September 2025 - mpi-forum - mailman3.cels.anl.gov

MPI 5.0 Implementation Status
by Wes Bland 30 Sep '25

30 Sep '25

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Re: [Mpi-forum] Proposal process for a side document for C++ Language Interface for MPI-5.x
by Jeff Hammond 29 Sep '25

29 Sep '25

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Reading of Erratum issue for Appendix A.2
by Christoph Niethammer 16 Sep '25

16 Sep '25

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RMA WG Reading at September Meeting
by Joseph Schuchart 14 Sep '25

14 Sep '25

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Re: [Mpi-forum] Proposal process for a side document for C++ Language Interface for MPI-5.x
by Anthony Skjellum 12 Sep '25

12 Sep '25

Jeff and friends, A layered implementation on top of C adds no performance path for C++. Only a functional interface . It has to deal with all the limitations inherited from the C interface too. Tony Skjellum On Fri, Sep 12, 2025 at 1:46 PM Ghosh, Sayan via mpi-forum < mpi-forum(a)lists.mpi-forum.org> wrote: > Hi Jeff, From recent discussions in the C++/Languages WG, it was apparent > that, we could not reach a consensus on a “normative" interface - > application/user needs are multifarious, and most users would rather prefer > developing their own > ZjQcmQRYFpfptBannerStart > This Message Is From an External Sender > This message came from outside your organization. > > ZjQcmQRYFpfptBannerEnd > Hi Jeff, > > From recent discussions in the C++/Languages WG, it was apparent that, we > could not reach a consensus on a “normative" interface - application/user > needs are multifarious, and most users would rather prefer developing their > own C++ solutions over MPI to have better control over application logic > such as serialization (reflection, explicit buffering, etc.) and managing > object lifetimes. OTOH, members agree that having a barebones C++ > interface (like the deleted ones?) may help in designing third-party > high-level interfaces. So, proposing a new interface or binding would most > likely not serve the broader purpose, and compromises that must be baked in > due to MPI semantics may thwart modern C++ developers. > > So, through a series of prospective side documents, the plan is to capture > general guidelines for designing performant C++ interfaces over MPI > (expecting several C++ interface implementations over MPI), considering the > dissonance between the models. > > -- > > Sayan Ghosh > Computer Scientist > Future Computing Technologies Group > Pacific Northwest National Laboratory > (509)-372-6323 • *https://urldefense.us/v3/__https://sg0.github.io__;!!G_uCfscf7eWS!ajr8hPuv5sdt9qjfCwDmAeYnmP_EYcqymJaju91ri-j9tW72jDOu86oT90_Eo5cNuPVRC4mLktpjBph-6eU7aFPTlg$ > <https://urldefense.us/v3/__https://sg0.github.io/__;!!G_uCfscf7eWS!c9LeMozG…>* > > > *From: *mpi-forum <mpi-forum-bounces(a)lists.mpi-forum.org> on behalf of > Jeff Hammond via mpi-forum <mpi-forum(a)lists.mpi-forum.org> > *Date: *Friday, September 12, 2025 at 1:16 AM > *To: *Wes Bland <work(a)wesbland.com> > *Cc: *MPI Forum <mpi-forum(a)lists.mpi-forum.org>, Suggs, Evan < > esuggs(a)tntech.edu>, Uhl, Tim Niklas (SCC) <tim.uhl(a)kit.edu>, Matthias > Schimek <matthias.schimek(a)kit.edu> > *Subject: *Re: [Mpi-forum] Proposal process for a side document for C++ > Language Interface for MPI-5.x > > Check twice before you click! This email originated from outside PNNL. > > This Message Is From an External Sender > This message came from outside your organization. > > > Why do we need a side document? That would be required if we expect > multiple implementations. That makes a lot of sense for Memory > Allocation Kinds because we want that capability in all the > implementations, not just MPICH and OMPI but the downstream > derivatives