[chord] a philosophical worry...

[Emil Sit]

> if we want to implement such as location cache later so it works
> when number of nodes is larger than nsucc, i think it should be in the

the only concern (as before) would be to ensure that there is a
way to disable all the "small network" optimizations so that we
can (hopefully) get a picture of how the system would behave when
it is larger, even if we can only have a couple of hundred vnodes
running on our current wide-area testbeds.

in some vague philosophical sense, it would be nice not to put a lot
of optimizations into the code (i.e. complicating the code) to deal with
cases when there are fewer than 16 nodes in the system.  as we've
discussed, it doesn't seem like chord is the Right Thing for a 4 node
system, you know?

btw, i'm happy that you put the helper functions as static functions
instead of increasing the number of private functions in the class,
but it seems a little odd to put it in a header file.

> also, it makes vivaldi look better, because i can skip routing and 
> immediately pick a good successor to use in dhash. it used to be 
> that vivaldi wouldn't give you as much benefit because the get 
> successor call sometimes would go to a far away node.

well. really, vivaldi is giving you the same benefit as before.
it's just that you are no longer incurring the cost of doing
a lookup.

-- 
Emil Sit / MIT LCS PDOS / http://pdos.lcs.mit.edu/chord/