RFR 8068977 Remove unused sun.misc.Unsafe prefetch intrinsic support

[Vladimir Kozlov]

Hi Paul,

These are JIT compilers changes so I added correct mailing list.
Changes look fine to me. Make sure it passed JPRT.

RFE:
https://bugs.openjdk.java.net/browse/JDK-8068977

"Note read/write prefetch support was implemented as an experiment to see if JDK library code could use it for 
performance advantages. However, the results of the experiment did not indicate this was worthwhile."

Also note, there are no corresponding prefetch native methods declaration in sun.misc.Unsafe. We had it sometime in 
local sources for experiments but we never pushed those changes into main s.m.Unsafe sources.

Thanks,
Vladimir

On 2/5/15 4:07 AM, Paul Sandoz wrote:
> Hi.
>
> Please review this patch to remove prefetch read/write support:
>
> http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8068977-hotspot-prefetch-intrinsic-cleanup/webrev/
>
> This is covering a lot of areas and i could of easily fat fingered something and/or in my ignorance made a mistake, so please check carefully.
>
> There is a corresponding patch for closed source that i will send internally.
>
> Paul.
>