that may implement it distinctly from what the OSS > upstream projects are doing. I am not convinced that we need more > than one implementation of any C++ interface to MPI. Do we expect > closed-source vendor implementations? Is it likely that this > interface will depend on proprietary internals of any implementation? > > I contend that, for MPI C++ support, we are better off with the Linux > model of having the open-source implementation be the specification. > I am open to being convinced otherwise. > > Jeff > > On Tue, Jul 1, 2025 at 5:30 PM Wes Bland via mpi-forum > <mpi-forum(a)lists.mpi-forum.org> wrote: > > > > Hi Tony, I’ll refer to the procedures doc here: https: //www. mpi-forum. org/docs/other/procedures-36. pdf (*pushes glasses up nose* - Section 2. 2. 5). For side documents, you’ll follow the same procedure as a regular proposal (have a plenary/reading > > ZjQcmQRYFpfptBannerStart > > This Message Is From an External Sender > > This message came from outside your organization. > > > > ZjQcmQRYFpfptBannerEnd > > Hi Tony, > > > > I’ll refer to the procedures doc here: https://urldefense.us/v3/__https://www.mpi-forum.org/docs/other/procedures-… (*pushes glasses up nose* - Section 2.2.5). > > > > For side documents, you’ll follow the same procedure as a regular proposal (have a plenary/reading first, then two votes). The only difference is that updates to side docs incrementing the minor version number only have to pass a single vote (like an errata). > > > > Organizationally, we have repositories for each of the side documents in the main MPI Forum GitHub organization so it’s easier for folks to find them. You can find an example with the newer Memory Allocation Kinds side document here: https://urldefense.us/v3/__https://github.com/mpi-forum/mem-alloc__;!!G_uCf…. I’d be happy to make a repo for you if you’re interested. > > > > I'll put you on the list for the North Carolina meeting. I’m also happy to help schedule a non-voting meeting if you want to get some early feedback during one of our Wednesday time slots. > > > > Thanks, > > Wes > > > > On Jun 26, 2025, at 10:10 AM, Skjellum, Anthony via mpi-forum <mpi-forum(a)lists.mpi-forum.org> wrote: > > > > This Message Is From an External Sender > > This message came from outside your organization. > > Dear Wesley and Martin, how is a side document proposed to the forum? > > > > We wish to prepare a side document. > > > > Also, here is our recent EuroMPI paper describing the thinking and learning of the subcommittee on C++; we would also like to have a chance to share this at the SC25 BOF. > > > > If we can have plenary time at the next meeting, that would be good. North Carolina, right? > > > > Here is the EuroMPI paper from Arxiv: > > > > https://urldefense.us/v3/__https://www.arxiv.org/abs/2506.14610__;!!G_uCfsc… > > > > > > Thanks, > > Tony > > > > > > Anthony Skjellum, PhD > > Professor of Computer Science > > Director, Advanced Scalable Computing, > > Extreme Networks & Data (ASCEND) Center > > Tennessee Technological University > > email: askjellum(a)tntech.edu > > cell: +1-205-807-4968 > > > > > > _______________________________________________ > > mpi-forum mailing list > > mpi-forum(a)lists.mpi-forum.org > > https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi… > > > > > > _______________________________________________ > > mpi-forum mailing list > > mpi-forum(a)lists.mpi-forum.org > > https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi… > > > > -- > Jeff [email protected]://urldefense.us/v3/__http://jeffhammond.github.io/__;!!G_uCfscf7eWS!Z8jqX_bSy2iiaUh4QR-DabaxiRq5JX6mQXKa_9bV0gLTIIUb6Zhhn0hKzbWk65k9ZddzodXLa2yH_heA5DJk3ztaXFqrcRk$ > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi… > -- Anthony Skjellum, PhD skjellum(a)gmail.com Cell: +1-205-807-4968

