[mpiwg-coll] [mpiwg-hw-topology] Discussing Semantics and Synchronization Requirements for Neighbourhood Collectives

[Julien.JAEGER at CEA.FR]

Hello Christoph,


it is indeed a good question.


I will also take a look at the table w.r.t. inter-communicators. It may have similar caveats for collectives with inter-communicators.


Best regards,

Julien J.

________________________________
De : mpiwg-hw-topology <mpiwg-hw-topology-bounces at lists.mpi-forum.org> de la part de Christoph Niethammer via mpiwg-hw-topology <mpiwg-hw-topology at lists.mpi-forum.org>
Envoyé : mardi 18 mars 2025 09:15:23
À : mpiwg-hw-topology; mpiwg-semantic-terms at lists.mpi-forum.org; MPI-3 Collective Subgroup Discussions
Cc : Martin Schulz
Objet : [mpiwg-hw-topology] Discussing Semantics and Synchronization Requirements for Neighbourhood Collectives

Hello everyone, During the preparation for the FRM, a question was raised regarding whether and how the semantics of collectives apply to neighborhood collectives. [1] This question stemmed from remark 18) in the summary table in Appendix A. 2,
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Hello everyone,

During the preparation for the FRM, a question was raised regarding
whether and how the semantics of collectives apply to neighborhood collectives. [1]
This question stemmed from remark 18) in the summary table in Appendix A.2,
which was used to apply the semantics of collectives to neighbourhood
collectives at this place.

The discussions expanded during the March meeting to the question of whether remark 18,
stating that "all-to-all collectives *must* synchronize (with some restrictions)",
is correct. [2]

I would like to invite you all to discuss these two issues in more detail during a
Topologies WG meeting on March 27th at 15:00, as part of our regular WG slot.

Best regards
Christoph Niethammer

[1] https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-issues/issues/863__;!!G_uCfscf7eWS!edo6G3QE7JbjtZTTusbpg5yIgnpGmlkZf6PJXEhK0BIFo_p25xzgJ-iVjVZhEuL7z3exLA62R0MjXhpEVDjC5QAigTtN4tiyDa1MnE8$
[2] https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-issues/issues/971__;!!G_uCfscf7eWS!edo6G3QE7JbjtZTTusbpg5yIgnpGmlkZf6PJXEhK0BIFo_p25xzgJ-iVjVZhEuL7z3exLA62R0MjXhpEVDjC5QAigTtN4tiyWCbeaNg$

--

Dr.-Ing. Christoph Niethammer
High Performance Computing Center Stuttgart (HLRS)
Nobelstrasse 19
70569 Stuttgart

Tel: ++49(0)711-685-87203
email: christoph.niethammer at hlrs.de
https://urldefense.us/v3/__https://www.hlrs.de/people/christoph-niethammer__;!!G_uCfscf7eWS!edo6G3QE7JbjtZTTusbpg5yIgnpGmlkZf6PJXEhK0BIFo_p25xzgJ-iVjVZhEuL7z3exLA62R0MjXhpEVDjC5QAigTtN4tiyVz0SIxo$

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