[openib-general] RFC: detecting duplicate MAD requests

[Hal Rosenstock]

On Wed, 2006-06-14 at 17:22, Michael S. Tsirkin wrote:
> Quoting r. Sean Hefty <mshefty at ichips.intel.com>:
> > Subject: Re: RFC: detecting duplicate MAD requests
> > 
> > Michael S. Tsirkin wrote:
> > >>We're kind of left with the same issue of trying to determine if a received
> > >>MAD will generate a response.
> > > 
> > > 
> > > How do you mean? We have IsDS=1 flag for dual-sided, don't we? Dual-sided
> > > transfer always has a response, doesn't it?
> 
> I mean, the flag in the application that says that the transfer is dual-sided.
> The spec seems to imply that user can figure *from the method* that IsDS=1, so I
> assume users will have this logic:
> 
> "2)
> Begin the initial transfer by starting the send operation at the point labelled
> Send. The method or other indication should be interpreted on
> the other side as initiating a double-sided transfer, causing the receive
> context to set IsDS=1."
> 
> 
> So why does the MAD layer care whether a received MAD will generate a resonse?
> A request arrives - we pass it up. Now the ACK for the direction switch arrives
> - we pass it up too, application should be waiting for it, it should take the
> window and pass the response back to us.

The ACKs are transparent to the application/user.

-- Hal