[PATCH] D92419: [Support] On Windows, take the affinity mask into account

[Alexandre Ganea via Phabricator via llvm-commits]

aganea created this revision.
aganea added reviewers: hans, mehdi_amini, MaskRay, amccarth.
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aganea requested review of this revision.

Now using the affinity mask when it's set, thus limiting the number of processors available to the ThreadPool.
For example:

  > start /B /AFFINITY 0xF lld-link.exe ...

Would let LLD only use 4 hyper-threads.

This also fixes an issue on a 48-core Windows Server 2019, which was preventing from using both CPU sockets. In that case, `ProcessorGroup::AllThreads` was retrieved as 64 for each group, but `ProcessorGroup::UsableThreads` was set to 48 (which is the max possible for each group). The previous code in `llvm/lib/Support/Windows/Threading.inc` L201 was improperly assuming those values would be equal when the affinity mask was fully set. I've tested the new code on a wide variety of configurations & OSes (Windows Server 2016, 2019 and Windows 10).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92419

Files:
  llvm/include/llvm/Support/Program.h
  llvm/lib/Support/Program.cpp
  llvm/lib/Support/Unix/Program.inc
  llvm/lib/Support/Windows/Program.inc
  llvm/lib/Support/Windows/Threading.inc
  llvm/unittests/Support/ThreadPool.cpp

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