[openib-general] [RFC] Notice/InformInfo event reporting

[Sean Hefty]

Rimmer, Todd wrote:
> In a functioning fabric, events will be rare.  However its when you
> first boot the fabric, reboot the SM or other similar "start up" actions
> that things get real busy.

Hmm... I need to think more about how to handle the start up scenario.

> In general I have found that only a few clients will use events such as:
> IPoIb to manage multicast subscriptions (join as send only for new
> groups) and SA caches/replicas to keep their cache/replica synchronized.

Can you give more details about how ipoib would use the event service?

SA caches seem like they would register for traps... 64 (GID in), 65 (GID out), 
and 128 (switch port change)?  Or is it reasonable to limit it to trap 128?  Is 
trap 128 likely to be followed by traps 64 and 65?

> In the silverstorm stack we created an API for a client to subscribe to
> a notice.  It allowed the client to specify: trap number, local HCA port
> subscription was applicable to (in case multi-port HCAs on different
> fabrics) and information for a callback to the client (client context
> void*, function).  The callback provided the client context void*, the
> actual NOTICE from the SA and which HCA port it arrived on.

This sounds like a simple enough interface.  So, you tracked references on only 
the trap numbers then?

> The API in the stack dealt with all the issues of remaining subscribed
> (SA reregistraton, port disconnected/reconnected, etc) so the client
> merely subscribed, got notice callbacks and later unsubscribed.  In this
> style API any LID based filtering would be done in the client itself.

This makes sense.

- Sean