[openib-general] [PATCH 1/2] perftest: enhancement to rdma_bw to allow use ofRDMA CM

[Michael S. Tsirkin]

Quoting r. Steve Wise <swise at opengridcomputing.com>:
> Subject: Re: [PATCH 1/2] perftest: enhancement to rdma_bw to allow use ofRDMA CM
> 
> On Thu, 2006-07-06 at 09:20 +0300, Michael S. Tsirkin wrote:
> > Quoting r. Steve Wise <swise at opengridcomputing.com>:
> > > For instance, in the bi-directional bandwidth tests, one side could
> > > finish the test and issue an rdma_disconnect() while the other end still
> > > has pending rdma writes.  This is an error condition in iWARP.  So they
> > > sync up at the end with a message exchange before disconnecting.
> > > 
> > > Make sense?
> > 
> > I see. Is this the only message exchange there is?
> 
> 
> There are 2 message exchanges to comply with IWARP spec: 
> 
> 1) an exchange right after connection setup to force the client to be
> the first side to send an RDMA message.  So the server waits for a RECV
> completion and the client posts a "lets start" SEND.

I don't get this one.  Why can't we just look at command line arguments for
this?  Whoever got the remote IP is the client.  What do you mean by "force
client to be the first"?

> 2) an exchange at the end of the test to ensure all RDMA operations are
> done on the QPs.  Both client and server post a "I'm done" SEND and
> await a "I'm done" completion before disconnecting.

Yes, I think I get this part, and I agree its best to do it this way
for both IB and iWarp.

-- 
MST