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<p>Thanks Sean, I guess assumed that I'd have to handle the case myself, however it shouldn't be too hard to enable a shared memory provider, then use a dedicated endpoint for ranks known to be on the same node. After quickly looking again at the docs, I see
that I missed <em>GNI_XPMEM_ENABLE</em> for the GNI backend, so I'll play with that and see if it makes a difference.</p>
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<p>Cheers</p>
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<p>JB<br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Hefty, Sean <sean.hefty@intel.com><br>
<b>Sent:</b> 10 September 2020 19:22:06<br>
<b>To:</b> Biddiscombe, John A.; libfabric-users@lists.openfabrics.org<br>
<b>Subject:</b> RE: Multiple ranks/instances on the same node</font>
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<div class="PlainText">> If I have multiple processes (ranks) on the same node, and they send messages to each<br>
> other. Does libfabric auto-magically do the right thing and use some kind of shared<br>
> memory for them. If not - can this be enabled by using one of the shared memory<br>
> providers (in conjunction with the gni provider for example) - and if this is the case,<br>
> does one need to use a special endpoint to communicate within node - or will that be<br>
> handled automatically.<br>
<br>
The answer is provider specific. For example, psm/psm2 will use shared memory. Other providers will not. (I'm not sure about gni). A generic solution is unlikely. Shared memory support must be integrated on a provider by provider basis to support proper
tag matching semantics. Ideally, at least rxm and rxd would integrate shared memory support. There's just a developer resource shortage to make that happen.<br>
<br>
- Sean<br>
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