November 2011 - mpi-forum - mailman3.cels.anl.gov

Re: [Mpi-forum] Jan MPI Forum meeting
by Bronis R. de Supinski 09 Nov '11

09 Nov '11

Rich: Re: > For those trying to make travel arrangements - I would expect that the > meeting will go long on Wed, at least until 3 pm. Working groups are > trying to finish as much as possible for the 3.0 standard, so the > calendar is filling up with plenary sessions. Will we still start at at 1PM on Monday? Bronis

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Jan MPI Forum meeting
by Graham, Richard L. 09 Nov '11

09 Nov '11

For those trying to make travel arrangements - I would expect that the meeting will go long on Wed, at least until 3 pm. Working groups are trying to finish as much as possible for the 3.0 standard, so the calendar is filling up with plenary sessions. Rich

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Re: [Mpi-forum] MPI_Comm_create_group Meeting
by James Dinan 08 Nov '11

08 Nov '11

Hi All, Notes from yesterday's meeting are attached. Please note that we are moving all future discussion of this ticket to the mpi3-coll mailing list. Best, ~Jim. In attendance: Adam Moody, David Goodell, Jim Dinan, Pavan Balaji, Fab Tiller, Bronis de Supinski, Jeff Hammond Item 1: Name of the routine. We decided to stick with MPI_Comm_create group as the best way of matching the MPI_CLASS_ACTION_SUBSET naming convention. Item 2: Tag versus color. We decided to use a tag, which is defined to be in a collective tag space that is distinct from the point-to-point tag space. The collective tag will follow all MPI tag semantics, however it will not conflict with any point-to-point tags (including MPI_ANY_TAG). This essentially exposes the expected implementation in the standard, providing more flexible semantics to the user. In addition, it allows an implementation to make more efficient use of the tag space by defining tag conflicts across tagged collective operations (currently only MPI_Intercomm_create and MPI_Comm_create_group, but we could define others in the future). In a separate ticket, we can update MPI_Intercomm_create to specify that its tag is also in the collective tag space. This will be backward compatible, but will make MPI_Intercomm_create considerably easier to use because its tags will no longer conflict with point-to-point operations. Tasks: * Jim will work on a revision of the text that follows the above semantics. * The group will reconvene after Thanksgiving to review new text. * The group will move discussion to the collectives mailing list. On 11/4/11 11:07 AM, James Dinan wrote: > Based on the doodle poll, it looks like Monday at 3pm CT will be the > best time to meet. We'll use the hybrid WG telecon bridge: > > Domestic dial number: 866-654-6744 > International dial number: 517-308-8226 > Passcode: 6086006 > > See you then, > ~Jim. > > On 11/1/11 2:33 PM, James Dinan wrote: >> Hi All, >> >> I would like to form a group to review the MPI_Comm_create_group() >> proposal (#286) for a formal reading at the next Forum meeting. If you >> are interested in joining the discussion, could you please fill in your >> availability for a one hour conference call next week: >> >> http://www.doodle.com/9tganzq2hqiqy7kt >> >> We have a couple issues to discuss: >> >> 1.) The name of the function: MPI_Comm_create_group, >> MPI_Group_comm_create, MPI_Comm_create_from_group, ... >> >> 2.) The tag argument: Should we use a tag or a "color" to establish a >> safe communication conduit on the parent communicator. As discussed at >> the Forum, using a tag could conflict with the use of MPI_ANY_TAG on the >> parent communicator. A color would avoid this issue, however it could >> complicate tag matching. >> >> 3.) Changes to the text. >> >> Thanks, >> ~Jim. >> >> PS- I've attached a copy of the current text with comments from the >> formal reading at the last Forum meeting (in Acrobat: Comments -> >> Comments View -> Show Comments List for the full list). >> >> >> _______________________________________________ >> mpi-forum mailing list >> mpi-forum(a)lists.mpi-forum.org >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum

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Re: [Mpi-forum] MPI_Comm_create_group Meeting
by James Dinan 07 Nov '11

