[Mpi3-hybridpm] External interfaces chapter updates

Pavan Balaji balaji at mcs.anl.gov
Mon Nov 8 09:47:24 CST 2010


That part has been removed from the proposal as per the discussion two 
Forums back. I had accidentally added it in one of the intermediate drafts.

  -- Pavan

On 11/08/2010 08:55 AM, Douglas Miller wrote:
> Bronis,
>
>  >> >> Page 12 lines 46-48, I think MPI_THREAD_FUNNELED should have the
> same note
>  >> >> about excepting helper threads calls? I think it can still be
> allowed, or
>  >> >> might be desirable, to use helper threads in this case?
>  >>
>  >> I do not understand this comment. Which note? This confusion
>  >> is probably an issue over which version of Pavan's document
>  >> you used for page/line numbers. However, I think this comment
>  >> and all remaining ones only pertain to the version with more
>  >> significant changes (i.e., the helper threads and shared memory
>  >> proposals). I don't intend to integrate them into the branch
>  >> with the small changes yet so I will stop here. Please let
>  >> me know if I have misinterpreted something.
>
> I was referring to the note on MPI_THREAD_SERIALIZED that said that
> MPI_Helper_* calls were an exception to the rule that only one thread
> makes MPI calls at a time. I think (maybe) MPI_THREAD_FUNNELED should
> have the same/similar exception. We might have already discussed that,
> but I don't recall if there were compelling reasons to leave FUNNELED out.
>
>
> _______________________________________________
> Douglas Miller BlueGene Messaging Development
> IBM Corp., Rochester, MN USA Bldg 030-2 A410
> dougmill at us.ibm.com Douglas Miller/Rochester/IBM
>
> Inactive hide details for "Bronis R. de Supinski" ---11/05/2010 06:53:54
> PM---Pavan:"Bronis R. de Supinski" ---11/05/2010 06:53:54 PM---Pavan:
>
>       *"Bronis R. de Supinski" <bronis at llnl.gov>*
>       Sent by: mpi3-hybridpm-bounces at lists.mpi-forum.org
>
>       11/05/2010 06:52 PM
>       Please respond to
>       "Bronis R. de Supinski" <bronis at llnl.gov>; Please respond to
>       mpi3-hybridpm at lists.mpi-forum.org
>
> 	
>
> To
> 	
>
>       "mpi3-hybridpm at lists.mpi-forum.org"
>       <mpi3-hybridpm at lists.mpi-forum.org>
>
>
> cc
> 	
>
> Subject
> 	
>
>       Re: [Mpi3-hybridpm] External interfaces chapter updates
>
> 	
>
>
>
> Pavan:
>
> Sorry I had to drop out of the call early today but
> I had to be somewhere at noon.
>
> Anyway, I am looking over Doug's comments now.
>
> Pavan and Doug:
>
> Re:
>  > Pavan:
>  >
>  > Doug's first issue indicates that you need to update
>  > your PDF again. I have fixed that issue (which you
>  > caught earlier) in the current draft in the MPI-3.0
>  > trunk. Please start with the version that is now in
>  > the MPI-3.0-2010-11-draft branch as I have made the
>  > other minor corrections that we have discussed in
>  > that section.
>
> Looks good now. Thanks.
>
>  > I will look over Doug's other points to see which
>  > should be included in that draft as well as your
>  > proposed version once you update it.
>  >
>  > Thanks,
>  >
>  > Bronis
>  >
>  >
>  > On Mon, 1 Nov 2010, Douglas Miller wrote:
>  >
>  >> Just proof reading again...
>  >>
>  >> Page 11 lines 32-34, this paragraph still says "Advice to implementers"
>  >> twice.
>
> This issue should now be fixed in all versions.
>
>  >> Page 12 lines 3-4, missing close-paren at "async-signal-safe".
>
> Good catch. fixing it requires that we move the period outside
> of the quotation marks so it can follow the close-paren. I have
> made this change and commited it to MPI-3.0-2010-11-draft branch
> in which we are storing changes that will not go out in the
> first release draft since they have not been discussed/seen by
> the overall Forum (I know this seems like it should be OK to
> include in that draft but I am just following my understanding
> of the rules; it should get into the next release draft).
>
>  >> Page 12 lines 46-48, I think MPI_THREAD_FUNNELED should have the
> same note
>  >> about excepting helper threads calls? I think it can still be
> allowed, or
>  >> might be desirable, to use helper threads in this case?
>
> I do not understand this comment. Which note? This confusion
> is probably an issue over which version of Pavan's document
> you used for page/line numbers. However, I think this comment
> and all remaining ones only pertain to the version with more
> significant changes (i.e., the helper threads and shared memory
> proposals). I don't intend to integrate them into the branch
> with the small changes yet so I will stop here. Please let
