for me by maybe 2x. I can't tell what version is bundled with mprime, because apparently all version of libgmp.so are just labeled 10.3.2 for some reason, even thought current stable is 6.1.2.

[Prime95]

Originally Posted by hansl

What sort of operations does mprime use libgmp for? From grepping the docs I only found a mention to Jacobi error checking, is that the only thing?

I ask because I recently built a dev version of libgmp which has some Zen architecture optimizations(znver1) and it seemed to speed up a particular PARI/GP script for me by maybe 2x. I can't tell what version is bundled with mprime, because apparently all version of libgmp.so are just labeled 10.3.2 for some reason, even thought current stable is 6.1.2.

Jacobi check and GCDs (P-1 and ECM). Mprime is bundled with 6.1.2.

[Evil Genius]

Originally Posted by Prime95

All Ryzen CPUs should use FMA3 FFTs for maximum speed.

Are you really sure? Zen 2 has double the AVX-256 bit speed compared to Zen 1. All data paths were widened for this purpose also. I was kinda hoping for an AVX-256 bit implementation for Zen 2.