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Subject: Re: [OMPI devel] Preparations for moving the btl's
From: Ralph Castain (rhc_at_[hidden])
Date: 2008-12-03 15:02:29

I managed to execute the modex-less changes pretty much without
introducing additional ORTE dependencies into the BTL's, though there
may be some additions as we look a the other BTLs that I didn't
address. So hopefully that won't contribute too much to the issue here.

At the moment, I don't think it matters where notifier sits - it might
be able to move to OPAL. Only catch will be if some notifier component
requires communications. I'm thinking of FTB, for example, and our own
local monitoring program that may require TCP messaging. We don't
currently have anything in OPAL that would support an OPAL level
messaging system, though perhaps that could be resolved.

We also have dependencies where the BTL's will call orte_ess to find
out what node another proc is on, the node local rank of that proc,
etc. Those dependencies are likely to grow after the Dec meeting (see
wiki for that agenda item), and definitely cannot be moved to OPAL.

However, note that Rich stated the BTL's were -not- moving to OPAL.
This begs the question: where -are- they going? Into their own layer?
Will that layer be somewhere in-between OMPI and ORTE (in which case,
the ORTE dependencies are moot)?

I note that the wiki page doesn't address any of these questions,
which is understandable if things are just getting underway. But it
does sound like this is going to take some thought to ensure we don't
paint ourselves into a corner.


On Dec 3, 2008, at 12:10 PM, Jeff Squyres wrote:

> FWIW, I see lots of notifier calls being added to the BTLs (and
> elsewhere throughout the OMPI code base) over time...
> On Dec 3, 2008, at 2:07 PM, Tim Mattox wrote:
>> The BTLs might have added calls to the notifier framework in their
>> error paths.
>> The notifier framework is currently in the ORTE layer... not sure
>> if we could
>> move it down to OPAL. Ralph, any thoughts on that?
>> On Wed, Dec 3, 2008 at 11:56 AM, Richard Graham <rlgraham_at_[hidden]>
>> wrote:
>>> George told me about what he is doing, so no changes would be
>>> committed
>>> until George has his changes in.
>>> Are there other changes to the btl's that we should be aware of ?
>>> Rich
>>> On 12/3/08 11:47 AM, "George Bosilca" <bosilca_at_[hidden]> wrote:
>>>> Terry,
>>>> I'm involved [at some degree] in both efforts and I can confirm
>>>> these
>>>> two efforts will not affect each other in any bad way.
>>>> george.
>>>> On Dec 3, 2008, at 11:42 , Terry Dontje wrote:
>>>>> I don't have any *strong* objections. However, I know that Eugene
>>>>> and George B have been working on some Fastpath code changes
>>>>> that we
>>>>> should make sure neither project obliterates the other.
>>>>> --td
>>>>> Richard Graham wrote:
>>>>>> Now that 1.3 will be released, we would like to go ahead with the
>>>>>> plan to move the btl¹s out of the MPI layer. Greg Koenig who is
>>>>>> doing most of the work has started a wiki page with details on
>>>>>> the
>>>>>> plans. Right now details are sketchy, as Greg is digging through
>>>>>> the code, and has only hand written notes on data structures that
>>>>>> need to be moved, include files that are not needed, etc. The
>>>>>> page
>>>>>> is at:
>>>>>> _
>>>>>> The first three steps basically only involve code motion, moving
>>>>>> items such as ompi_list, and renaming them, moving where the code
>>>>>> is actually located in the repository, and the like. For these we
>>>>>> do not plan to put out a formal RFC, but comments are very
>>>>>> welcome,
>>>>>> and any hands that are willing to help with this are even more
>>>>>> welcome.
>>>>>> The last phase where the btl¹s are made dependent on OPAL, and
>>>>>> supporting libraries such as mpools I expect will be disruptive,
>>>>>> and will definitely require an RFC, and will also be a longer
>>>>>> process.
>>>>>> Please send comments,
>>>>>> Rich
>>>>>> ------------------------------------------------------------------------
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>> --
>> Tim Mattox, Ph.D. -
>> tmattox_at_[hidden] || timattox_at_[hidden]
>> I'm a bright...
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> --
> Jeff Squyres
> Cisco Systems
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