[ofa-general] Memory registration redux

[Tziporet Koren]

Jeff Squyres wrote:
> Roland and I chatted on the phone today; I think I now understand 
> Roland's counter-proposal (I clearly didn't before).  Let me try to 
> summarize:
>
> 1. Add a new verb for "set this userspace flag to 1 if mr X ever 
> becomes invalid"
> 2. Add a new verb for "no longer tell me if mr X ever becomes invalid" 
> (i.e., remove the effects of #1)
> 3. Add run-time query indicating whether #1 works
> 4. Add [optional] memory registration caching to libibverbs
>
> Prior to talking to Roland, I had envisioned *one* flag in userspace 
> that indicated whether any memory registrations had become invalid.  
> Roland's idea is that there is one flag *per registration* -- you can 
> instantly tell whether a specific registration is valid.
>
> Given this, let's keep the discussion going here in email -- perhaps 
> the teleconference next Monday may become moot.
I think the new proposal is good (but I am not MPI expert)
If we implement it soon we will be able to enable it in OFED 1.5 too
I think the cache in libibverbs can be delayed since it can be added 
after the API will the kernel is avilable

Tziporet