Prime95 v30.3

[Prime95]

Originally Posted by ixfd64

I noticed that the latest version still uses the older "Wh4" identifier in the results.txt file. Is this intentional?

The Wh4 code is not really used anymore. Over time it loosely relates to gwnum FFT library version number. The middle letter gets bumped when there are major changes to the FFT code.

[ZFR]

What's the best way of upgrading from 29.8 to 30.3 of mprime on Linux, so as not to lose existing work? Just unpack everything into mprime, and overwrite any existing files?

[Prime95]

Originally Posted by ZFR

What's the best way of upgrading from 29.8 to 30.3 of mprime on Linux, so as not to lose existing work? Just unpack everything into mprime, and overwrite any existing files?

That should work. Make a backup if you're leery (or prudent).

[ZFR]

Originally Posted by Prime95

That should work. Make a backup if you're leery (or prudent).

Thank you, Sir. Looks like everything went well.

[ZFR]

Actually, I'm getting this when I select 2. Test / Worker Threads

Number of workers to run (4): 

Options for worker #1

Type of work to get (0): 
CPU cores to use (multithreading): 2

Options for worker #2

Type of work to get (0): 
CPU cores to use (multithreading): 2

Options for worker #3

Type of work to get (0): 
CPU cores to use (multithreading): 2

Options for worker #4

Type of work to get (0): 
CPU cores to use (multithreading): 2
Get occasional proof certification work (Y): 

Accept the answers above? (Y): 
You have allocated more cores than are available.  This is likely to
GREATLY REDUCE performance.  Do you want to correct this? (Y):

My CPU should have 2 threads per 4 cores

Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
CPU speed: 4000.04 MHz, 4 hyperthreaded cores
CPU features: Prefetch, SSE, SSE2, SSE4, AVX, AVX2, FMA
L1 cache size: 4x32 KB, L2 cache size: 4x256 KB, L3 cache size: 8 MB

[ZFR]

I'm getting the "You have allocated more cores than are available." message even when I run 29.8 that I've backed up. So it looks like it's not a v30.3 issue. Still, I wonder why I get this. I'm pretty sure I haven't come across this message when I first set up mprime.

[James Heinrich]

Prime95 has explicit GUI settings that show that hyperthreading is specifically not-recommended (except in the case of TF which itself is not-recommended). Just allocate 4 workers with 1 core per worker. 2 hyperthreads per worker may actually produce less throughput than a single worker per real core.

[jwnutter]

Originally Posted by James Heinrich

Prime95 has explicit GUI settings that show that hyperthreading is specifically not-recommended (except in the case of TF which itself is not-recommended). Just allocate 4 workers with 1 core per worker. 2 hyperthreads per worker may actually produce less throughput than a single worker per real core.

@ZFR - Here's an example from a recent ~24 hour benchmark I completed on a i9-9900KF. That said, there are many other benchmarks in this same thread and you might consider benchmarking your system assuming you haven't already.

https://www.mersenneforum.org/showpo...&postcount=821

[ZFR]

I'm using mprime, so no GUI... But I've moved this from Prime95 when I switched from Windows to Linux. I must have missed the warning because as far as I remember I've been using 4 worker threads ever since I got this PC 5 years ago...

So what's the best way to change this to 1 worker without losing any progress. Can I just change to 1 worker in Settings in the menu and then manually change the worktodo file?

[James Heinrich]

You can still keep 4 workers, that's not a problem. Just use one thread per worker, not 2.

Number of workers to run (4):
CPU cores to use (multithreading): 2
CPU cores to use (multithreading): 1

[ZFR]

Originally Posted by James Heinrich

You can still keep 4 workers, that's not a problem. Just use one thread per worker, not 2.

OK, I see.

When I run the the mprime menu "2. Test/Worker threads" it doesn't give me the option to use 1 thread per worker. I only get to choose "Number of Workers to run" and if I choose 4, then for "CPU cores to use (multithreading)": 2 gets selected automatically.