<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><base href="x-msg://5249/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Wesley, all,</div><div><br></div><div>Here are few comments/suggestions on the slides.</div><div><br></div>Slide 7: There is a mention about "re-enabling wildcard operations". While this is technically true, it is only a side effect of the real operation, acknowledging the local understanding of failure state. This is the reason why the corresponding function is called MPI_Comm_failure_ack and not MPI_Comm_reenable_any_source.<div><br></div><div>Slide 8: - "as it impacts completion" ? What completion?</div><div> - "in the same communicator" is unclear.</div><div><br></div><div>Slide 9: I have few issues with this slide. "How does the application know which request to restart?" Well, if there is anybody that might have the slightest chance to know what requests are still needed … it's the application. Second, I don't see the point of promising a follow-up proposal.</div><div><br></div><div>Slide 10: - Shouldn't be "failed processes"?</div><div> - The need for collective communications is not the only reason to use MPI_Comm_shrink. I would use a more general formulation: "When collective knowledge is necessary…".</div><div> - The MPI_Comm_shrink is doing more than just creating a slimmed down communicator. It validates a global view of all the failed processes in the original communicator on the participating nodes. From my perspective this is more important that creating the new communicator.</div><div><br></div><div>Slide 11: I would suggest to change the wording in order to replace "throw away" by "release". The example on the next slide is doing exactly this.</div><div><br></div><div>Slide 12: This example is __not__ correct as using the same pointer as send and receive buffer in the MPI_Allreduce (use MPI_IN_PLACE instead) is clearly forbidden my the standard.</div><div><br></div><div>Slide 13: I would be careful what you wish for. There are very good reasons why an MPI_Comm_free is a collective call. I would think a little more about this before pushing for a radical requirement.</div><div><br></div><div>Slide 16: This example is not correct without an explicit agreement at every level up the stack. There are many ways for it to fail, too many to let it on the wild.</div><div><br></div><div> George.</div><div><br></div><div><br></div><div><br><div><div>On Aug 16, 2013, at 23:05 , "Sur, Sayantan" <<a href="mailto:sayantan.sur@intel.com">sayantan.sur@intel.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: 'Courier New'; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Ah, gotcha.<o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Sayantan<o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div style="border-style: none none none solid; border-left-width: 1.5pt; border-left-color: blue; padding: 0in 0in 0in 4pt; "><div><div style="border-style: solid none none; border-top-width: 1pt; border-top-color: rgb(181, 196, 223); padding: 3pt 0in 0in; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; "><span class="Apple-converted-space"> </span><a href="mailto:mpi3-ft-bounces@lists.mpi-forum.org">mpi3-ft-bounces@lists.mpi-forum.org</a> [mailto:mpi3-<a href="mailto:ft-bounces@lists.mpi-forum.org">ft-bounces@lists.mpi-forum.org</a>]<span class="Apple-converted-space"> </span><b>On Behalf Of<span class="Apple-converted-space"> </span></b>Wesley Bland<br><b>Sent:</b><span class="Apple-converted-space"> </span>Friday, August 16, 2013 1:55 PM<br><b>To:</b><span class="Apple-converted-space"> </span>MPI 3.0 Fault Tolerance and Dynamic Process Control working Group<br><b>Subject:</b><span class="Apple-converted-space"> </span>Re: [Mpi3-ft] ULFM Slides for Madrid<o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 10pt; font-family: Helvetica, sans-serif; ">I think my slide was unclear. The case I meant was if a process failed before the Allreduce. In that case, the Allreduce would always fail.. If the failure occurs during the algorithm, as you pointed out, it wouldn't necessarily fail everywhere.<o:p></o:p></span></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 10pt; font-family: Helvetica, sans-serif; "> </span></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 10pt; font-family: Helvetica, sans-serif; ">Thanks,<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 10pt; font-family: Helvetica, sans-serif; ">Wesley<o:p></o:p></span></div></div></div></div><p style="margin-right: 0in; margin-left: 0in; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="color: rgb(160, 160, 168); ">On Friday, August 16, 2013 at 3:51 PM, Sur, Sayantan wrote:<o:p></o:p></span></p><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: windowtext; padding: 0in 0in 0in 8pt; margin-left: 0in; margin-top: 5pt; margin-bottom: 5pt; "><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Hi Wesley,</span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Thanks for sending the slides around. Does the assertion on Slide 6 and example on Slide 12 that “Allreduce would always fail” (in the case of failure of one of the participants) hold true?