[openib-general] Re: [PATCH] Disregard subn->min_ca_rate/mtu during MCGroupcreation.

[Sasha Khapyorsky]

On 11:48 Thu 23 Mar     , Hal Rosenstock wrote:
> > > But is that field set to the max rate/MTU ? (I didn't check the code for
> > > this). Is it just a name thing or more ?
> > 
> > This is more then just name. Currently we only have min_ca_rate which
> > stores value of slowest port's rate. What we will need is similar
> > variable for fastest port's rate, and then to check against it. I like
> > this idea and this should be easy enouph to  do.
> 
> As the max rate/MTU port on the subnet can change, is this worth it ?

This is true, this may change (the same is for min rate/MTU).

Then there may be just basic range check like this:

 if (rate_required < IB_MIN_RATE || rate_required > IB_MAX_RATE)
   error...;

But it is likely useless - later we are checking port's physical
capability to support such rate).

> The realizability is when the port joins not when the group is created.
> This is significant for the precreated groups (as other groups are
> created when the first port joins).
> 
> Is min rate/MTU needed for anything ?

Currently it is used when the rate is not requested.

Also for cases when the rate is requested as greater than specified value.
There is such check: if (rate_requested >= min_ca_rate) error... -  the
same problem I think.

Sasha.