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

[pepi37]

I have problem I cannot solve ( not big ones, but still)
An all my Linux boxes SMT is off in the BIOS, but regardless that fact all Linux boxes has 2 x mprime threds then cores.
For example in picture below it is Ryzen 5 3600 , with SMT off. It has 6 threads of mprime running at 100% and 6 instances running on 0%. How to fix it?
https://www.dropbox.com/s/47mrdhzm6m...rime.jpg?RAW=1

[paulunderwood]

Originally Posted by pepi37

I have problem I cannot solve ( not big ones, but still)
An all my Linux boxes SMT is off in the BIOS, but regardless that fact all Linux boxes has 2 x mprime threds then cores.
For example in picture below it is Ryzen 5 3600 , with SMT off. It has 6 threads of mprime running at 100% and 6 instances running on 0%. How to fix it?
https://www.dropbox.com/s/47mrdhzm6m...rime.jpg?RAW=1

The Ryzen 3600 is a 6 core machine. Prime95/mprime is so well written in assembler that SMT/HT (hyperthreading) is practically useless. Run only 6 instances.

Why are you not running SMT?

[James Heinrich]

Originally Posted by pepi37

How to fix it?

mprime -m > 2. Test/Workers > Number of workers to run = 6 > CPU cores to use (multithreading) = 1

Or in local.txt (edit while mprime isn't running)
WorkerThreads=6
CoresPerTest=1

(or, if you prefer, some other combination that multiplies to 6)

[kruoli]

Please make sure Stage2ExtraThreads=0 is in prime.txt.

[pepi37]

Originally Posted by paulunderwood

The Ryzen 3600 is a 6 core machine. Prime95/mprime is so well written in assembler that SMT/HT (hyperthreading) is practically useless. Run only 6 instances.

Why are you not running SMT?

First you say SMT is useless then you ask why I dont run SMT?

[pepi37]

Originally Posted by James Heinrich

mprime -m > 2. Test/Workers > Number of workers to run = 6 > CPU cores to use (multithreading) = 1

Or in local.txt (edit while mprime isn't running)
WorkerThreads=6
CoresPerTest=1

(or, if you prefer, some other combination that multiplies to 6)

Thanks, I sense that is answer 🥳

[paulunderwood]

Originally Posted by pepi37

First you say SMT is useless then you ask why I dont run SMT?

The answer might have been "to reduce electricity costs". HT/SMT uses more juice.

[pepi37]

Originally Posted by paulunderwood

The answer might have been "to save electricity", HT/SMT uses more juice.

Answer is it is useless, and I know CPU is cooler with SMT off, so that is reason why I wrote that fact in my first post

[paulunderwood]

Originally Posted by pepi37

Answer is it is useless, and I know CPU is cooler with SMT off, so that is reason why I wrote that fact in my first post

Oh, okay. I did not read all, if any, of your original post. TL;DR thread. All the best!

[pepi37]

Originally Posted by James Heinrich

mprime -m > 2. Test/Workers > Number of workers to run = 6 > CPU cores to use (multithreading) = 1

Or in local.txt (edit while mprime isn't running)
WorkerThreads=6
CoresPerTest=1

(or, if you prefer, some other combination that multiplies to 6)

This wasnot help, since

WorkerThreads=6
CoresPerTest=1
was already in local.txt, and running mprime menu didnot solve problem

[pepi37]

Originally Posted by kruoli

Please make sure Stage2ExtraThreads=0 is in prime.txt.

That is I assume ( not sure) for P-1, not for PRP


It looks like it is way that HTOP show different ( more process) then TOP.

So it looks like all is ok, and SMT is off ...like BIOS say :)