[openib-general] Re: Re: Re: [PATCH] change Mellanox SDP workaround toa moduleparameter

[Hal Rosenstock]

On Tue, 2006-02-21 at 16:09, Michael S. Tsirkin wrote:
> Quoting Hal Rosenstock <halr at voltaire.com>:
> > > Assuming the spec says as it is, then:
> > > 1. CMA needs to be modified to retry the connection if its rejected because
> > >    of lower MTU.
> > > 2. SDP/SRP protocols specs need a clarification: e.g. current SDP spec
> > >    says the connection should be closed when we get a REJ.
> > 
> > Can you be specific about the spec citations for SDP and SRP for REJ
> > handling ? Isn't it more the retry strategy once the connection is
> > REJected ? Is that in those specs ?
> 
> This is not explicitly explained in spec. I think Dror discussed the use of
> REJ/retry to get the MTU in his mail in sufficient detail.

Sorry for being dense but this is what Dror wrote:
"The SWG defined a generic mechanism which uses REJ to indicate that 
the passive side does not accept a certain REQ fields, and allows the
passive side to indicate an alternative value. Indirection is also
supported through the same protocol. It also allows the active side,
following the REJ, to use an alternate value, other than the one
suggested by the passive side, i.e. passive side only has a veto
capability."

So the only issue here is the inefficiency in terms of the back and
forth of CM messages to get to the 1K MTU connection. How important is
connection rate for SDP and SRP ? If not, can't we live with how things
are ?

-- Hal