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Re: [Mpi-forum] Proposal process for a side document for C++ Language Interface for MPI-5.x
by Ghosh, Sayan 12 Sep '25

12 Sep '25

Hi Jeff, >From recent discussions in the C++/Languages WG, it was apparent that, we could not reach a consensus on a “normative" interface - application/user needs are multifarious, and most users would rather prefer developing their own C++ solutions over MPI to have better control over application logic such as serialization (reflection, explicit buffering, etc.) and managing object lifetimes. OTOH, members agree that having a barebones C++ interface (like the deleted ones?) may help in designing third-party high-level interfaces. So, proposing a new interface or binding would most likely not serve the broader purpose, and compromises that must be baked in due to MPI semantics may thwart modern C++ developers. So, through a series of prospective side documents, the plan is to capture general guidelines for designing performant C++ interfaces over MPI (expecting several C++ interface implementations over MPI), considering the dissonance between the models. -- Sayan Ghosh Computer Scientist Future Computing Technologies Group Pacific Northwest National Laboratory (509)-372-6323 • https://urldefense.us/v3/__https://sg0.github.io__;!!G_uCfscf7eWS!c9LeMozG_… <https://urldefense.us/v3/__https://sg0.github.io/__;!!G_uCfscf7eWS!c9LeMozG… > From: mpi-forum <mpi-forum-bounces(a)lists.mpi-forum.org> on behalf of Jeff Hammond via mpi-forum <mpi-forum(a)lists.mpi-forum.org> Date: Friday, September 12, 2025 at 1:16 AM To: Wes Bland <work(a)wesbland.com> Cc: MPI Forum <mpi-forum(a)lists.mpi-forum.org>, Suggs, Evan <esuggs(a)tntech.edu>, Uhl, Tim Niklas (SCC) <tim.uhl(a)kit.edu>, Matthias Schimek <matthias.schimek(a)kit.edu> Subject: Re: [Mpi-forum] Proposal process for a side document for C++ Language Interface for MPI-5.x Check twice before you click! This email originated from outside PNNL. This Message Is From an External Sender This message came from outside your organization. Why do we need a side document? That would be required if we expect multiple implementations. That makes a lot of sense for Memory Allocation Kinds because we want that capability in all the implementations, not just MPICH and OMPI but the downstream derivatives that may implement it distinctly from what the OSS upstream projects are doing. I am not convinced that we need more than one implementation of any C++ interface to MPI. Do we expect closed-source vendor implementations? Is it likely that this interface will depend on proprietary internals of any implementation? I contend that, for MPI C++ support, we are better off with the Linux model of having the open-source implementation be the specification. I am open to being convinced otherwise. Jeff On Tue, Jul 1, 2025 at 5:30 PM Wes Bland via mpi-forum <mpi-forum(a)lists.mpi-forum.org> wrote: > > Hi Tony, I’ll refer to the procedures doc here: https: //www. mpi-forum. org/docs/other/procedures-36. pdf (*pushes glasses up nose* - Section 2. 2. 5). For side documents, you’ll follow the same procedure as a regular proposal (have a plenary/reading > ZjQcmQRYFpfptBannerStart > This Message Is From an External Sender > This message came from outside your organization. > > ZjQcmQRYFpfptBannerEnd > Hi Tony, > > I’ll refer to the procedures doc here: https://urldefense.us/v3/__https://www.mpi-forum.org/docs/other/procedures-… (*pushes glasses up nose* - Section 2.2.5). > > For side documents, you’ll follow the same procedure as a regular proposal (have a plenary/reading first, then two votes). The only difference is that updates to side docs incrementing the minor version number only have to pass a single vote (like an errata). > > Organizationally, we have repositories for each of the side documents in the main MPI Forum GitHub organization so it’s easier for folks to find them. You can find an example with the newer Memory Allocation Kinds side document here: https://urldefense.us/v3/__https://github.com/mpi-forum/mem-alloc__;!!G_uCf…. I’d be happy to make a repo for you if you’re interested. > > I'll put you on the list for the North Carolina meeting. I’m also happy to help schedule a non-voting meeting if you want to get some early feedback during one of our Wednesday time slots. > > Thanks, > Wes > > On Jun 26, 2025, at 10:10 AM, Skjellum, Anthony via mpi-forum <mpi-forum(a)lists.mpi-forum.org> wrote: > > This Message Is From an External Sender > This message came from outside your organization. > Dear Wesley and Martin, how is a side document proposed to the forum? > > We wish to prepare a side document. > > Also, here is our recent EuroMPI paper describing the thinking and learning of the subcommittee on C++; we would also like to have a chance to share this at the SC25 BOF. > > If we can have plenary time at the next meeting, that would be good. North Carolina, right? > > Here is the EuroMPI paper from Arxiv: > > https://urldefense.us/v3/__https://www.arxiv.org/abs/2506.14610__;!!G_uCfsc… > > > Thanks, > Tony > > > Anthony Skjellum, PhD > Professor of Computer Science > Director, Advanced Scalable Computing, > Extreme Networks & Data (ASCEND) Center > Tennessee Technological University > email: askjellum(a)tntech.edu > cell: +1-205-807-4968 > > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi… > > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi… -- Jeff Hammond jeff.science(a)gmail.com https://urldefense.us/v3/__http://jeffhammond.github.io/__;!!G_uCfscf7eWS!Z…

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Re: [Mpi-forum] Proposal process for a side document for C++ Language Interface for MPI-5.x
by Jeff Hammond 12 Sep '25

12 Sep '25

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Re: [Mpi-forum] Non-Voting Meeting - September 10th - Dynamic Process Sets
by Dominik Huber 10 Sep '25

