The performance of IIOPInputStream.simpleReadObject is
some 3x slower in GF 3.1 v GF 3 in client-side profiles.
In V3, that just calls IIOPInputStream.inputObject().
In V3.1, that spends a little more than half its time in inputObject(),
and the other large part of its time in inputObjectUsingFVD(). V3 and
V3.1 do spend the same amount of time in useFullValueDescription() (a
pretty small amount in either case).
So it seems that for whatever reason, we are using the FVD in 3.1 and
not in V3, and that is really slowing us down. We need either a way to
turn of FVD or to improve the performance of that path.
The performance of inputObject() itself also seems to have regressed,
but I think that's because inputObjectUsingFVD() calls it; once we get
recursive calls, it's hard to tell from the profile.