RFR: 8322535: Change default AArch64 SpinPause instruction

Tue Jan 16 15:53:20 UTC 2024

On Tue, 16 Jan 2024 14:54:42 GMT, Andrew Haley <aph at openjdk.org> wrote:

> Your customers are running cloud apps on Apple M1/M2?

In theory they could. M1, M2 and M2 Pro instances are available in cloud. However I am not aware any such cases.

> Yeah, I know. What I don't know is how much of a cargo cult this is. Apple M1 etc. have very large reorder buffers, and serializing all instructions may not be the best plan.

I hope hardware engineers will notice this improper uses of ISB and will either implement YIELD or something equivalent  to it. YIELD could be an alias of a new instruction.

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PR Comment: https://git.openjdk.org/jdk/pull/17430#issuecomment-1894020670