[ofa-general] Default multicast group rate

[Eitan Zahavi]

I agree with Sasha.
Administrator needs to configure the SM to assign the lowest allowed
rate.
All the rest is beyond the spec. Might be a good idea but not very
practical until spec'd.

Eitan Zahavi


> -----Original Message-----
> From: general-bounces at lists.openfabrics.org [mailto:general-
> bounces at lists.openfabrics.org] On Behalf Of Sasha Khapyorsky
> Sent: Friday, April 13, 2007 6:41 PM
> To: Hal Rosenstock
> Cc: general at lists.openfabrics.org
> Subject: Re: [ofa-general] Default multicast group rate
> 
> On 07:44 Fri 13 Apr     , Hal Rosenstock wrote:
> > Hi,
> >
> > There has been a lot of discussion over the last week on failed
> > multicast joins.
> >
> > The current default rate for multicast groups is 10 Gbps. This means
> > that slower nodes (whether due to 1x SDR equipment or a degraded
link)
> > will fail the join.
> >
> > The current default was chosen in the belief that most installations
> > would be 4x SDR equipment or better (the most common use case)
rather
> > than the lowest common denominator use case. Also, choosing a lower
> > default affects preformance of all multicast groups (which includes
the
> > IPv4 broadcast group as well as any other derived groups (not just
IPoIB
> > multicast groups)). So when certain performance tests are run, this
will
> > be a factor which needs to be investigated. The thinking was that
those
> > subtle things are harder (but perhaps less frequent) to find than
the
> > "harder" join error which forces the admin to decide one way or the
> > other so there is no masking this.
> >
> > So the question is whether the best default is 2.5 Gbps which would
> > allow any nodes to join or whether the current default is
appropriate ?
> > I know certain people's opinions who have been vocal on this list up
to
> > now. I'm looking for other opinions. Thanks.
> 
> This value is configurable, and 10Gs/s as default looks reasonable
> for me.
> 
> Sasha
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