[Mpi3-rma] Updated Proposal 1
balaji at mcs.anl.gov
Wed Dec 8 00:32:29 CST 2010
On 12/08/2010 12:25 AM, Underwood, Keith D wrote:
>> (b) Do we know any network (except ones that emulate one-sided
>> communication over two-sided messaging) that provide strict
>> ordering? As far as I know, most networks only provide ordering
>> between PUTs (or atomic PUTs). Ordering between GETs is also not
>> provided, unless the user does a flush after each GET operation. Is
>> this only for convenience?
> This ordering mode is what happens for UPC relaxed mode, so,
> presumably, some networks have some rational way to support it. Not
> that I am claiming that supporting that is easy if the network uses
> end-to-end retransmits for reliability...
Agreed. In fact, I believe ARMCI's semantics are also similar -- PUT to
a location followed by a GET from the same location will return the same
value. And GET followed by a PUT does not corrupt the data being received.
Maybe someone familiar with ARMCI on the list can tell us how they
achieve this on any network? Is there an internal flush before/after
each GET operation?
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