[openib-general] [PATCH for-2.6.18] IB/cma: option to limitMTU to 1K

[Hal Rosenstock]

On Wed, 2006-09-13 at 17:17, Michael S. Tsirkin wrote:
> Quoting r. Hal Rosenstock <halr at voltaire.com>:
> > > If path MTU selector in path query allows MTU 1K (e.g. "best MTU")
> > > and one of the sides is Tavor, select the best MTU that is 1K
> > > and not the largest possible.
> > 
> > How would it be identified if the SA supports this ?
> 
> You mean, if SA ignores mtu selector?

No; I meant detect that one end of the PR request is a Tavor. Wasn't
that part of it ?

If SA doesn't support MTU selector and ignoring MTU selector, it is not
compliant and should be fixed.

> Then we are not worse off than we were before we set it - we get 2K MTU for
> tavor and it works a bit slower.
> 
> > > If path MTU selector requires 2K MTU, return path with 2K MTU.
> > 
> > Also, I'm not sure that this is the required difference in the SA
> > requests :-(
> 
> What do you mean?
> Its not required, but its legal and it will give us better performance.

I mean that there is no requirement on what the IPoIB SA PR request
looks like what you are using to differentiate from the PR requests for
a connection setup.

-- Hal