What exactly shared means?

[John Colvin via Digitalmars-d-learn]

On Friday, 2 January 2015 at 23:56:44 UTC, Ola Fosheim Grøstad 
wrote:
> On Friday, 2 January 2015 at 23:10:46 UTC, John Colvin wrote:
>> What significant optimisations does SC-DRF actually prevent?
>
> By "SC-DRF" I assume you mean the Java memory model.

The Java, C11 and C++11 memory model.

> AFAIK SCDRF just means that if you syncronize correctly 
> (manually) then you will get sequential consistency 
> (restriction on the compiler).

That sounds like a correct description of it to me, yes.

> Getting rid of the restrictions on the compiler and eliding 
> programmer-provided syncronization allows for more 
> optimizations on loads, writes, reordering, 
> syncronization/refcounting...?

Yes, I was hoping that perhaps you knew more specifics. AFAIK, 
when not restricted by any kind of barriers, SC-DRF does not have 
a particularly significant cost.