[openib-general] RDMA_READ SGE

[Tom Tucker]

[...snip...]
> Practically I don't see reporting the exact values as a priority -
> I think applications really can figure this out easier by attempting
> operating with relevant parameters and fallback to smaller values
> on failure.

Perhaps it's not a priority, and it is certainly technically possible,
however, I would say that this is quite a burden to place on every
application to attempt to discover limits by submitting WR and checking
when they fail. Who do they talk to while they're doing all this? 

It seems to me that it would be better to expand the set of attributes.
Leave the current max_sge for backward compatibility, but let apps
reliably query limits instead of attempting to discover them through
trial and error.


> But assuming that applications really need this information -
> it seems we really should generalize this - maybe make the device provide
> a function mapping QP attributes and operation kinds to the max set of values
> allowed?
>