discuss about release barrier for final fields initialization

[Wei Kuai]

I've submitted a jbs for it. https://bugs.openjdk.org/browse/JDK-8324186

Thanks,
Kuai Wei

On Fri, Jan 19, 2024 at 5:08 PM Andrew Haley <aph-open at littlepinkcloud.com>
wrote:

> On 1/18/24 10:49, Wei Kuai wrote:
> >    I tested "dmb.ishst; dmb.ishld" for release barrier. The test case is
> jmh of allocation with final fields.
> https://gist.github.com/kuaiwei/f71fba40df29991c93325a8600e34c13 <
> https://gist.github.com/kuaiwei/f71fba40df29991c93325a8600e34c13>
> > In N1
> >    dmb.ish                    : 1168.059 ops/s
> >    dmb.ishst+dmb.ishld: 1321.783 ops/s
> >    dmb.ishst                 : 1511.267 ops/s
> > In N2
> >    dmb.ish                    : 3672.087 ops/s
> >    dmb.ishst+dmb.ishld: 4840.322 ops/s
> >    dmb.ishst                 : 6005.430 ops/s
> >
> > The "dmb.ishst+dmb.ishld" can gain 13% and 32% on N1 and N2. It looks a
> better replacement for "dmb.ish"
>
> Let's do that, then.
>
> If you'd like to submit a patch that does this, please make sure to include
> the benchmark.
>
> We should also stop merging 'dmb ld' and 'dmb st' into 'dmb sy'. We still
> want
> to merge duplicated `dmb`s, but the side effect of strengthening is not
> good.
>
> --
> Andrew Haley  (he/him)
> Java Platform Lead Engineer
> Red Hat UK Ltd. <https://www.redhat.com>
> https://keybase.io/andrewhaley
> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
>
>
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