[openib-general] userspace event reporting

[Fab Tillier]

> From: Sean Hefty [mailto:sean.hefty at intel.com]
> Sent: Tuesday, July 12, 2005 12:29 PM
> 
> Currently uCM doesn't associate a data structure with the cm_id.  It passes an
> index directly between the application and the kernel, so adding this would
> require abstracting away the cm_id, which is a fair amount of work.  I don't
> see any other reasonable alternative however.

Actually, it gets a bit messier, since the get_event call would needs an extra
input parameter to identify which CM ID to perform the operation on.  This is a
pretty significant semantic change since an application with many connections
will now need to make many get_event calls, one for each CM ID it wants events
from.  Unless the get_event operation can work asynchronously, this requires a
thread per CM ID, which sucks.

I don't see a clean way to solve this without the above semantic change - the
users can't perform their own reference counting because they don't know which
CM ID will get the next event.

- Fab