Stockfish is Broken in Windows 11 on some CPU's

Posts : 880 Join date : 2020-11-25 Location : USA

"This change is required to spread threads on all cores on Windows 11 with
a 3990X CPU. It has only 1 NUMA node with 2 groups of 64 threads each."

Stockfish is now broken in Window 11 on some of my testing computers due to the above patch. The computers with more then 16 threads to be exact.

Stockfish is Broken in Windows 11 on some CPU's Sf_bro10

I also tested this as shown above on my 8 Core 16 thread computer. And the NPS and Depth were all within 1% of each other.

So due to this patch Stockfish went from 22,009,133 nps to 13,075,761 nps and a depth of 42.4 plies to 39.6 plies at a 1m+1s time control.

Code:: Result:
--------------------------------------------------------------------------------
  # name games wins draws losses score elo + -
  1. Stockfish 11/11/21 21 0 21 0 10.5 1 49 49
  2. Stockfish 15/11/21 21 0 21 0 10.5 -1 49 49

Cross table:
--------------------------------------------------------------------------------
  # name score games 1 2
  1. Stockfish 11/11/21 10.5 21 x =====================-------------------------------------------------------------------------------
  2. Stockfish 15/11/21 10.5 21 =====================------------------------------------------------------------------------------- x

Tech:
--------------------------------------------------------------------------------

Tech (average nodes, depths, time/m per move, others per game), counted for computing moves only, ignored moves with zero nodes:
  # name nodes/m NPS depth/m time/m moves time
  1. Stockfish 11/11/21 41432K 22009133 42.4 1.9 58.1 109.4
  2. Stockfish 15/11/21 24838K 13075761 39.6 1.9 58.1 110.4
   all --- 32355K 17520516 41.0 1.9 58.1 109.9

Code:: Author: noobpwnftw
Date: Mon Nov 15 18:19:53 2021 +0100
Timestamp: 1636996793

Fix processor group binding under Windows.

Starting with Windows Build 20348 the behavior of the numa API has been changed:
https://docs.microsoft.com/en-us/windows/win32/procthread/numa-support

Old code only worked because there was probably a limit on how many
cores/threads can reside within one NUMA node, and the OS creates extra NUMA
nodes when necessary, however the actual mechanism of core binding is
done by "Processor Groups"(https://docs.microsoft.com/en-us/windows/win32/procthread/processor-groups). With a newer OS, one NUMA node can have many
such "Processor Groups" and we should just consistently use the number
of groups to bind the threads instead of deriving the topology from
the number of NUMA nodes.

This change is required to spread threads on all cores on Windows 11 with
a 3990X CPU. It has only 1 NUMA node with 2 groups of 64 threads each.

closes https://github.com/official-stockfish/Stockfish/pull/3787

No functional change.

Use windows 10

Posts : 880 Join date : 2020-11-25 Location : USA

Mclane wrote:: Use windows 10

You can not go backwards. All my systems are Windows 11. SF will just be tested at 16 threads until the issue is fixed.

Thats why i never change a running system and do not update the OS

Posts : 880 Join date : 2020-11-25 Location : USA

Mclane wrote:: Thats why i never change a running system and do not update the OS

This has nothing to due with the OS. This is a Stockfish issue. As all other Stockfish before the patch work just fine. Along with all the other chess engines.

Posts : 2901 Join date : 2020-11-18

mwyoung wrote:: "This change is required to spread threads on all cores on Windows 11 with
a 3990X CPU. It has only 1 NUMA node with 2 groups of 64 threads each."

Stockfish is now broken in Window 11 on some of my testing computers due to the above patch. The computers with more then 16 threads to be exact.

Here's the actual change (brownish red code deleted, green code added in its place) - link.

If you have a Github account, you can sign in and comment on the change.

You can also comment on the pull request - link. That pull request also has a test tab: you can put a failed test on that page.

Posts : 880 Join date : 2020-11-25 Location : USA

Stockfish has correct the issue with today's update. Very Happy

Author: noobpwnftw
Date: Mon Nov 22 13:31:13 2021 +0100
Timestamp: 1637584273

Revert and fix earlier windows NUMA patch

revert https://github.com/official-stockfish/Stockfish/commit/9048ac00db12a9ac48bff9b9eb145b30ff88d984 due to core spread problem and fix new OS compatibility with another method.

This code assumes that if one NUMA node has more than one processor groups, they are created equal(having equal amount of cores assigned to each of the groups), and also the total number of available cores contained in such groups are equal to the number of available cores within one NUMA node because of how best_node function works.

closes https://github.com/official-stockfish/Stockfish/pull/3798
fixes https://github.com/official-stockfish/Stockfish/pull/3787

Posts : 2901 Join date : 2020-11-18

That's good news!

It also demonstrates a benefit of having a widely used piece of software with a good community updating it.

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