- mpiwg-rma - mailman3.cels.anl.gov

Re: [Mpi3-rma] draft of a proposal for RMA interfaces
by Howard Pritchard 16 Oct '08

16 Oct '08

Hello Rich, I meant to respond earlier to Vinod's proposal, sorry for the delay. First a minor correction in section 5.1. I think the prhase: /the GET transfers from the caller memory(origin) to the target memory; PUT transfer data from the target memory to the caller memory/ near the beginning of section. I think overall the proposal looks interesting. I am somewhat confused by the MPI_Req_set_attr and MPI_Req_get_attr and how they are suppose to be used. The main item that is missing seems to be a method for signaling completion of an rma operation at a remote process. Is the assumption that if this was required, the remote process would spin wait on a volatile? This would seem to introduce other problems - like how to 'emulate' this functionality using point-to-point protocols. I believe that any new rma proposal needs to have semantics such that one could base a correct, if low performance, implementation using point-to-point communication protocols. Howard Richard Graham wrote: > Just to get discussion going again. Talking with several folks I have > heard several concerns expressed about the proposal. I think it would > be good if these (and others) could be raised on the list, so we can > start discussion. We can continue this next week in Chicago, but Vinod > will not be able to make this meeting, so an e-mail discussion will help. > > Here are the issues I have hear of so far: > - May not work well on current h/w that is not cache coherent, as it > requires a remote thread in this case. I believe this is for the SX > series of machines, but Jesper please correct me if I am wrong here. > What would be an alternative approach that could provide expected > performance on platforms that may require work on the remote end for > RMA for correctness, and work well on platforms that do require very > specific remote cache management (or other actions) for correctness ? > - Concern about future high-end platforms, under that assumption that > these will not be cache coherent (and will actually have caches ï¿½ if > they donï¿½t this is not a concern), and therefore this proposal is > aimed at a short-lived technical capability. > - What is missing ? > > Rich > > > On 9/6/08 6:06 PM, "Vinod tipparaju" <tipparajuv(a)hotmail.com> wrote: > > > > Rajeev, > > Excellent questions. > > Technically, yes. However, ARMCI does more thinking about Global > Arrays. Particularly because of stride data transfers (multiple > stride levels). However, I don't see why we cannot have an > alternative port. The only way to know is to prototype the > interfaces, implement Global Arrays on top of them and see how the > interfaces fare. From superficial thinking, I think they will do > just fine ;-). We however cannot say this about all potential > implementations. > > I am not sure if Dan Bonachea is a member of this list. I will > write him a message if he isn't. > > Thanks, > Vinod. > > ---------------------------------------- >> From: thakur(a)mcs.anl.gov >> To: mpi3-rma(a)lists.mpi-forum.org >> Date: Sat, 6 Sep 2008 16:24:35 -0500 >> Subject: Re: [Mpi3-rma] draft of a proposal for RMA interfaces >> >> Vinod, >> Thanks for the proposal and the nice presentation. A question I had >> was does it meet the needs of the Global Arrays library? That is, > if this >> were available in MPI today, would you implement Global Arrays > with MPI and >> nothing else (not ARMCI). Similarly, it would be good to run it > by Dan >> Bonachea and see what he has to say regarding implementing UPC. >> >> Regards, >> Rajeev >> >> >>> -----Original Message----- >>> From: mpi3-rma-bounces(a)lists.mpi-forum.org >>> [mailto:[email protected]] On Behalf Of >>> Vinod tipparaju >>> Sent: Thursday, September 04, 2008 1:50 AM >>> To: mpi3-rma(a)lists.mpi-forum.org >>> Subject: [Mpi3-rma] draft of a proposal for RMA interfaces >>> >>> >>> Folks, >>> >>> Attached is a draft of a new proposal for MPI3-RMA interfaces >>> for your perusal. >>> >>> Thanks, >>> Vinod Tipparaju, ORNL. >>> >> >> _______________________________________________ >> mpi3-rma mailing list >> mpi3-rma(a)lists.mpi-forum.org >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma > > _______________________________________________ > mpi3-rma mailing list > mpi3-rma(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma > >------------------------------------------------------------------------ > >_______________________________________________ >mpi3-rma mailing list >mpi3-rma(a)lists.mpi-forum.org >http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma > > -- Howard Pritchard Cray Inc.

