RFR: jsr166 jdk9 integration wave 9

Martin Buchholz martinrb at google.com
Thu Aug 11 22:59:16 UTC 2016

On Thu, Aug 11, 2016 at 2:12 PM, Aleksey Shipilev <
aleksey.shipilev at gmail.com> wrote:

> On 08/11/2016 11:56 PM, Martin Buchholz wrote:
> > I can imagine a machine that has a native cas instruction, but no native
> > exchange instruction, but no one ever got fired for optimizing for x86.
> ...which would be less of an issue once we switch to proper-boolean
> VarHandles, not the int-simulation. This way, implementations may choose
> how to implement boolean getAndSet. Probably in Unsafe, but that would
> still be lower and more reusable than in AtomicBoolean alone.

I like the current int simulation, at least for AtomicBoolean.  You'll
never save space by switching to boolean, because of alignment, and you
don't have to worry about machines without byte-sized instructions.  But
like I always say, "no one ever got fired for optimizing for x86"!

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