[openib-general] Some Missing Features from mthca/user MADaccess

[Sean Hefty]

Hal Rosenstock wrote:
>>On the other hand, attributes mask are much more reasonable. It may
>>allow you to split qp0/qp1 responsibilities to several applications on
>>the same node. This may be applicable to SA attributes. For example, I
>>am not sure why the OpenSM have to manage the service record database.
>>Such attributes mask will enable us to distribute it.
> 
> 
> Filtering on attribute could be done and was argued for back when the
> API was being discussed but the consensus was that we could live without
> it. With attribute filtering, I think you could direct a specific
> attribute to a specific thread easier.

An issue with attribute filtering is that is results in an O(lg n) 
algorithm being used to route MADs to the correct client.  Routing 
based on class/method can be done in O(1), since the range of 
classes/methods is substantially smaller than that of attributes.

Adding an attribute mask isn't overly difficult, it just wasn't felt 
that it was necessary.

- Sean