Engines Fail to use all cores in Intel scalable Platinum cpu

[Sharaf_DG]

My system has 2 intel 8180 processors with 112 logical cores. I was unable to set all cores to run Stockfish, and their derivatives, nor am I able to set affinity to run Non HT cores. Took the issue up with intel as well as the pc vendor, and after their investigation this what they had to say ...

"Processor affinity is dynamically handled by the OS in win10. The only way an application will have access to all of those cores (in Group0 and Group1) is if it is specifically written to support such a thing. Windows is basically handling all of the processor affinity settings dynamically, and from what I understand it assigns applications in alternating order to Group0/1 to try to balance load.

So if you're looking at how much CPU that specific application is utilizing, it will appear capped at 50% because Windows has assigned it to a single group (likely because the application is not written in such a way that it's able to take advantage of spanning groups)."

[Dann Corbit]

My system has 2 intel 8180 processors with 112 logical cores. I was unable to set all cores to run Stockfish, and their derivatives, nor am I able to set affinity to run Non HT cores. Took the issue up with intel as well as the pc vendor, and after their investigation this what they had to say ...

"Processor affinity is dynamically handled by the OS in win10. The only way an application will have access to all of those cores (in Group0 and Group1) is if it is specifically written to support such a thing. Windows is basically handling all of the processor affinity settings dynamically, and from what I understand it assigns applications in alternating order to Group0/1 to try to balance load.

So if you're looking at how much CPU that specific application is utilizing, it will appear capped at 50% because Windows has assigned it to a single group (likely because the application is not written in such a way that it's able to take advantage of spanning groups)."

It is not unlikely that you are simply hitting the compile limit for the core count.

There are special NUMA builds of SF that should use all your cores.
Recent versions of SF use a vector that grows as big as you need it.

See here for stockfish tests up to 192 threads:
http://www.ipmanchess.yolasite.com/test ... hreads.php
And here is a list that shows tests up to 384 threads:
http://www.ipmanchess.yolasite.com/amd- ... -bench.php

So 224 threads should be a piece of cake.

They even have tests with your CPU (and at 4x rather than 2x).

I guess that this is what you must change:
cluster-on-die ->Off
From the notes on Ipman's page.

[Sharaf_DG]

I don't find cluster on die in my bios. Any idea how to disable cluster on die

thank you

[Dann Corbit]

I don't find cluster on die in my bios. Any idea how to disable cluster on die

thank you

I do not have that architecture so I cannot say for sure.

This link says it is a bios option:
http://en.community.dell.com/techcenter ... ll-servers

[Nordlandia]

Ahmed Mansoor: do you accept FEN request for analysis?