[mpiwg-rma] [EXTERNAL] Re: Synchronization on shared memory windows

[Jeff Hammond]

On Wed, Feb 5, 2014 at 11:57 AM, Balaji, Pavan <balaji at anl.gov> wrote:
>
> On Feb 5, 2014, at 11:54 AM, Jeff Hammond <jeff.science at gmail.com> wrote:
>> I think advice to users regarding WIN_SYNC wouldn't hurt given that
>> some of us are talking about it as if it is a portable abstraction for
>> a memory barrier when it is now only correct to use it within an RMA
>> sync epoch.  Or we need to relax this restriction.
>
> Without this restriction, there’s no connection to what memory is being made consistent with the WIN_SYNC call.  I’d be against removing it.

The memory being made consistent is obviously the public and private
window.  In the case of UNIFIED, it's just a memory barrier.  Right?

I suppose someone could always WIN_LOCK+WIN_SYNC+WIN_UNLOCK as a
portable abstraction for a memory barrier in the case where an epoch
is not already established.

Jeff


-- 
Jeff Hammond
jeff.science at gmail.com