[ewg] Re: RFCv2: SRC API

[Michael S. Tsirkin]

> Quoting Tang, Changqing <changquing.tang at hp.com>:
> Subject: RE: RFCv2: SRC API
> 
> 
> > 
> > > Is there any performance worry to let j2(the first job on a 
> > node) to 
> > > do all the "work" ?
> > 
> > How do you mean?
> 
> I mean that j2 has all the QP connections with all other remote jobs, so
> j2 does not save anything compared with non-SRC case, can this affect
> j2's performance ?
> 
> I have another question, when using SRQ, or SRC+SRQ, when a completion
> is returned by ibv_poll_cq(),  is there an easy way to find who sent
> this message to me ? 'struct ibv_wc' does not say much about the message
> source rank. The only field is 'src_qp', but I can not find any document
> about how to use it.

There's also qp_num.

> Is there any way to return some kind of "source context" ?
> 
> Or do you think this is application's responsibility to figure out
> source rank from the message itself ? I hope the source rank can be
> identified before parsing the message.
> 
> Thanks.

How about using send with immediate, and sticking the rank in
the immediate data?

-- 
MST