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

[Michael S. Tsirkin]

> > 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.

> > > ipoib multicast performance doesn't seem that critical.
> > 
> > This is a policy than can be made optional, but should not
> > be forced on users by default.
> > 
> > > Whereas disrupting
> > > other multicast groups, which could actively be in use by MPI, may be. 
> > 
> > The disruption would be very minor - this would happen at most once when rate changes
> > from DDR to SDR and once when it changes back.
> 
> In frequency it may be minor. It affects other things that should not be
> affected. Perhaps that is just a shortcoming of the mechanism underneath
> and that can/should be improved.

Yes, I agree.


-- 
MST