<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 19, 2015 at 1:14 PM, Rob Latham <span dir="ltr"><<a href="mailto:robl@mcs.anl.gov" target="_blank">robl@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class=""><br>
<br>
On 11/19/2015 03:01 PM, Jeff Hammond wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
That is so cool! Do you have psychic powers or did you actually go from<br>
email to finished code in 65 minutes?<br>
</blockquote>
<br></span>
Pavan maybe has the psychic powers? he asked me work on this a couple months ago.<br>
<br></blockquote><div><br></div><div>That makes sense. Pavan did a Vulcan mind meld on me before I left Argonne :-)</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
but the two implementations have made interesting design choice: OpenMPI went with the "add a lot of flags" approach. Pavan suggested we take an approach that introduces only one new flag (MPIX_COMM_SPLIT_NEIGHBORHOOD) but then uses an info argument to indicate *how* that neighborhood split should occur.<br>
<br></blockquote><div><br></div><div>I strongly favor the info approach, since it is much easier to toggle features on and off as appropriate without thrashing the header.</div><div><br></div><div>If MPICH were to support all the HWLOC options like OpenMPI, having it inside of an info key would be future-proof w.r.t. HWLOC feature changes, unlike an explicit list of types. It also makes it trivial to match the exact syntax of HWLOC commands since info keys are composed of strings.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
As far as an implementation is concerned, both approaches are equivalent.<br>
<br></blockquote><div><br></div><div>Indeed.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
As an end-user, Jeff, do you have an opinion (hah! oh, I kill me... I thought I could type that with a straight face, I really did...) on which approach you prefer?<br>
<br></blockquote><div><br></div><div>I have no opinions, just facts that others have yet to accept as truth ;-)<br><br>Jeff</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
==rob<br>
<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">
Jeff<br>
<br>
On Thu, Nov 19, 2015 at 12:39 PM, Rob Latham <<a href="mailto:robl@mcs.anl.gov" target="_blank">robl@mcs.anl.gov</a><br></span><span class="">
<mailto:<a href="mailto:robl@mcs.anl.gov" target="_blank">robl@mcs.anl.gov</a>>> wrote:<br>
<br>
<br>
<br>
On 11/19/2015 01:34 PM, Jeff Hammond wrote:<br>
<br>
<a href="https://github.com/open-mpi/ompi/pull/320" rel="noreferrer" target="_blank">https://github.com/open-mpi/ompi/pull/320</a> implements features<br>
related to<br>
what was proposed in<br>
<a href="https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/297" rel="noreferrer" target="_blank">https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/297</a> and<br>
<a href="https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/372" rel="noreferrer" target="_blank">https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/372</a>.<br>
<br>
It would be nice if MPICH supported such things as well. Since<br>
MPICH<br>
also uses HWLOC, I imagine it is not too difficult.<br>
<br>
I will file a ticket about this in the absence of objections.<br>
<br>
<br>
<br>
BLAMMO!<br>
<br>
<a href="http://git.mpich.org/mpich-dev.git/shortlog/refs/heads/comsplit_commonfs" rel="noreferrer" target="_blank">http://git.mpich.org/mpich-dev.git/shortlog/refs/heads/comsplit_commonfs</a><br>
<br>
==rob<br>
<br>
<br>
Thanks,<br>
<br>
Jeff<br>
<br>
--<br>
Jeff Hammond<br>
<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a> <mailto:<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a>><br></span>
<mailto:<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a> <mailto:<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a>>><div><div class="h5"><br>
<a href="http://jeffhammond.github.io/" rel="noreferrer" target="_blank">http://jeffhammond.github.io/</a><br>
<br>
<br>
_______________________________________________<br>
To manage subscription options or unsubscribe:<br>
<a href="https://lists.mpich.org/mailman/listinfo/devel" rel="noreferrer" target="_blank">https://lists.mpich.org/mailman/listinfo/devel</a><br>
<br>
<br>
--<br>
Rob Latham<br>
Mathematics and Computer Science Division<br>
Argonne National Lab, IL USA<br>
_______________________________________________<br>
To manage subscription options or unsubscribe:<br>
<a href="https://lists.mpich.org/mailman/listinfo/devel" rel="noreferrer" target="_blank">https://lists.mpich.org/mailman/listinfo/devel</a><br>
<br>
<br>
<br>
<br>
--<br>
Jeff Hammond<br>
<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a> <mailto:<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a>><br>
<a href="http://jeffhammond.github.io/" rel="noreferrer" target="_blank">http://jeffhammond.github.io/</a><br>
<br>
<br>
_______________________________________________<br>
To manage subscription options or unsubscribe:<br>
<a href="https://lists.mpich.org/mailman/listinfo/devel" rel="noreferrer" target="_blank">https://lists.mpich.org/mailman/listinfo/devel</a><br>
<br>
</div></div></blockquote><div class=""><div class="h5">
<br>
-- <br>
Rob Latham<br>
Mathematics and Computer Science Division<br>
Argonne National Lab, IL USA<br>
_______________________________________________<br>
To manage subscription options or unsubscribe:<br>
<a href="https://lists.mpich.org/mailman/listinfo/devel" rel="noreferrer" target="_blank">https://lists.mpich.org/mailman/listinfo/devel</a><br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">Jeff Hammond<br><a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a><br><a href="http://jeffhammond.github.io/" target="_blank">http://jeffhammond.github.io/</a></div>
</div></div>