[ofa-general] Re: [PATCH] ib/ipoib: Reduce comparison size in data path

[Roland Dreier]

 > In the majority of cases, if the neighbour will change, it will
 > be reflected in the guid part of the GID (bytes 8-15). If the GID
 > prefix will change as well (bytes 0-7) it will be because the master
 > SM has changed, in which case we will get an SM change event resulting
 > in all paths flushed.

Is it guaranteed that an active SM can't change a GID prefix?
Especially if we're using a GID at an index != 0?  In other words, is
this change definitely 100 percent safe?

Also I assume this change is coming from performance tuning.  For
patches like this it is always helpful to include hard data like "this
gives a speedup of X on test Y on system Z."

Thanks...