Subject: Ready receive.

From: [email-masked] (Jon Flower)
Date: Tue, 6 Apr 93 12:57:53 PDT

While I tend to agree that implementing ready-receive might well improve
the performance of many vendors systems I would like to make the
following observations which relate to my continued voting against
this idea:

    a) I don't believe that vendors will actually go to the trouble
       of implementing this. All the discussions we've had in Dallas
       keep coming back to the "feature" of allowing ready-receive
       which is that it can actually be a no-op. To my mind this
       implies that vendors will take this approach wherever possible.
       (As suggested by Peter -- thank you Peter!!)

    b) If the best that can be expected from this is a 20% improvement
       in communication speed I (personally) don't care very much. I
       don't think that such an improvement is worth fighting for, 
       especially since it only means a tiny overall improvement in 
       an "efficient" program.

Of these two I think point a) is where I have the biggest problem. Why
add a feature to MPI that those outside our meetings might expect to
be implemented, when we know, in our hearts, that it probably isn't 
going to be? At best it's misleading and at worst someone will go
out of their way to use it (by re-ordering their communication
logic, for example) only to find that it doesn't help!.

I think this is the classic case of an "optional" feature that should
be pushed to the back of the manual and left in peace.

Jon