[openib-general] SA cache design

[Rimmer, Todd]

> From: Sean Hefty [mailto:mshefty at ichips.intel.com]
> 
> Eitan Zahavi wrote:
> > Is the intention to speed up SA queries?
> > Or is it to have persistent storage of them?
> 
> I want both.  :)

I would clarify that the best bang for the effort will be to focus on
the queries which the ULPs themselves will use most often.
For example, the resolution from a node name or Node Guid to a path record.

While a general purpose replica would be nice, it could over complicate the
initial design.

The goal is not to optimize all the queries an end user might desire, but
rather to help avoid the O(N^2) load which thinks like start up of
an MPI or SDP application could cause on the SA.

> and how/when is it invalidated by the SM.
There are a variety of notices already available from the SM which should
be used for the triggering or invalidation.  Such:
GID In/Out of Service
Client Reregistration

It may also be desirable to have the CM upon a failed connect to a given remote node to
trigger the local replica to invalidate and requery for information about remote node.

Todd R.