February 2016 - mpi-forum - mailman3.cels.anl.gov

Re: [Mpi-forum] Question about MPI_Info set on communicators
by Jeff Squyres (jsquyres) 16 Feb '16

16 Feb '16

Jim -- Based on your answer, I'm now a bit confused. I now need to back up from my original question and clarify what MPI_COMM_INFO_GET is supposed to return in this scenario: ----- MPI_Info_set(myinfo, "use_shared_memory", "yes"); MPI_Comm_set_info(comm, my info); // MPI implementation recognizes the "use_shared_memory" hint, but is // unable to use shared memory with this communicator MPI_Comm_get_info(comm, myinfo_returned); ----- What value is in myinfo_returned for use_shared_memory? MPI 3.1 6.4.4 p250 says: "MPI_COMM_GET_INFO returns a new info object containing the hints of the communicator associated with comm. The current setting of all hints actually used by the system related to this communicator is returned in info_used." "...all hints actually used by the system..." is actually a bit ambiguous. In this case, "use_shared_memory" is *recognized* by the MPI implementation. But it wasn't able to be *used* (e.g., because no shared memory was available). So is the value in info_used supposed to be: 1. The user's requested hint (i.e., "yes"), or 2. What MPI is actually using (i.e., "no"), or 3. Since this hint wasn't "used" by the system, then the "use_shared_memory" key shouldn't be returned in info_used ? Indeed, one could make the argument that MPI_COMM_GET_INFO is supposed to return exactly the value(s) that the user requested (if it is *recognized* by the implementation), and MPI_T pvars and/or cvars should be queried to obtain the values indicating what the implementation chose to do with those hints. Thoughts? On February 15, 2016 at 8:25:44 PM, Jim Dinan (james.dinan(a)gmail.com) wrote: > "Same" should mean that these call sequences produce the same newcomm, > right? > > MPI_Comm_get_info(comm, myinfo_returned); > MPI_Comm_dup_with_info(comm, &newcomm, myinfo_returned); > > and > > MPI_Comm_dup(comm, &newcomm); > > I think this is an argument for "no". > > I'm not sure if the question is asking whether the MPI implementation can > change communicator info values dynamically. I'm not sure the spec > actually addresses that possibility. If this is allowed, newcomm would > still only get "yes" if the implementation had also toggled the info key on > the parent communicator. > > ~Jim. > > On Mon, Feb 15, 2016 at 5:34 PM, Jeff Squyres (jsquyres) > > wrote: > > > This question has come up in the Open MPI community: > > > > ----- > > MPI_Info_set(myinfo, "use_shared_memory", "yes"); > > MPI_Comm_set_info(comm, myinfo); > > MPI_Comm_get_info(comm, myinfo_returned); > > // Assume here that there was not enough shared memory available to use > > shared-memory for > > // communication on this comm, so MPI_Info_get() tells us that > > use_shared_memory is "no". > > > > // ...time passes, and now assume there is more shared-memory available > > MPI_Comm_dup_with_info(comm, &newcom); > > MPI_comm_get_info(newcom, myinfo_returned); > > ----- > > > > Should newcom have "use_shared_memory" set to "yes" or "no"? > > > > Arguments for "yes": > > - the user originally asked for "yes" > > - now there is shared memory available > > > > Arguments for "no": > > - the current value for "used_shared_memory" on the parent communicator is > > "no" > > > > Which should it be? > > > > MPI-3.1 6.4.2 p238 says: > > > > "...Returns in newcomer a new communicator with the same group or groups, > > same topology, same info hints, any copied cached information, but a new > > context (see Section 6.7.1)." > > > > So the specific question here is: what exactly does "Same info hints" > > mean? The user-specific hint, or the current value of the hint? > > > > -- > > Jeff Squyres > > jsquyres(a)cisco.com > > For corporate legal information go to: > > http://www.cisco.com/web/about/doing_business/legal/cri/ > > _______________________________________________ > > 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 -- 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] Info Assertions Reading
by Jim Dinan 15 Feb '16

15 Feb '16

Hi All, We have updated the proposal with the following new sentence from discussion with the tools folks: https://github.com/mpiwg-p2p/mpi-standard/commit/9bf2a23ae0d86efc68b6e0fc46… The PDF on the ticket has also been updated. Sorry for the last-minute addition; I hope this makes the two-week cutoff. ~Jim. On Wed, Feb 10, 2016 at 9:39 PM, Jim Dinan <james.dinan(a)gmail.com> wrote: > Hello, > > The point-to-point working group will bring forward an updated draft of > the info assertions ticket for a reading in Chicago. The pull request is > posted here: > > https://github.com/mpi-forum/mpi-standard/pull/14 > > And a color-coded PDF copy of the draft is available on the issue page, > here: > > https://github.com/mpi-forum/mpi-issues/issues/11 > > Best, > ~Jim. >