> me know if I have misinterpreted something.
>
>
> Pavan:
>
> Where are you keeping the version with the more significant
> changes? Did you have Jeff cut you a branch? We should definitely
> do something to keep those working changes available. It would
> probably be good if both of us had write access to them in
> case something happens and you need someone else to pick it up.
>
> Bronis
>
>
>
>
>  >> Page 14 lines 42.5-48, the wording sounds a little soft, as if the only
>  >> goal is to pass the linking phase. should it additionally say something
>  >> like "must return a meaningful and accurate value"?
>  >>
>  >> Pages 16-17, should we add an "advice to users" to recommend/remind
> that
>  >> all communications between JOIN and LEAVE be self-completing? What I
> mean
>  >> is that if a thread does an MPI_ISEND between JOIN and LEAVE, that
> is also
>  >> does an MPI_WAIT (or equiv.) on that ISEND before LEAVE? Since JOIN and
>  >> LEAVE have no knowledge of requests, etc, isn't that prudent or even
>  >> necessary?
>  >>
>  >> Page 17, section 12.5 Shared Memory. Rather than be collective,
> could these
>  >> calls reflect the API of something like shm_open() whereby they have a
>  >> "key" parameter that uniquely identifies the segment of shared
> memory? Our
>  >> experience with DCMF (where we did all shmem allocations in a ordered,
>  >> synchronized "collective" manner) was that it is fraught with
> problems and
>  >> restrictions. We're moving to using an API that takes a string "key" so
>  >> that we need not force such semantics. Are there any OS shmem APIs that
>  >> require ordered, collective allocation? I know UPC does not use a
> "key",
>  >> but wouldn't this allow for better implementations? Are there platforms
>  >> where these semantics would NOT work? [probably a topic for our meeting]
>  >>
>  >> [also another topic for the meeting] Should we say something about
> how to
>  >> get a communicator of appropriate ranks for shmem allocation? Many
>  >> platforms do not support global shared memory (only shmem local to a
> node),
>  >> and I don't think there are any MPI mechanisms for testing or selecting
>  >> ranks that are node-local.
>  >>
>  >> Thanks, Pavan, for doing this integration, by the way.
>  >> Myself, I don't know LaTeX and can't afford the learning curve right
> now,
>  >> so you're really helping out.
>  >>
>  >> _______________________________________________
>  >> Douglas Miller BlueGene Messaging Development
>  >> IBM Corp., Rochester, MN USA Bldg 030-2 A410
>  >> dougmill at us.ibm.com Douglas Miller/Rochester/IBM
>  >>
>  >> [cid:1__=09BBFD5DDFD0140C8f9e8a93df938 at us.ibm.com]Pavan Balaji
>  >> ---10/30/2010 07:37:24 PM---On 10/30/2010 01:49 PM, Bronis R. de
> Supinski
>  >> wrote:
>  >>
>  >>
>  >> Pavan Balaji <balaji at mcs.anl.gov>
>  >> Sent by: mpi3-hybridpm-bounces at lists.mpi-forum.org
>  >>
>  >> 10/30/2010 07:36 PM
>  >> Please respond to
>  >> mpi3-hybridpm at lists.mpi-forum.org
>  >>
>  >>
>  >>
>  >>
>  >> To
>  >>
>  >> "Bronis R. de Supinski" <bronis at llnl.gov>,
>  >> mpi3-hybridpm at lists.mpi-forum.org
>  >>
>  >> cc
>  >>
>  >>
>  >>
>  >> Subject
>  >>
>  >> Re: [Mpi3-hybridpm] External interfaces chapter updates
>  >>
>  >>
>  >>
>  >>
>  >> On 10/30/2010 01:49 PM, Bronis R. de Supinski wrote:
>  >>>> I think it's time for us to start dumping in text into the chapter and
>  >>>> start discussing the exact wording. I've included the helper
> threads and
>  >>>> shared memory extensions proposals into the chapter and uploaded it to
>  >>>> the wiki
>  >>>>
> (https://svn.mpi-forum.org/trac/mpi-forum-web/attachment/wiki/MPI3Hybrid/ei-2-v0.1.pdf).
>  >>>> Please take a look at it and let me know your comments.
>  >>>
>  >>> I'll try to make a detailed reading next week. In the
>  >>
>  >> I had initially incorrectly uploaded a change with respect to the
>  >> MPI_THREAD_SERIALIZED semantics which we decided to drop last time. I've
>  >> now uploaded v0.2 of the document with this correction as well as the
>  >> other changes suggested by Bronis.
>  >>
>  >> -- Pavan
>  >>
>  >> --
>  >> Pavan Balaji
>  >> http://www.mcs.anl.gov/~balaji
>  >> _______________________________________________
>  >> Mpi3-hybridpm mailing list
>  >> Mpi3-hybridpm at lists.mpi-forum.org
>  >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-hybridpm
>  >>
>  >>
>  >
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-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji



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