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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">FABRIC_DIRECT is a building option that providers can choose to support or not. Providers are free to remove the support at any time. Middlewares are not required to test against fabric direct
build. If they do, it is usually only done with the provider(s) in interest that support fabric direct. Even with all current providers removing fabric direct support, leaving the option available may be useful for future providers and doesn’t incur any measurable
maintenance cost by itself.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-family:"Calibri",sans-serif;mso-ligatures:none">From:</span></b><span style="font-family:"Calibri",sans-serif;mso-ligatures:none"> Blocksome, Michael <michael.blocksome@cornelisnetworks.com>
<br>
<b>Sent:</b> Tuesday, February 20, 2024 1:19 PM<br>
<b>To:</b> ofiwg@lists.openfabrics.org; Xiong, Jianxin <jianxin.xiong@intel.com><br>
<b>Subject:</b> libfabric 2.0 and FABRIC_DIRECT<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello all .. apologies, but I missed today’s ofiwg call. <o:p>
</o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I understand that FABRIC_DIRECT w.r.t. libfabric 2.0 was discussed and it was determined that FABRIC_DIRECT would
<b>not</b> be removed in the future. <a id="OWAAM1ED3B19124EE479CB477D9C28C17762A" href="mailto:jianxin.xiong@intel.com"><span style="font-family:"Aptos",sans-serif;text-decoration:none">@Xiong, Jianxin</span></a> - could you summarize the rationale for this
decision for me?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the current “version2” PR (<a href="https://github.com/ofiwg/libfabric/pull/9384">https://github.com/ofiwg/libfabric/pull/9384</a>) the only providers that support FABRIC_DIRECT are opx, psm2, psm3 and tcp – however opx will drop support,
and the psm2 provider could be removed entirely (TBD). The tcp provider is not optimized for latency (it is curious that it supports FABRIC_DIRECT at all). That leaves psm3 as the only provider that supports this feature. Does psm3 really need it? If not,
then removing it would greatly simplify testing and maintenance costs – not just for ofiwg and the psm3 provider, but also for all middleware, etc.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks!<o:p></o:p></p>
<p class="MsoNormal">Mike<o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;mso-ligatures:none">External recipient
<o:p></o:p></span></p>
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