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[Mpi3-rma] A mild extension/restriction: Registration of datatypes/ops for one-sided communication
by Jesper Larsson Traeff 16 Oct '08

16 Oct '08

dear all, I've added a small proposal on registration of datatypes/ops for one-sided communication for discussion. It is ticket #35. This proposal concerns the use of derived datatypes and is orthogonal to the other proposals so far jesper

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Re: [Mpi3-rma] draft of a proposal for RMA interfaces
by Richard Graham 16 Oct '08

16 Oct '08

Just to get discussion going again. Talking with several folks I have heard several concerns expressed about the proposal. I think it would be good if these (and others) could be raised on the list, so we can start discussion. We can continue this next week in Chicago, but Vinod will not be able to make this meeting, so an e-mail discussion will help. Here are the issues I have hear of so far: - May not work well on current h/w that is not cache coherent, as it requires a remote thread in this case. I believe this is for the SX series of machines, but Jesper please correct me if I am wrong here. What would be an alternative approach that could provide expected performance on platforms that may require work on the remote end for RMA for correctness, and work well on platforms that do require very specific remote cache management (or other actions) for correctness ? - Concern about future high-end platforms, under that assumption that these will not be cache coherent (and will actually have caches if they don¹t this is not a concern), and therefore this proposal is aimed at a short-lived technical capability. - What is missing ? Rich On 9/6/08 6:06 PM, "Vinod tipparaju" <tipparajuv(a)hotmail.com> wrote: > > > Rajeev, > > Excellent questions. > > Technically, yes. However, ARMCI does more thinking about Global Arrays. > Particularly because of stride data transfers (multiple stride levels). > However, I don't see why we cannot have an alternative port. The only way to > know is to prototype the interfaces, implement Global Arrays on top of them > and see how the interfaces fare. From superficial thinking, I think they will > do just fine ;-). We however cannot say this about all potential > implementations. > > I am not sure if Dan Bonachea is a member of this list. I will write him a > message if he isn't. > > Thanks, > Vinod. > > ---------------------------------------- >> > From: thakur(a)mcs.anl.gov >> > To: mpi3-rma(a)lists.mpi-forum.org >> > Date: Sat, 6 Sep 2008 16:24:35 -0500 >> > Subject: Re: [Mpi3-rma] draft of a proposal for RMA interfaces >> > >> > Vinod, >> > Thanks for the proposal and the nice presentation. A question I had >> > was does it meet the needs of the Global Arrays library? That is, if this >> > were available in MPI today, would you implement Global Arrays with MPI and >> > nothing else (not ARMCI). Similarly, it would be good to run it by Dan >> > Bonachea and see what he has to say regarding implementing UPC. >> > >> > Regards, >> > Rajeev >> > >> > >>> >> -----Original Message----- >>> >> From: mpi3-rma-bounces(a)lists.mpi-forum.org >>> >> [mailto:[email protected]] On Behalf Of >>> >> Vinod tipparaju >>> >> Sent: Thursday, September 04, 2008 1:50 AM >>> >> To: mpi3-rma(a)lists.mpi-forum.org >>> >> Subject: [Mpi3-rma] draft of a proposal for RMA interfaces >>> >> >>> >> >>> >> Folks, >>> >> >>> >> Attached is a draft of a new proposal for MPI3-RMA interfaces >>> >> for your perusal. >>> >> >>> >> Thanks, >>> >> Vinod Tipparaju, ORNL. >>> >> >> > >> > _______________________________________________ >> > mpi3-rma mailing list >> > mpi3-rma(a)lists.mpi-forum.org >> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma > > _______________________________________________ > mpi3-rma mailing list > mpi3-rma(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma >

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Re: [Mpi3-rma] draft of a proposal for RMA interfaces
by Vinod tipparaju 06 Sep '08

