[ofa-general] Re: RFCv2: SRC API

[Michael S. Tsirkin]

> Quoting Tang, Changqing <changquing.tang at hp.com>:
> Subject: RE: RFCv2: SRC API
> 
>  
> > +When job j1 needs to transmit to job j2 on remote node n for 
> > the first time:
> > +1. Test: does job j1 have an existing connection to some job 
> > on node n?
> > +        - If no:
> > +		j1 creates an SRC QP qp1 (send QP)
> > +			qp1 is only used to post send WRs
> > +		j2 creates an SRC QP qp2
> > +			qp2 is part of SRC domain
> > +			qp2 is only used to do transport checks:
> > +				neither send nor receive WRs 
> > are posted on qp2
> > +		j1 and j2 create a connection between qp1 and qp2
> > +	- If yes:
> > +		let qp1 be the QP which belongs to j1 and is connected
> > +			to some qp on node n
> > +
> > +2. j1 gets SRQ number from j2
> > +3. j1 can now use QP qp2 from step 1
> > +   and SRQ number from step 3 to send data to j2
> > +
> > +Cleanup:
> > +When job j1 does not need to communicate to any jobs on node n, it 
> > +disconnects qp1 from qp2, and asks j2 to destroy qp2.
> 
> Suppose remote node n has j2/qp2, j3/qp3, j4/qp4,

You got it wrong, j3 and j4 do not need to create QPs
to get packets from j1.

> qp1 on j1 is connected
> to qp2, then there is no need to make connection between qp1 and qp3,
> qp1 and qp4, there are automatically connected, right ?  Then how can j3
> know that j2 has connected to j1, it does not need to make connection
> again ?
> 
> qp1 find destination by SRQ number only, so "+3. j1 can now use QP qp2
> from step 1", what does it mean ?
> 
> Can we destroy qp2 on j2 first, and keep j1 and j3 continue to
> communicate ?

Communication is only possible as long as both qp1 and qp2 exist.

-- 
MST