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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">PSB<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> mpiwg-ft [mailto:mpiwg-ft-bounces@lists.mpi-forum.org]
<b>On Behalf Of </b>George Bosilca<br>
<b>Sent:</b> Wednesday, November 27, 2013 2:48 PM<br>
<b>To:</b> MPI WG Fault Tolerance and Dynamic Process Control working Group<br>
<b>Subject:</b> Re: [mpiwg-ft] MPI_Comm_revoke behavior<o:p></o:p></span></p>
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<p class="MsoNormal">On Nov 27, 2013, at 20:33 , Richard Graham <<a href="mailto:richardg@mellanox.com">richardg@mellanox.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">I am thinking about the next step, and have some questions on the semantics of MPI_Comm_revoke()<o:p></o:p></span></p>
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<p class="MsoNormal">What next step are you referring to?<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">[rich] To the full recovery stage. Post what we are talking about now.<o:p></o:p></span></p>
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<p class="MsoNormal" style="text-indent:-.25in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">-</span><span style="font-size:7.0pt"> <span class="apple-converted-space"> </span></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">When
the routine returns, can the communicator ever be used again ? If I remember correctly, the communicator is available for point-to-point traffic, but not collective traffic – is this correct ?<o:p></o:p></span></p>
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<p class="MsoNormal">A revoked communicator is unable to support any communication (point-to-point or collective) with the exception of agree and shrink. If this is not clear enough in the current version of the proposal we should definitively address it.<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">[rich] does this mean all current state (aside from who is alive) associated with the communicator is gone ? Can’t rely on continuing sending pending messages
?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:7.0pt"> <span class="apple-converted-space"> </span></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Looking forward, if one wants to restart the failed ranks (let’s assume we add support
for this), what can be assume about the “repaired” communicator ? What can’t I assume about this communicator ?<o:p></o:p></span></p>
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<p class="MsoNormal">What you can assume depends on what is the meaning of “repaired”. Already today one can spawn new processes and reconstruct a communicator identical to the original communicator before any fault. This can be done using MPI dynamics together
with the agreement available in the ULFM proposal.<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">[rich] This implies that all outstanding traffic is flushed – is this correct ?<o:p></o:p></span></p>
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<p class="MsoNormal"> George.<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Rich<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"CourierNewPSMT","serif"">_______________________________________________<br>
mpiwg-ft mailing list<br>
<a href="mailto:mpiwg-ft@lists.mpi-forum.org"><span style="color:purple">mpiwg-ft@lists.mpi-forum.org</span></a><br>
<a href="http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-ft"><span style="color:purple">http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-ft</span></a><o:p></o:p></span></p>
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