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Re: [Mpi-forum] Question about MPI_Info set on communicators
by Jim Dinan 15 Feb '16

15 Feb '16

"Same" should mean that these call sequences produce the same newcomm, right? MPI_Comm_get_info(comm, myinfo_returned); MPI_Comm_dup_with_info(comm, &newcomm, myinfo_returned); and MPI_Comm_dup(comm, &newcomm); I think this is an argument for "no". I'm not sure if the question is asking whether the MPI implementation can change communicator info values dynamically. I'm not sure the spec actually addresses that possibility. If this is allowed, newcomm would still only get "yes" if the implementation had also toggled the info key on the parent communicator. ~Jim. On Mon, Feb 15, 2016 at 5:34 PM, Jeff Squyres (jsquyres) <jsquyres(a)cisco.com > wrote: > This question has come up in the Open MPI community: > > ----- > MPI_Info_set(myinfo, "use_shared_memory", "yes"); > MPI_Comm_set_info(comm, myinfo); > MPI_Comm_get_info(comm, myinfo_returned); > // Assume here that there was not enough shared memory available to use > shared-memory for > // communication on this comm, so MPI_Info_get() tells us that > use_shared_memory is "no". > > // ...time passes, and now assume there is more shared-memory available > MPI_Comm_dup_with_info(comm, &newcom); > MPI_comm_get_info(newcom, myinfo_returned); > ----- > > Should newcom have "use_shared_memory" set to "yes" or "no"? > > Arguments for "yes": > - the user originally asked for "yes" > - now there is shared memory available > > Arguments for "no": > - the current value for "used_shared_memory" on the parent communicator is > "no" > > Which should it be? > > MPI-3.1 6.4.2 p238 says: > > "...Returns in newcomer a new communicator with the same group or groups, > same topology, same info hints, any copied cached information, but a new > context (see Section 6.7.1)." > > So the specific question here is: what exactly does "Same info hints" > mean? The user-specific hint, or the current value of the hint? > > -- > Jeff Squyres > jsquyres(a)cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > _______________________________________________ > 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] Question about MPI_Info set on communicators
by Jeff Hammond 15 Feb '16

15 Feb '16

The only logical result is for newcomm to have "use_shared_memory"="no", because that is state associated with comm, and what is duplicated is the state of comm. That the user originally provided "use_shared_memory"="yes" is irrelevant to MPI_Comm_dup, because the implementation is not going to track such things, only the actual state that results from the failed attempt to set this key to "yes" during MPI_Comm_set_info, at which point, the communicator only knows "use_shared_memory"="no". The way for the user to have any hope of achieving a "yes" result is to call "MPI_Comm_dup_with_info(comm, myinfo, &newcom);", which will attempt to set "use_shared_memory"="yes" without regards to the prior failed attempt. Hammond On Mon, Feb 15, 2016 at 3:04 PM, Jeff Squyres (jsquyres) <jsquyres(a)cisco.com > wrote: > On February 15, 2016 at 5:58:48 PM, Jeff Hammond (jeff.science(a)gmail.com) > wrote: > > Well, this program will not compile, since MPI_Comm_dup_with_info takes > > three arguments. Furthermore, the info is NOT duplicated and instead the > > second argument is the info the user provides for the new communicator. > > Yeah, that was a typo -- it should be MPI_Comm_dup (i.e., use the info > that was set on the communicator). Here's the correct version: > > ----- > MPI_Info_set(myinfo, "use_shared_memory", "yes"); > MPI_Comm_set_info(comm, myinfo); > MPI_Comm_get_info(comm, myinfo_returned); > // Assume here that there was not enough shared memory available to use > shared-memory for > // communication on this comm, so MPI_Info_get() tells us that > use_shared_memory is "no". > > // ...time passes, and now assume there is more shared-memory available > MPI_Comm_dup(comm, &newcom); > MPI_comm_get_info(newcom, myinfo_returned); > ----- > > -- > Jeff Squyres > jsquyres(a)cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > -- Jeff Hammond jeff.science(a)gmail.com http://jeffhammond.github.io/

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Re: [Mpi-forum] Question about MPI_Info set on communicators
by Jeff Squyres (jsquyres) 15 Feb '16

