[ofa-general] Re: multicast join failed for...

[Hal Rosenstock]

On Fri, 2007-04-13 at 09:57, Michael S. Tsirkin wrote:
> > Quoting Hal Rosenstock <halr at voltaire.com>:
> > Subject: Re: [ofa-general] Re: multicast join failed for...
> > 
> > On Fri, 2007-04-13 at 09:38, Michael S. Tsirkin wrote:
> > > > > If the group is created at a lower rate, there would be no problem.
> > > > > But the default configuration should be "plug an play".
> > > > 
> > > > So you are arguing for 1x SDR as the default. We've discussed and
> > > > disagreed on this before as I think it masks performance issues and
> > > > those are harder to find. I could be wrong about this.
> > > 
> > > No, I'm arguing for dynamic configuration as the default.
> > > so we start at 4x DDR and bbring the rate down as slower nodes join.
> > 
> > OK that answers a different question I was wondering about. Or speed it
> > up if all nodes are say 4x DDR.
> > 
> > What I was trying to say was that since we don't have dynamic rate
> > support now (and I'm not signing up to do this, is someone ?),
> 
> I don't know too much about opensm yet, but I can try looking into it,
> or try talking someone into this :)
> 
> But I'm happy we all agree it's a good idea.
> Let's add this to osm/doc/todo?

Sure. I just added this as:
Add dynamic rate adjustment for multicast groups

> > I was
> > saying that a static rate default of 1x SDR would eliminate the join
> > errors (at the debug "expense" of what I think are harder to find
> > performance issues). Sorry I didn't make that clear before.
> 
> I think if we either
> 1. Add an option to disable 1x support at endnode
> or
> 2. Implement a tool to find and report 1x links

We have had this for quite some time.

> or
> 3. By default, report 1x links in opensm log as errors

But not all 1x links are errors.

I also think it may need to go further than this.

> Then this issue will be easy to debug.

Easier but I'm not sure about easy (at least not yet). I think it still
comes down to knowledgable users/admins.

-- Hal