07 Nov '11

Reminder: we're meeting now. ~Jim. On 11/4/11 11:07 AM, James Dinan wrote: > Based on the doodle poll, it looks like Monday at 3pm CT will be the > best time to meet. We'll use the hybrid WG telecon bridge: > > Domestic dial number: 866-654-6744 > International dial number: 517-308-8226 > Passcode: 6086006 > > See you then, > ~Jim. > > On 11/1/11 2:33 PM, James Dinan wrote: >> Hi All, >> >> I would like to form a group to review the MPI_Comm_create_group() >> proposal (#286) for a formal reading at the next Forum meeting. If you >> are interested in joining the discussion, could you please fill in your >> availability for a one hour conference call next week: >> >> http://www.doodle.com/9tganzq2hqiqy7kt >> >> We have a couple issues to discuss: >> >> 1.) The name of the function: MPI_Comm_create_group, >> MPI_Group_comm_create, MPI_Comm_create_from_group, ... >> >> 2.) The tag argument: Should we use a tag or a "color" to establish a >> safe communication conduit on the parent communicator. As discussed at >> the Forum, using a tag could conflict with the use of MPI_ANY_TAG on the >> parent communicator. A color would avoid this issue, however it could >> complicate tag matching. >> >> 3.) Changes to the text. >> >> Thanks, >> ~Jim. >> >> PS- I've attached a copy of the current text with comments from the >> formal reading at the last Forum meeting (in Acrobat: Comments -> >> Comments View -> Show Comments List for the full list). >> >> >> _______________________________________________ >> mpi-forum mailing list >> mpi-forum(a)lists.mpi-forum.org >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum

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Re: [Mpi-forum] MPI_Comm_create_group Meeting
by James Dinan 04 Nov '11

04 Nov '11

Based on the doodle poll, it looks like Monday at 3pm CT will be the best time to meet. We'll use the hybrid WG telecon bridge: Domestic dial number: 866-654-6744 International dial number: 517-308-8226 Passcode: 6086006 See you then, ~Jim. On 11/1/11 2:33 PM, James Dinan wrote: > Hi All, > > I would like to form a group to review the MPI_Comm_create_group() > proposal (#286) for a formal reading at the next Forum meeting. If you > are interested in joining the discussion, could you please fill in your > availability for a one hour conference call next week: > > http://www.doodle.com/9tganzq2hqiqy7kt > > We have a couple issues to discuss: > > 1.) The name of the function: MPI_Comm_create_group, > MPI_Group_comm_create, MPI_Comm_create_from_group, ... > > 2.) The tag argument: Should we use a tag or a "color" to establish a > safe communication conduit on the parent communicator. As discussed at > the Forum, using a tag could conflict with the use of MPI_ANY_TAG on the > parent communicator. A color would avoid this issue, however it could > complicate tag matching. > > 3.) Changes to the text. > > Thanks, > ~Jim. > > PS- I've attached a copy of the current text with comments from the > formal reading at the last Forum meeting (in Acrobat: Comments -> > Comments View -> Show Comments List for the full list). > > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum

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Re: [Mpi-forum] MPI Forum BoF at SC 2011
by Jeff Squyres 03 Nov '11

03 Nov '11

On Nov 3, 2011, at 11:33 AM, James Dinan wrote: > These are the questions I've been mulling over internally: > > 1. Are C++ users limited by the C bindings? > 2. Would C++ users benefit substantially from C++ bindings? > 3. Do these bindings need to be in the MPI standard? These are good and fair questions. > Almost all C++ users I talk to would use C++ bindings if they were good bindings and thorough. However, this doesn't imply a strong "yes" to any of the above. One thing to clarify here: the MPI C++ bindings *are* thorough. Specifically: C++ bindings exist for every MPI-2.2 function. But keep in mind: they are *bindings*, meaning that it was an explicit goal of the Forum to make them [nearly] 1:1 to the C bindings. This is not what (some? most?) MPI C++ developers want, however. Making a good MPI C++ class library -- something with higher-level semantics over simple bindings -- is what I have heard most C++ developers ask for. The Forum specifically (and rightfully, IMNSHO) decided that such a class library was outside the scope of the standard. The fairly obvious argument is: once you go outside of a 1:1 mapping to the C bindings, you're -- by definition -- creating new semantics above and beyond what is proscribed in the MPI standard. Which seems like an excellent opportunity for a 3rd party library -- not the standard. > I think it would be really helpful to gather details on the technical shortcomings of C bindings in C++ code (the discussion on exceptions has been really interesting) and examples where a good C++ binding would have solved a development problem or provided a more elegant solution. The original intent of the C++ bindings was that they would provide a good bootstrapping for more "interesting" C++ MPI functionality. Unfortunately, that didn't really pan out. Case in point is that Boost.mpi is written with the C bindings, not the C++ bindings. I believe the existing C++ users who used the C++ bindings did so because they do offer a few C++-friendly abstractions (e.g., objects), making the MPI C++ bindings fit in well with the rest of their C++ code base. In a technical sense, it wouldn't be a tragedy to replace them with C bindings because, by definition, they are a nearly 1:1 mapping to the C bindings. But it does cost money and people and time to do that work. -- Jeff Squyres jsquyres(a)cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/