15 Feb '16

On February 15, 2016 at 5:58:48 PM, Jeff Hammond (jeff.science(a)gmail.com) wrote: > Well, this program will not compile, since MPI_Comm_dup_with_info takes > three arguments. Furthermore, the info is NOT duplicated and instead the > second argument is the info the user provides for the new communicator. Yeah, that was a typo -- it should be MPI_Comm_dup (i.e., use the info that was set on the communicator). Here's the correct version: ----- MPI_Info_set(myinfo, "use_shared_memory", "yes"); MPI_Comm_set_info(comm, myinfo); MPI_Comm_get_info(comm, myinfo_returned); // Assume here that there was not enough shared memory available to use shared-memory for // communication on this comm, so MPI_Info_get() tells us that use_shared_memory is "no". // ...time passes, and now assume there is more shared-memory available MPI_Comm_dup(comm, &newcom); MPI_comm_get_info(newcom, myinfo_returned); ----- -- 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] Question about MPI_Info set on communicators
by Jeff Hammond 15 Feb '16

15 Feb '16

Well, this program will not compile, since MPI_Comm_dup_with_info takes three arguments. Furthermore, the info is NOT duplicated and instead the second argument is the info the user provides for the new communicator. Hammond On Mon, Feb 15, 2016 at 2:34 PM, Jeff Squyres (jsquyres) <jsquyres(a)cisco.com> wrote: > > This question has come up in the Open MPI community: > > ----- > MPI_Info_set(myinfo, "use_shared_memory", "yes"); > MPI_Comm_set_info(comm, myinfo); > MPI_Comm_get_info(comm, myinfo_returned); > // Assume here that there was not enough shared memory available to use shared-memory for > // communication on this comm, so MPI_Info_get() tells us that use_shared_memory is "no". > > // ...time passes, and now assume there is more shared-memory available > MPI_Comm_dup_with_info(comm, &newcom); > MPI_comm_get_info(newcom, myinfo_returned); > ----- > > Should newcom have "use_shared_memory" set to "yes" or "no"? > > Arguments for "yes": > - the user originally asked for "yes" > - now there is shared memory available > > Arguments for "no": > - the current value for "used_shared_memory" on the parent communicator is "no" > > Which should it be? > > MPI-3.1 6.4.2 p238 says: > > "...Returns in newcomer a new communicator with the same group or groups, same topology, same info hints, any copied cached information, but a new context (see Section 6.7.1)." > > So the specific question here is: what exactly does "Same info hints" mean? The user-specific hint, or the current value of the hint? > > -- > Jeff Squyres > jsquyres(a)cisco.com > For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/ > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum -- Jeff Hammond jeff.science(a)gmail.com http://jeffhammond.github.io/

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Re: [Mpi-forum] Question about MPI_Info set on communicators
by Anthony Skjellum 15 Feb '16

15 Feb '16

Jeff, if the value can change over time, is it thread safe? Tony Anthony Skjellum, PhD Professor of Computer Science and Software Engineering COLSA Professor of Cybersecurity and Information Assurance Director of the Auburn Cyber Research Center and Lead Cyber Scientist for Auburn Samuel Ginn College of Engineering Auburn University skjellum(a)auburn.edu or skjellum(a)gmail.com cell: +1-205-807-4968 ; office: +1-334-844-6360 CONFIDENTIALITY: This e-mail and any attachments are confidential and may be privileged. If you are not a named recipient, please notify the sender immediately and do not disclose the contents to another person, use it for any purpose or store or copy the information in any medium. ________________________________________ From: mpi-forum <mpi-forum-bounces(a)lists.mpi-forum.org> on behalf of Jeff Squyres (jsquyres) <jsquyres(a)cisco.com> Sent: Monday, February 15, 2016 4:34 PM To: MPI list Subject: [Mpi-forum] Question about MPI_Info set on communicators This question has come up in the Open MPI community: ----- MPI_Info_set(myinfo, "use_shared_memory", "yes"); MPI_Comm_set_info(comm, myinfo); MPI_Comm_get_info(comm, myinfo_returned); // Assume here that there was not enough shared memory available to use shared-memory for // communication on this comm, so MPI_Info_get() tells us that use_shared_memory is "no". // ...time passes, and now assume there is more shared-memory available MPI_Comm_dup_with_info(comm, &newcom); MPI_comm_get_info(newcom, myinfo_returned); ----- Should newcom have "use_shared_memory" set to "yes" or "no"? Arguments for "yes": - the user originally asked for "yes" - now there is shared memory available Arguments for "no": - the current value for "used_shared_memory" on the parent communicator is "no" Which should it be? MPI-3.1 6.4.2 p238 says: "...Returns in newcomer a new communicator with the same group or groups, same topology, same info hints, any copied cached information, but a new context (see Section 6.7.1)." So the specific question here is: what exactly does "Same info hints" mean? The user-specific hint, or the current value of the hint? -- Jeff Squyres jsquyres(a)cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/ _______________________________________________ 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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Question about MPI_Info set on communicators
by Jeff Squyres (jsquyres) 15 Feb '16

