[libfabric-users] memory registration "not needed", with the efa provider?

[Hefty, Sean]

> I'm trying to use the efa provider on an AWS instance that has the Elastic Fabric
> Adaptor high-performance network interface.  In the fi_efa(7) man page for libfabric
> version 1.9.0amzn1.1 installed on the system it says:
> 
> 	The RDM endpoint does not require memory registration
> 
> I was a little in disbelief when I read that, and thus was not surprised when I tried
> simply not making any memory registration calls and sure enough, got internal errors in
> libfabric.  So, what does that statement in the man page mean, exactly?   Is there
> maybe a magic remote key value that means "I didn't register memory."?  I'm just using
> 0UL, in the absence of any other guidance.

My guess is that they mean, "memory registration is not required for send or receive buffers".

That is, EFA likely doesn't require FI_MR_LOCAL.

Registration is always required for RMA target buffers for security reasons.

- Sean