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A comment on LLVM Clang 12 Merges Support For x86_64 Microarchitecture Levels. Parent comment

Re:LLVM Clang 12 Merges Support For x86_64 Microarchitecture... by jcranmer on Sunday November 08, 2020 @04:04PM (#25029027)
> they lacking TSX or SGX.

Note that the SGX instructions are system only, so the compiler isn't generating them usually. The hardware lock elision instructions in TSX are specifically chosen so that they act as NOPs on processors that don't support TSX.

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Re:LLVM Clang 12 Merges Support For x86_64 Microarchitecture... by my123 on Sunday November 08, 2020 @04:35PM (#25029296)
Hardware lock elision was disabled via a microcode update. (see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...)
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Re:LLVM Clang 12 Merges Support For x86_64 Microarchitecture... by throwaway2048 on Sunday November 08, 2020 @08:44PM (#25030659)
Not to mention TSX instructions have been broken in one way or another since their introduction, and now have been removed entirely in new intel silicon.
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