15 Feb '16

This question has come up in the Open MPI community: ----- MPI_Info_set(myinfo, "use_shared_memory", "yes"); MPI_Comm_set_info(comm, myinfo); MPI_Comm_get_info(comm, myinfo_returned); // Assume here that there was not enough shared memory available to use shared-memory for // communication on this comm, so MPI_Info_get() tells us that use_shared_memory is "no". // ...time passes, and now assume there is more shared-memory available MPI_Comm_dup_with_info(comm, &newcom); MPI_comm_get_info(newcom, myinfo_returned); ----- Should newcom have "use_shared_memory" set to "yes" or "no"? Arguments for "yes": - the user originally asked for "yes" - now there is shared memory available Arguments for "no": - the current value for "used_shared_memory" on the parent communicator is "no" Which should it be? MPI-3.1 6.4.2 p238 says: "...Returns in newcomer a new communicator with the same group or groups, same topology, same info hints, any copied cached information, but a new context (see Section 6.7.1)." So the specific question here is: what exactly does "Same info hints" mean? The user-specific hint, or the current value of the hint? -- 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] Tools Readings for March 2016
by Mohror, Kathryn 15 Feb '16

15 Feb '16

Wow, sorry about those crazy links. It looks like LLNL is trying to keep us all safe. Let me try again: o MPIR document: MPIR_being_debugged state: Issue #5 (https://github.com/mpi-forum/mpi-issues/issues/5) Pull request: https://github.com/mpi-forum/mpir/pull/1 o Errata: MPI_T code example error: Issue #12 (https://github.com/mpi-forum/mpi-issues/issues/12) Pull request #7 (https://github.com/mpi-forum/mpi-standard/pull/7) Kathryn _________________________________________________________________ Kathryn Mohror, kathryn(a)llnl.gov, http://scalability.llnl.gov/ Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA > -----Original Message----- > From: mpi-forum [mailto:[email protected]] On Behalf > Of Mohror, Kathryn > Sent: Monday, February 15, 2016 9:13 AM > To: Main MPI Forum mailing list > Subject: [Mpi-forum] Tools Readings for March 2016 > > Hi all, > > The tools group will be reading the following: > o MPIR document: MPIR_being_debugged state: > Issue #5 (https://secure-web.cisco.com/1BvRmuIMZ_ZNlMV3VDPxOX- > I40KSek7xC47OHgANVpnp12RkrWEn2_RhNq8ZXIIcrdJujw26VmDfrmmGp_IvuY > MMV53avg7hdyoMm43-GezNqMURlITT1d- > oVnfJBRz7XrP8U2xMMYXCWKwqYS4ySskKyvPqpgM3yS58uc8dpcTU82se0HaVyL > hxjvcQ1APtWERaW_-EYfvhvrrto_i8BA7R8LhK- > _NFMmq5yJTz2ivnACMMaiXHeoTDsgGP7-R8UgkhkKe7bQ-JFli3ZnszVfT0qyB- > fSWUFF2scjbQeDfRqSUqIMCsGACzhyFY9Vx21xIaJAyczS6FBtCdMCHWzcCm31Q0 > qVh-8c2J2oYxGn74/https%3A%2F%2Fgithub.com%2Fmpi-forum%2Fmpi- > issues%2Fissues%2F5%29 > Pull request: https://secure- > web.cisco.com/1oVadNawZqegiOH91sVLrX6PbO0wSP1pEZFm5T-V4V5K1ziJ7I- > EM2PkC_Wsq_YexjgWT2M- > UVdkM2NABHWah5ge4iIugLh7_72cFTrhSEGi1NGL8drKG68MgMZxAfrvUAnTesI > g4EgQNPvBtjI1dr7mokcJDsKWIvIHz8lGfyY_29rjvCUi4sE2S_ON8ThXQu5jzYA_Yjr > pVq3N1hQmqdD5Ex_TuJCTWtRPwkLEkruMQ08FKYk7SLC_uwD_8UB8TAFRXC6 > W6rn66UDbAvnaPzmc5ro24m- > 0RGBKAUYSK8sih4_0d2FrwSFKWKSQEH2cBlvj6XCq_piEPfJtgTSmzH- > A15VGTqGlTUVM1-8XhuN0/https%3A%2F%2Fgithub.com%2Fmpi- > forum%2Fmpir%2Fpull%2F1 > o Errata: MPI_T code example error: > Issue #12 (https://secure-web.cisco.com/197Cni1_Gqh4PVzakx5cp9- > 8YlzfBZnFknhNjfuDFb5P8rvNhz5hxLMmEwxKXkG2nUyJNa7PJihxXIqHkr2l0jhaV6d > SW8T05s3pkKDehplVJcz6PqMW91R1hHS-oV1Ts9- > BaqIcxs3vNQYFCHoB_Em3gioEt1iPwiQ1iXtEKJszDeKGgSrk4pNj0s0C4hbnthNxIT > QmDZIA4DUFQC_ss7t6bGsnAPpPUV7d3SrIu_TGIfDV7NTcJyKN6jJNyD3TeIKCRLaj > iQULMPZHZp8LceZqbmoJbjb9qh0qYUNpuiHqaFUO3xy7- > Cmdl63b38TbYukdFQYSf101Rtx_50cunQ8W65gax9a3AzZN_d1ltlT4/https%3A%2 > F%2Fgithub.com%2Fmpi-forum%2Fmpi-issues%2Fissues%2F12%29 > Pull request #7 (https://secure- > web.cisco.com/1toQ1iA584lPtu_KsEzV9K0_oHjtfC8fVYrY_K4TwaELJCqsdVglGepi > n_GmyNooBVAEqztJ1R1Ht9Vpiia5GAKhurIFTbGIqtMCvpre5Mm_6rCCfRxnGI2rp > VZ2vSHV8xJVSHNw2BW0IzodFsJiGbt2uPxSnyRq- > e5lREMs_Lp1mcM06MQnMllrr- > O_gQyHyYpm1HsOaGafNCgy_if6KL0BJTK8n2TIJlT9D-VgAd6VqDVteU5Bq- > a473ExIfb9dgntzxNLiXceHgbZmGnFID7a8PoVnpM2AXoZsfaQEikiD9z7J8sjW50LG > uZasPfnE810xMhtwfnLreoJ8iy3_pettmAc_AEvmUrgnNQeY2y0/https%3A%2F%2 > Fgithub.com%2Fmpi-forum%2Fmpi-standard%2Fpull%2F7%29 > > Kathryn > > ________________________________________________________________ > _ > Kathryn Mohror, kathryn(a)llnl.gov, http://scalability.llnl.gov/ Scalability Team > @ Lawrence Livermore National Laboratory, Livermore, CA, USA > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > http://secure- > web.cisco.com/1ehZ7KcpyZksqOls4GJMUH1qXT1iBGEy5ku4pvuQy8ZqGEor9P6K > 8OTCDmaGjR7aW9iRc6Zrcr_z9exPdWhqWLm938hEV2kf21DKho9leEzDoG_DC4 > 9U9pBIljtdYLCl81hrb5sqIV7ySostTyFg0evdhibGAWufqQTybUvHAQ9b_1ynBSheyz > JGV2Z8GQ_SmkC1pLjx5ib1PrpV69Zn2B-LV69ywkB3Pn- > 8tFRmLFHKb1fiCzkxSg29CO9ud43F94O5AZtFDeJXlps5FIW4ngoqf-uou- > ZGUO36YHuhkU5dZo2sU5U5izFqfky6nl0ysF0w- > vroEJaMqtiToMY8qiDfhlZz8AAAtbxGS8kWoQl4/http%3A%2F%2Flists.mpi- > forum.org%2Fmailman%2Flistinfo.cgi%2Fmpi-forum

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Tools Readings for March 2016
by Mohror, Kathryn 15 Feb '16

15 Feb '16

Hi all, The tools group will be reading the following: o MPIR document: MPIR_being_debugged state: Issue #5 (https://github.com/mpi-forum/mpi-issues/issues/5) Pull request: https://github.com/mpi-forum/mpir/pull/1 o Errata: MPI_T code example error: Issue #12 (https://github.com/mpi-forum/mpi-issues/issues/12) Pull request #7 (https://github.com/mpi-forum/mpi-standard/pull/7) Kathryn _________________________________________________________________ Kathryn Mohror, kathryn(a)llnl.gov, http://scalability.llnl.gov/ Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA

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