[mpi3-rma] Plans ?

[Shipman, Galen M.]

One semantic that I have used before is to allow the implementation  
to return an ordering tag (optional) after a request is submitted  
(say for a PUT).
This ordering tag can then be used in subsequent operations to  
enforce ordering w.r.t. the previous request. For some networks that  
provide ordering on a per connection basis, the ordering tag can  
simply map to a particular connection. If the implementation does not  
support ordering for a specific (or any) request then it can return a  
special "no order" tag.  Not saying this is a good thing, just have  
used it before.

- Galen


On Jan 27, 2008, at 8:13 PM, Pavan Balaji wrote:

>
> Oh, and I forgot to add that the RMA operations themselves should
> probably be allowed to set a "fence" flag as well, which would be
> equivalent to RMA operation + 0-byte send with special tag set.  
> That is,
> they would be flushed out immediately, but will not require any
> interference from the remote process.
>
>   -- Pavan
>
> On 01/27/2008 07:08 PM, Pavan Balaji wrote:
>> Rich, Jarek,
>>
>> The ordering should definitely not be enforced in all cases. As I
>> mentioned in the brief description below, the application should  
>> be able
>> to inform the MPI stack to flush out previous requests through a
>> "special tag". Consider an example where the sender wants to place  
>> some
>> data in the receiver buffers through RMA operations and inform it  
>> that
>> the data is written through a regular send operation -- this can be
>> achieved by tagging the last send with the special tag, instead of
>> having the receiver wait for the window to be closed before being  
>> able
>> to use the data received through RMA operations. This is similar to
>> fence, but on a process-pair basis, rather than on a window basis.
>>
>>  -- Pavan
>>
>> On 01/27/2008 06:50 PM, Nieplocha, Jarek wrote:
>>> Good point Rich.
>>> Enforcing ordering for all the cases say on networks with adaptive
>>> routing can be expensive and unnecessary.
>>>
>>> Jarek
>>>
>>> ________________________________
>>>
>>> From: mpi3-rma-bounces at cs.uiuc.edu on behalf of Richard Graham
>>> Sent: Sun 1/27/2008 4:44 PM
>>> To: MPI 3 Remote Memory Operations
>>> Subject: Re: [mpi3-rma] Plans ?
>>>
>>>
>>> Can you elaborate on this ?
>>>
>>> What is the intent ?
>>>
>>> Do you want to have ordering be required, or optional ?  Seems like
>>> there are times
>>>  where you would like to have ordering guarantees, and others in  
>>> which
>>> you want the
>>>  network to blast things through as fast a possible, w/o concern for
>>> ordering.
>>>
>>> Rich
>>>
>>>
>>> On 1/27/08 12:26 AM, "Pavan Balaji" <balaji at mcs.anl.gov> wrote:
>>>
>>>
>>>
>>>
>>>
>>>     I was planning to write a proposal on ordering and completion of
>>>     requests. Specifically, to treat RMA operations as ordered with
>>> respect
>>>     to how application writers perceive it. That is, if process A
>>> sends an
>>>     RMA message to process B, and then sends a regular message to
>>> process B
>>>     (with a special TAG, for instance), the MPI stack on process  
>>> B should
>>>     deliver both the RMA message as well as the regular message  
>>> to the
>>>     application. That is, it should not wait for the remote  
>>> window to
>>> close
>>>     before doing so.
>>>
>>>     However, it'll be good to have a telecon to bounce off ideas  
>>> and get
>>>     initial comments before we go off and spend time writing more
>>> detailed
>>>     proposals.
>>>
>>>     Is a telecon being planned? I don't seem to have received any  
>>> email
>>>     about this.
>>>
>>>       -- Pavan
>>>
>>>     On 01/26/2008 10:43 PM, Rajeev Thakur wrote:
>>>> It would be good to know if anyone is planning to write a
>>> proposal on any
>>>> topic for MPI-3 RMA.
>>>>
>>>> Rajeev
>>>>
>>>>> -----Original Message-----
>>>>> From: mpi3-rma-bounces at cs.uiuc.edu
>>>>> [mailto:mpi3-rma-bounces at cs.uiuc.edu] On Behalf Of Richard Graham
>>>>> Sent: Wednesday, January 23, 2008 10:18 AM
>>>>> To: mpi3-rma at cs.uiuc.edu
>>>>> Subject: [mpi3-rma] Plans ?
>>>>>
>>>>> What are the plans for this working group ?  At the meeting
>>>>> last week there seemed to be quite a bit of interest in this
>>>>> topic, and it seemed like there could be at least 2 groups
>>>>> working on this.  Seems like, if this is the case, it would
>>>>> be better to try and coordinate early on within the working
>>>>> group, rather than try and rationalize two or more well
>>>>> developed proposals.
>>>>> Any thoughts here ?
>>>>>
>>>>> Rich
>>>>>
>>>>> _______________________________________________
>>>>> mpi3-rma mailing list
>>>>> mpi3-rma at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/mpi3-rma
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> mpi3-rma mailing list
>>>> mpi3-rma at cs.uiuc.edu
>>>> http://lists.cs.uiuc.edu/mailman/listinfo/mpi3-rma
>>>>
>>>
>>>     --
>>>     Pavan Balaji
>>>     http://www.mcs.anl.gov/~balaji
>>>     _______________________________________________
>>>     mpi3-rma mailing list
>>>     mpi3-rma at cs.uiuc.edu
>>>     http://lists.cs.uiuc.edu/mailman/listinfo/mpi3-rma
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> mpi3-rma mailing list
>>> mpi3-rma at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/mpi3-rma
>>>
>>
>
> -- 
> Pavan Balaji
> http://www.mcs.anl.gov/~balaji
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> mpi3-rma mailing list
> mpi3-rma at cs.uiuc.edu
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