RFR: 8359435: AArch64: add support for 8.5 SB instruction
Andrew Haley
aph at openjdk.org
Fri Jun 13 14:24:27 UTC 2025
On Fri, 13 Jun 2025 14:00:08 GMT, Evgeny Astigeevich <eastigeevich at openjdk.org> wrote:
> Speculation Barrier (SB) instruction can be used instead of a pair of DSB, ISB if supported. It should have better performance than DSB+ISB (https://developer.arm.com/documentation/102825/0100):
>
>> ... a DSB+ISB sequence is expected to have a significantly greater impact on performance than an SB ...
>
> CPUs supporting it:
> - Apple M2+
> - Neoverse-N2
> - Neoverse-V2
>
> Tested:
> - Gtests passed
I think this can wait until we have a use for `SB`.
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PR Comment: https://git.openjdk.org/jdk/pull/25801#issuecomment-2970563338
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