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Re: [Mpi-forum] MPI Forum BoF at SC 2011
by James Dinan 03 Nov '11

03 Nov '11

Hi Rich, These are the questions I've been mulling over internally: 1. Are C++ users limited by the C bindings? 2. Would C++ users benefit substantially from C++ bindings? 3. Do these bindings need to be in the MPI standard? Almost all C++ users I talk to would use C++ bindings if they were good bindings and thorough. However, this doesn't imply a strong "yes" to any of the above. I think it would be really helpful to gather details on the technical shortcomings of C bindings in C++ code (the discussion on exceptions has been really interesting) and examples where a good C++ binding would have solved a development problem or provided a more elegant solution. Cheers, ~Jim. On 11/3/11 9:42 AM, Graham, Richard L. wrote: > We can do this. > > With respect to C++, I would urge all to contact as many users as possible to see what their response is. I have already done with with respect to ORNL and LANL, and am planning on using the BoF for this. > > I do plan to do the same for all/most of the items on the list. > > Rich > > On Nov 3, 2011, at 10:31 AM, Torsten Hoefler wrote: > >> Great! Thanks for organizing this. >> >> It may be a good idea to have some straw votes with the audience. Just >> as a reality-check if the Forum's opinion reflects the general public. >> >> One particularly interesting topic would be a "public opinion" on >> the proposed handling of the C++ bindings. I hear some large push-back >> to deprecation (yes, it takes them a while to realize what we did) from >> the applications community which is clearly underrepresented at the >> Forum. >> >> Thanks& Best, >> Torsten >> >> -- >> bash$ :(){ :|:&};: --------------------- hxxp://www.unixer.de/ ----- >> Torsten Hoefler | Performance Modeling and Simulation Lead >> Blue Waters Directorate | University of Illinois (UIUC) >> 1205 W Clark Street | Urbana, IL, 61801 >> NCSA Building | +01 (217) 244-7736 >> _______________________________________________ >> mpi-forum mailing list >> mpi-forum(a)lists.mpi-forum.org >> hxxp://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum >> > > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum

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Re: [Mpi-forum] MPI Forum BoF at SC 2011
by Graham, Richard L. 03 Nov '11

03 Nov '11

We can do this. With respect to C++, I would urge all to contact as many users as possible to see what their response is. I have already done with with respect to ORNL and LANL, and am planning on using the BoF for this. I do plan to do the same for all/most of the items on the list. Rich On Nov 3, 2011, at 10:31 AM, Torsten Hoefler wrote: > Great! Thanks for organizing this. > > It may be a good idea to have some straw votes with the audience. Just > as a reality-check if the Forum's opinion reflects the general public. > > One particularly interesting topic would be a "public opinion" on > the proposed handling of the C++ bindings. I hear some large push-back > to deprecation (yes, it takes them a while to realize what we did) from > the applications community which is clearly underrepresented at the > Forum. > > Thanks & Best, > Torsten > > -- > bash$ :(){ :|:&};: --------------------- hxxp://www.unixer.de/ ----- > Torsten Hoefler | Performance Modeling and Simulation Lead > Blue Waters Directorate | University of Illinois (UIUC) > 1205 W Clark Street | Urbana, IL, 61801 > NCSA Building | +01 (217) 244-7736 > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > hxxp://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum >

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Re: [Mpi-forum] MPI Forum BoF at SC 2011
by Torsten Hoefler 03 Nov '11

03 Nov '11

Great! Thanks for organizing this. It may be a good idea to have some straw votes with the audience. Just as a reality-check if the Forum's opinion reflects the general public. One particularly interesting topic would be a "public opinion" on the proposed handling of the C++ bindings. I hear some large push-back to deprecation (yes, it takes them a while to realize what we did) from the applications community which is clearly underrepresented at the Forum. Thanks & Best, Torsten -- bash$ :(){ :|:&};: --------------------- http://www.unixer.de/ ----- Torsten Hoefler | Performance Modeling and Simulation Lead Blue Waters Directorate | University of Illinois (UIUC) 1205 W Clark Street | Urbana, IL, 61801 NCSA Building | +01 (217) 244-7736

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MPI Forum BoF at SC 2011
by Graham, Richard L. 02 Nov '11

02 Nov '11

The MPI Forum BoF at SC will be held on Wed, 11/16/2011, 5:30 - 7:00 pm, in romm TCC 301/302. The focus of this BoF will be the MPI 3.0 standard. All are invited to attend. Rich

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