10 Sep '25

Hi all, I’ve attached the slide deck we discussed in today’s meeting. If you’re interested in joining the ongoing conversations in the MPI Sessions WG, we meet every other Monday at 08:00 AM US Central Time / 03:00 PM Central European Summer Time (CEST). Our next meeting is on September 21. Meeting details are available on the Sessions WG wiki page: https://urldefense.us/v3/__https://github.com/mpiwg-sessions/sessions-issue… Best regards, Dominik <https://urldefense.us/v3/__https://github.com/mpiwg-sessions/sessions-issue… > ________________________________ Von: Wes Bland <wesley(a)wesbland.com> Gesendet: Montag, 8. September 2025 22:29:46 An: Wes Bland Cc: MPI Forum; Dominik Huber Betreff: Re: [Mpi-forum] Non-Voting Meeting - September 10th - Dynamic Process Sets Reminder that we have a non-voting meeting this Wednesday from the Sessions WG to discuss dynamic process sets. Connection information in the usual place on the wiki: https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-standard/wiki/V… If that link doesn’t work for you, it’s because you’re not signed into your GitHub account and/or you aren’t a member of the GitHub group. Please let me know if you need access. Thanks, Wes On Aug 26, 2025, at 10:24 AM, Wes Bland via mpi-forum <mpi-forum(a)lists.mpi-forum.org> wrote: This Message Is From an External Sender This message came from outside your organization. Hi all, Now that we’re done with MPI 5.0, it’s time to start working on larger changes that were pushed out a bit while we finished the ABI. To kick that off, Howard Pritchard, Dominik Huber, and the Sessions WG have requested some time before the upcoming Charlotte meeting to discuss dynamic process sets. We’ll meet on Wednesday, September 10th at 10am US Central time<https://urldefense.us/v3/__https://www.worldtimebuddy.com/?qm=1&lid=6,5,264…> (click link for your local time). We reserve two hours for these meetings in case we need the extended time. As always, you can subscribe to the iCal file to get this on your calendar app of choice: https://urldefense.us/v3/__https://calendar.google.com/calendar/ical/g5ms8r… <https://urldefense.us/v3/__https://calendar.google.com/calendar/ical/g5ms8r…> Thanks, Wes _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org<mailto:[email protected]> https://urldefense.us/v3/__https://lists.mpi-forum.org/mailman/listinfo/mpi…

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Reading of Erratum issue for Tools/ABI
by Marc-André Hermanns 10 Sep '25

10 Sep '25

Dear all, we would like to read the following issue in Charlotte: Title: ERRATA: MPI_T handles do not have ABI definition #1001 Issue: https://github.com/mpi-forum/mpi-issues/issues/1001 PR: https://github.com/mpi-forum/mpi-standard/pull/1127 Cheers, Marc-André -- Dr. rer. nat. Marc-André Hermanns [er/sein, he/his] IT Center Group: High Performance Computing Division: Computational Science and Engineering RWTH Aachen University Seffenter Weg 23 52074 Aachen Phone: +49 241 80-24381 hermanns(a)itc.rwth-aachen.de www.itc.rwth-aachen.de Social Media Kanäle des IT Centers: https://blog.rwth-aachen.de/itc/ https://www.facebook.com/itcenterrwth https://www.linkedin.com/company/itcenterrwth https://twitter.com/ITCenterRWTH https://www.youtube.com/@ITCenterRWTHAachen

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Re: [Mpi-forum] Non-Voting Meeting - September 10th - Dynamic Process Sets
by Wes Bland 08 Sep '25

08 Sep '25

Reminder that we have a non-voting meeting this Wednesday from the Sessions WG to discuss dynamic process sets. Connection information in the usual place on the wiki: https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-standard/wiki/V… If that link doesn’t work for you, it’s because you’re not signed into your GitHub account and/or you aren’t a member of the GitHub group. Please let me know if you need access. Thanks, Wes > On Aug 26, 2025, at 10:24 AM, Wes Bland <WORK(a)WESBLAND.COM> wrote: > > Hi all, > > Now that we’re done with MPI 5.0, it’s time to start working on larger changes that were pushed out a bit while we finished the ABI. > > To kick that off, Howard Pritchard, Dominik Huber, and the Sessions WG have requested some time before the upcoming Charlotte meeting to discuss dynamic process sets. > > We’ll meet on Wednesday, September 10th at 10am US Central time <https://urldefense.us/v3/__https://www.worldtimebuddy.com/?qm=1&lid=6,5,264… > (click link for your local time). We reserve two hours for these meetings in case we need the extended time. > > As always, you can subscribe to the iCal file to get this on your calendar app of choice: > > https://urldefense.us/v3/__https://calendar.google.com/calendar/ical/g5ms8r… > > Thanks, > Wes

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