[openib-general] RE: userspace event reporting

[Fab Tillier]

> From: Libor Michalek [mailto:libor at topspin.com]
> Sent: Wednesday, July 20, 2005 5:02 PM
> 
>   My question is do we really want this, since an application will likely
> have yet another table containing the app specific connection structure.
> How that table is locked and managed will differ based on the threading
> model. I think it's an incorrect assumption that if we create this level
> thread safety in the uCM then the app connection structure can be placed
> in a uCM user supplied pointer (e.g. the kCM context variable) and avoid
> this type of app level connection table.

Ok, now that I think more about it, I think that having the ability to do an
async, per-CM ID get_event call would help tremendously.  The application knows
what CM IDs it has, and thus can initiate such a get_event request for each.
The app can then maintain its own reference count on its internal structures
(which is really what is needs to do), rather than rely on the CM providing the
reference counting and synchronization.

Is it even possible to make async get_event requests, from a coding perspective?
Would the resulting usage model work for clients?  If using an AIO read request,
could the file offset could be used to convey the CM ID being polled?

- Fab