[ofa-general] [PATCH] opensm: improve multicast re-routing requests processing

[Sasha Khapyorsky]

Hi Hal,

On 18:23 Tue 08 Sep     , Hal Rosenstock wrote:
> On Sun, Sep 6, 2009 at 1:39 PM, Sasha Khapyorsky <sashak at voltaire.com>wrote:
> 
> >
> > When we have two or more changes in a same multicast group multiple
> > multicast rerouting requests will be created and processed. To prevent
> > this we will use array of requests indexed by mlid value minus
> > IB_LID_MCAST_START_HO and for each multicast group change we will just
> > mark that specific mlid requires re-routing and "duplicated" requests
> > will be merged there.
> >
> > Also in this way we will be able to process multicast group routing
> > entries deletion for already removed groups by just knowing its MLID
> > and not using its content - this will let us to not delay mutlicast
> > groups deletion ('to_be_deleted' flag) and will simplify many multicast
> > related code flows.
> >
> 
> While the delay adds complexity, it is a feature. Delayed deletion (and
> join) is allowed by IBA and is needed in a fast changing subnet when there
> are a lot of groups changing. This was seen quite a while ago and was how
> OpenSM evolved based on field experience and other testing. Eitan is the
> expert here. IMO support for this needs to be added (back in).

Maybe my changelog message is unclear (although I don't see this
immediately). This patch does nothing with multicast re-routing
scheduling, but with multicast group object deletion.

Sasha