[ofiwg] send/recv "credits"

[Reese Faucette (rfaucett)]

> During the call, I asked what if send completions are suppressed. Someone
> replied that as long as I have a completion on the last send, I can recover the
> resources/credits. But if they are variable length and especially with
> inline/inject sends, then I cannot do so easily without assuming each send is
> maximally large.

Without commenting on relative merits of credit vs EAGAIN, 2 comments -

1) remember, no one is suggesting that app writers are required to use credits, -EAGAIN model is always available, no app writer is being forced into anything
2) even when using credit model, apps don't need to do the credit accounting as suggested above.  Provider will do the credit accounting and available credits can be queried via a very cheap function, so send without completion is not an issue.

-r