Re: [Qemu-devel] Java volatile vs. C11 seq_cst (was Re: [PATCH v2 1/2] add a header file for atomic operations)

[Andrew Haley]

On 06/19/2013 10:30 AM, Paolo Bonzini wrote:
> Il 18/06/2013 19:38, Andrew Haley ha scritto:
>>>> Or is Java volatile somewhere between acq_rel and seq_cst, as the last
>>>> paragraph of
>>>> http://www.cs.umd.edu/~pugh/java/memoryModel/jsr-133-faq.html#volatile
>>>> seems to suggest?
>> As far as I know, the Java semantics are acq/rel.  I can't see anything
>> there that suggests otherwise.  If we'd wanted to know for certain we
>> should have CC'd Doug lea.
> 
> acq/rel wouldn't have a full store-load barrier between a volatile store
> and a volatile load.

Ahhh, okay.  I had to check the C++11 spec to see the difference.  I'm
so deep into the Java world that I hadn't noticed that C++11 was any
different.

Andrew.