<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">If there is a resource associated with the object, e.g., memory, you would not want to free it until the object was destroyed. MPI_xxx_FREE has the semantic effect of decrementing a reference count, not necessarily destroying the object. (Sorry if I'm missing the context - I was not on the call).<div><br></div><div>Bill</div><div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; 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-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div style="font-size: 12px; ">William Gropp</div><div style="font-size: 12px; ">Director, Parallel Computing Institute</div><div style="font-size: 12px; ">Deputy Director for Research</div><div style="font-size: 12px; ">Institute for Advanced Computing Applications and Technologies</div></div></div></span><span class="Apple-style-span" style="font-size: 12px; ">Thomas M. Siebel Chair in Computer Science</span><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div style="font-size: 12px; ">University of Illinois Urbana-Champaign</div></div><div><br></div></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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<br><div><div>On Jul 1, 2013, at 12:33 PM, Jeff Squyres (jsquyres) wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On Jul 1, 2013, at 1:24 PM, "David Goodell (dgoodell)" <<a href="mailto:dgoodell@cisco.com">dgoodell@cisco.com</a>> wrote:<br><br><blockquote type="cite">----8<----<br></blockquote><blockquote type="cite"><blockquote type="cite"><span class="Apple-tab-span" style="white-space:pre"> </span>• Jeff also brings up the idea of a callback (or some kind of MPI_T notification) to know when an MPI object is destroyed (per email conversation w/ Jeff, Kathryn, Martin).<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>• Marc-Andre will think about whether it will be useful for any tools to know when MPI objects get destroyed.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>• Marc-Andre will also think about whether it would be useful for there to be an MPI_T mechanism to get some kind of unique ID for an MPI object (that will be durable after the handle is freed). This way, a tool can track the entire lifecycle of an object -- not just its handle.<br></blockquote></blockquote><blockquote type="cite">----8<----<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I was unable to attend the call, but why isn't attaching an attribute with a destructor callback to the object in question sufficient? Is it because we have MPI opaque objects which do not support attributes (e.g., MPI_Op)?<br></blockquote><br><br>Today's attribute calls give you a callback when MPI_*_FREE is invoked -- when is potentially not when the object is actually destroyed.<br><br>The Fab+Jeff idea was wondering if anyone cares about the difference between these two; are there any useful use cases where someone could benefit from knowing when the object was actually destroyed?<br><br>-- <br>Jeff Squyres<br><a href="mailto:jsquyres@cisco.com">jsquyres@cisco.com</a><br>For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/<br><br><br>_______________________________________________<br>Mpi3-tools mailing list<br>Mpi3-tools@lists.mpi-forum.org<br>http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools<br></div></blockquote></div><br></div></body></html>