8343249: [Windows] Implement SpinPause #21781
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SpinPause is currently not implemented on any Windows platforms, due to a lack of access to assembly in the Microsoft compiler. The YieldProcessor macro can act as a stand in for this purpose, as it compiles down to a single pause instruction on x64 (Which seems to be all that one needs to implement SpinPause in HotSpot). I am less certain about the Windows/ARM64 implementation. There, YieldProcessor compiles down to dmb ishst; yield and I am unsure whether that is a correct SpinPause implementation. If need be, I can retract the ARM64 implementation and only have this for x86
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$ git fetch https://git.openjdk.org/jdk.git pull/21781/head:pull/21781
$ git checkout pull/21781
Update a local copy of the PR:
$ git checkout pull/21781
$ git pull https://git.openjdk.org/jdk.git pull/21781/head
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$ git pr checkout 21781
View PR using the GUI difftool:
$ git pr show -t 21781
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https://git.openjdk.org/jdk/pull/21781.diff
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