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Subject: Re: [OMPI devel] [EXTERNAL] Re: RTE Framework
From: Richard Graham (richardg_at_[hidden])
Date: 2013-01-24 11:19:10


So 3 units of modularity at this stage - got it.

Thanks,
Rich

-----Original Message-----
From: devel-bounces_at_[hidden] [mailto:devel-bounces_at_[hidden]] On Behalf Of Barrett, Brian W
Sent: Wednesday, January 23, 2013 5:26 PM
To: Open MPI Developers
Subject: Re: [OMPI devel] [EXTERNAL] Re: RTE Framework

That's not entirely true; there's some state that's required to be held by the RTE framework (the ompi_process_info structure), but it's minimal and does not scale with number of peers in a job.

In terms of interface, there's now three MPI frameworks which encompass the set of functionality the MPI layer needs: rte, pubsub, and dpm (the last two are the dynamic process stuff). The RTE framework is a fairly small set of functions, probably 20? I'm hoping we can shrink it slightly over time, but it's going to require some thought and changes to the OMPI layer, so I didn't want to do it all in one go.

Brian

On 1/23/13 8:03 AM, "Ralph Castain" <rhc_at_[hidden]> wrote:

>I'm not entirely sure what you're asking here. There is no state at all
>in the MPI layer - just a set of function calls. Each component in the
>ompi/mca/rte framework is required to map those function calls to their
>own implementation. The function calls themselves are just a rename of
>the current ORTE calls, so the implementations must provide the same
>functionality - they are simply free to do so however they choose.
>
>
>On Jan 22, 2013, at 11:31 PM, Richard Graham <richardg_at_[hidden]>
>wrote:
>
>> Brian,
>> First - thanks. I am very happy this is proceeding.
>> General question here - do you have any idea how much global state
>>sits behind the current implementation ? What I am trying to gauge at
>>what level of granularity one can bring in additional capabilities.
>> I have not looked in detail yet, but will in the near future.
>>
>> Thanks,
>> Rich
>>
>> -----Original Message-----
>> From: devel-bounces_at_[hidden] [mailto:devel-bounces_at_[hidden]]
>>On Behalf Of Barrett, Brian W
>> Sent: Monday, January 21, 2013 9:31 PM
>> To: Open MPI Developers
>> Subject: [OMPI devel] RFC: RTE Framework
>>
>> Hi all -
>>
>> As discussed at the December developer's meeting, a number of us have
>>been working on a framework in OMPI to encompass the RTE resources
>>(typically provided by ORTE). This follows on work Oak Ridge did on
>>the ORCA layer, which ended up having a number of technical challenges
>>and was dropped for a simpler approach.
>>
>> The interface is still a work in process and designed around the
>>concept that the ORTE component is a thin renaming around ORTE itself
>>(this was one of the points the ORTE developers felt strongly about).
>>We think it's ready for comments and coming into the trunk, so are
>>trying to get it looked at by a broader community. The Mercurial
>>repository is available
>> at:
>>
>> https://bitbucket.org/rhc/ompi-trunk
>>
>> This work is focussed only on the creation of a framework to
>>encompass the RTE interface between OMPI and ORTE. There are
>>currently two
>>components:
>> the ORTE component and a test component implemented over PMI. The
>>PMI component is only really useful if ORTE is disabled at autogen
>>time with the --no-orte option to autogen. Future work to build
>>against an external OMPI (in progress, on a different branch) will
>>make using non-orte components slightly more useful.
>>
>> Anyway, if there aren't any major comments, I'll plan on bringing
>>this work to the trunk this weekend (Jan 26/27).
>>
>> Brian
>>
>> --
>> Brian W. Barrett
>> Scalable System Software Group
>> Sandia National Laboratories
>>
>>
>>
>>
>> _______________________________________________
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>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
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--
  Brian W. Barrett
  Scalable System Software Group
  Sandia National Laboratories