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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">To the best of my knowledge, IB verbs does support this. Please look at the MVAPICH code for more details.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Best,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hari.<o:p></o:p></span></p>
<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"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Niyaz Murshed <Niyaz.Murshed@arm.com>
<br>
<b>Sent:</b> Wednesday, August 21, 2024 12:20 PM<br>
<b>To:</b> Subramoni, Hari <subramoni.1@osu.edu>; Announcement about MVAPICH (MPI over InfiniBand, RoCE, Omni-Path, Slingshot, iWARP and EFA) Libraries developed at NBCL/OSU <mvapich-discuss@lists.osu.edu><br>
<b>Cc:</b> nd <nd@arm.com>; Subramoni, Hari <subramoni.1@osu.edu><br>
<b>Subject:</b> Re: RDMA memory registration for AllGather<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="mso-line-height-alt:.75pt"><span style="font-size:1.0pt;color:white">ibv_reg_mr takes in PD and buffer. Each PD is associated with a HCA. If we register the buffer with multiple PDs, it can be access by all HCAs? My understanding
from another source is that “ibverbs” do not support this. ‘Some providers (e.</span><span style="font-size:1.0pt;font-family:"Arial",sans-serif;color:white"> </span><span style="font-size:1.0pt;color:white">g.</span><span style="font-size:1.0pt;font-family:"Arial",sans-serif;color:white"> </span><span style="font-size:1.0pt;color:white"><o:p></o:p></span></p>
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<p class="MsoNormal"> <a href="https://us-phishalarm-ewt.proofpoint.com/EWT/v1/KGKeukY!vwQdMSZND6YBZRdwP87EmWXS6Y97NEu4enmmpDPsBZ5klIXK3WFg9faxwumef21rksMl9U6XVJC8OUi9XJCKOuuCA8Lm7ZIeUhkYNUVkDC_kZBEXfU3jNqZzZ1FpINLCb4YFB-t89hrKZw$" target="_blank"><strong><span style="font-size:10.5pt;font-family:"Arial",sans-serif;color:black;border:solid #666666 1.0pt;padding:6.0pt;font-weight:normal;text-decoration:none"> Report Suspicious </span></strong></a>
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<p class="MsoNormal"><span style="font-size:11.0pt">ibv_reg_mr takes in PD and buffer. Each PD is associated with a HCA.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">If we register the buffer with multiple PDs, it can be access by all HCAs?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">My understanding from another source is that “ibverbs” do not support this.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">‘Some providers (e.g. verbs) map domain to a specific nic and thus can't share MR among nics.’<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://urldefense.com/v3/__https:/lists.openfabrics.org/pipermail/libfabric-users/2024-August/001072.html__;!!KGKeukY!xMFkSH86qg6fBW46tJgDLuhq5P_0tpSXJ3qurJx7iZBbndqKnHCU0DQuOCoJwgo3ht4dC7kXZu8uGBQpjH3sOCM$">https://lists.openfabrics.org/pipermail/libfabric-users/2024-August/001072.html</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">Subramoni, Hari <<a href="mailto:subramoni.1@osu.edu">subramoni.1@osu.edu</a>><br>
<b>Date: </b>Wednesday, August 21, 2024 at 11:15</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black"> </span><span style="font-size:12.0pt;color:black">AM<br>
<b>To: </b>Niyaz Murshed <<a href="mailto:Niyaz.Murshed@arm.com">Niyaz.Murshed@arm.com</a>>, Announcement about MVAPICH (MPI over InfiniBand, RoCE, Omni-Path, Slingshot, iWARP and EFA) Libraries developed at NBCL/OSU <<a href="mailto:mvapich-discuss@lists.osu.edu">mvapich-discuss@lists.osu.edu</a>><br>
<b>Cc: </b>nd <<a href="mailto:nd@arm.com">nd@arm.com</a>>, Subramoni, Hari <<a href="mailto:subramoni.1@osu.edu">subramoni.1@osu.edu</a>><br>
<b>Subject: </b>RE: RDMA memory registration for AllGather<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi, Niyaz.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">One buffer can be registered with multiple HCAs. There is no problem with this. You just to call ibv_reg_mr multiple times.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Thx,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hari.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Mvapich-discuss <<a href="mailto:mvapich-discuss-bounces@lists.osu.edu">mvapich-discuss-bounces@lists.osu.edu</a>>
<b>On Behalf Of </b>Niyaz Murshed via Mvapich-discuss<br>
<b>Sent:</b> Tuesday, August 20, 2024 3:18 PM<br>
<b>To:</b> Niyaz Murshed via Mvapich-discuss <<a href="mailto:mvapich-discuss@lists.osu.edu">mvapich-discuss@lists.osu.edu</a>><br>
<b>Cc:</b> nd <<a href="mailto:nd@arm.com">nd@arm.com</a>><br>
<b>Subject:</b> [Mvapich-discuss] RDMA memory registration for AllGather</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:1.0pt;color:white">Hello all , I am trying to understand how a single memory buffer is registered to multiple rdma verbvs context in case there are data coming in from different interfaces. As I understand, we can
only register RDMA memory to a single protection</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">Hello all , </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I am trying to understand how a single memory buffer is registered to multiple rdma verbvs context in case there are data coming in from different interfaces.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">As I understand, we can only register RDMA memory to a single protection domain which is linked to one interface.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Assuming we receive data from 3 ranks on interface1 and 2 ranks from interface 2, how do these interfaces write to same common buffer ?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">How is the same buffer registered to 2 interfaces?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Regards,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Niyaz</span><o:p></o:p></p>
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