06 Sep '08

Rajeev, Excellent questions. Technically, yes. However, ARMCI does more thinking about Global Arrays. Particularly because of stride data transfers (multiple stride levels). However, I don't see why we cannot have an alternative port. The only way to know is to prototype the interfaces, implement Global Arrays on top of them and see how the interfaces fare. From superficial thinking, I think they will do just fine ;-). We however cannot say this about all potential implementations. I am not sure if Dan Bonachea is a member of this list. I will write him a message if he isn't. Thanks, Vinod. ---------------------------------------- > From: thakur(a)mcs.anl.gov > To: mpi3-rma(a)lists.mpi-forum.org > Date: Sat, 6 Sep 2008 16:24:35 -0500 > Subject: Re: [Mpi3-rma] draft of a proposal for RMA interfaces > > Vinod, > Thanks for the proposal and the nice presentation. A question I had > was does it meet the needs of the Global Arrays library? That is, if this > were available in MPI today, would you implement Global Arrays with MPI and > nothing else (not ARMCI). Similarly, it would be good to run it by Dan > Bonachea and see what he has to say regarding implementing UPC. > > Regards, > Rajeev > > >> -----Original Message----- >> From: mpi3-rma-bounces(a)lists.mpi-forum.org >> [mailto:[email protected]] On Behalf Of >> Vinod tipparaju >> Sent: Thursday, September 04, 2008 1:50 AM >> To: mpi3-rma(a)lists.mpi-forum.org >> Subject: [Mpi3-rma] draft of a proposal for RMA interfaces >> >> >> Folks, >> >> Attached is a draft of a new proposal for MPI3-RMA interfaces >> for your perusal. >> >> Thanks, >> Vinod Tipparaju, ORNL. >> > > _______________________________________________ > mpi3-rma mailing list > mpi3-rma(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma

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Re: [Mpi3-rma] draft of a proposal for RMA interfaces
by Rajeev Thakur 06 Sep '08

06 Sep '08

Vinod, Thanks for the proposal and the nice presentation. A question I had was does it meet the needs of the Global Arrays library? That is, if this were available in MPI today, would you implement Global Arrays with MPI and nothing else (not ARMCI). Similarly, it would be good to run it by Dan Bonachea and see what he has to say regarding implementing UPC. Regards, Rajeev > -----Original Message----- > From: mpi3-rma-bounces(a)lists.mpi-forum.org > [mailto:[email protected]] On Behalf Of > Vinod tipparaju > Sent: Thursday, September 04, 2008 1:50 AM > To: mpi3-rma(a)lists.mpi-forum.org > Subject: [Mpi3-rma] draft of a proposal for RMA interfaces > > > Folks, > > Attached is a draft of a new proposal for MPI3-RMA interfaces > for your perusal. > > Thanks, > Vinod Tipparaju, ORNL. >

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[Mpi3-rma] draft of a proposal for RMA interfaces
by Vinod tipparaju 04 Sep '08

04 Sep '08

Folks, Attached is a draft of a new proposal for MPI3-RMA interfaces for your perusal. Thanks, Vinod Tipparaju, ORNL.

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[Mpi3-rma] New Wiki page for MPI RMA discussions
by William Gropp 03 Jul '08

03 Jul '08

I've added a wiki page for comments and discussions on the flexible RMA proposal. Please make use of that to continue the discussion of that proposal (the proposal and presentation are also on the wiki page). Bill William Gropp Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign

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[Mpi3-rma] A very modest proposal (Datatypes/Ops in RMA)
by Jesper Larsson Traeff 23 Apr '08

23 Apr '08

Dear all, here is a proposal for registration of datatypes/ops for one-sided communication with the aim of making implementations easier (in some cases) and providing more flexibility (user-defined operations in accumulate). It's for discussion and not a finished proposal Jesper

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[Mpi3-rma] RMA working group meeting
by Rajeev Thakur 21 Apr '08

21 Apr '08

A meeting of the RMA working group has been scheduled for Wednesday morning (http://meetings.mpi-forum.org/secretary/2008/04/agenda.php) In addition to presentations of the two proposals so far, if there are any other agenda items, let us know. Rajeev

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[Mpi3-rma] MPI RMA Agenda Items for April Meeting
by William Gropp 16 Apr '08

16 Apr '08

Thanks go to Hubert for a detailed proposal; its now on the agenda for the MPI3 RMA discussions at the next MPI meeting. Please submit other agenda items this week. Thanks! Bill and Rajeev William Gropp Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign

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