RFR: 8295069: [PPC64] Performance regression after JDK-8290025 [v2]

[Andrew Haley]

On Mon, 10 Oct 2022 20:58:33 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> > Might it make sense for PPC to do what AArch64 does? We don't need any memory fence instructions on the fast path.
> 
> We are actually doing what AArch64 does, now. AArch64 still uses `membar(__ LoadLoad)` for (non-generational) ZGC and ShenandoahGC, because they use `NMethodPatchingType::conc_data_patch`. Other GCs don't need any memory fence instructions. 

Ah, okay. On AArch64 we only issue a `LoadLoad` for `conc_data_patch` so I think we're good.

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PR: https://git.openjdk.org/jdk/pull/10632