</span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">For example, an MPI implementation might have a terrible implementation of allreduce, where participating ranks send their buffer to a root, which does the reduction. The root then sends the results back to the participants one after the other. One of these p2p sends then fails. In this case, isn’t it possible that one rank gets MPI_ERR_PROC_FAILED, whereas the others get MPI_SUCCESS?</span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Thanks,</span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Sayantan</span><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><o:p></o:p></div><div style="border-style: none none none solid; border-left-width: 1.5pt; border-left-color: blue; padding: 0in 0in 0in 4pt; "><div><div style="border-style: solid none none; border-top-width: 1pt; border-top-color: rgb(181, 196, 223); padding: 3pt 0in 0in; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; "><span class="Apple-converted-space"> </span><a href="mailto:mpi3-ft-bounces@lists.mpi-forum.org" style="color: purple; text-decoration: underline; ">mpi3-ft-bounces@lists.mpi-forum.org</a><span class="Apple-converted-space"> </span>[<a href="mailto:mpi3-ft-bounces@lists.mpi-forum.org" style="color: purple; text-decoration: underline; ">mailto:mpi3-ft-bounces@lists.mpi-forum.org</a>]<span class="Apple-converted-space"> </span><b>On Behalf Of<span class="Apple-converted-space"> </span></b>Wesley Bland<br><b>Sent:</b><span class="Apple-converted-space"> </span>Friday, August 16, 2013 10:17 AM<br><b>To:</b><span class="Apple-converted-space"> </span>MPI3-FT Working Group<br><b>Subject:</b><span class="Apple-converted-space"> </span>[Mpi3-ft] ULFM Slides for Madrid</span><o:p></o:p></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">I've put together a first draft of some slides that give an overview of ULFM for the forum meeting in Madrid for Rich to present. I think I captured most of the discussion we had on the last call relating to rationale, but if I missed something, feel free to add that to this deck or send me edits.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">I think the plan of action, as I understand it from Rich and Geoffroy, is to iterate on these slides until the next call on Tuesday and then we'll go over them as a group to make sure we're all on the same page. Rich, will you be able to attend the call this week (Tuesday, 3:00 PM EST)? If not, we can adjust it this week to make sure you can be there.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">Just to be clear, the goal of this presentation is to provide an overview of ULFM for the European crown that can't usually attend the forum meetings. This will probably be a review for many of the people who attend regularly, but there is some new rationale that we haven't included in the past when we've been putting these presentations together. I'd imagine that this meeting will have some confusion from the attendees where they might remember parts of the previous proposals and mix them, but if we can tell them to do a memory wipe ahead of time, that would help.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">Let me know what I've missed.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <o:p></o:p></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">Thanks,<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">Wesley<o:p></o:p></div></div></div></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">_______________________________________________<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">mpi3-ft mailing list<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="mailto:mpi3-ft@lists.mpi-forum.org" style="color: purple; text-decoration: underline; ">mpi3-ft@lists.mpi-forum.org</a><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-ft" style="color: purple; text-decoration: underline; ">http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-ft</a><o:p></o:p></div></div></div></blockquote><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div></div></div>_______________________________________________<br>mpi3-ft mailing list<br><a href="mailto:mpi3-ft@lists.mpi-forum.org">mpi3-ft@lists.mpi-forum.org</a><br>http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-ft</div></blockquote></div><br></div></body></html>