[openib-general] basic IB doubt

[Thomas Bachman]

>On Thu, Aug 24, 2006 at 03:13:33PM -0700, Woodruff, Robert J wrote:
>> If the feature gives them a huge advantage in performance (and it
>> does) and all of the hardware vendors that they deal with already
>> implement it, then yes, they will force, by defacto standard that
>> all other newcomers implement it or face the fact that no one will
>> buy their hardware. It seems like that is what is happening in this
>> case.
>
>In this case the feature reduces performance on one HCA and increases
>it on another. Which shows why it's a bad idea to pick features based
>on a single implementation.
>
> But you're still confusing practicality and theory. I can see why it's
> pratical sense for newcomers to implement this new, performance-
> reducing feature. But why is it theoretically good? And shouldn't it
> be added to the standard, before all the poor iWarp people discover
> the hard way that they need it?
>
> -- greg

Not that I have any stance on this issue, but is this is the text in the
spec that is being debated? 

(page 269, section 9.5, Transaction Ordering):
"An application shall not depend upon the order of data writes to
memory within a message. For example, if an application sets up
data buffers that overlap, for separate data segments within a
message, it is not guaranteed that the last sent data will always
overwrite the earlier."

I'm assuming that the spec authors had reason for putting this in there, so
maybe they could provide guidance here?

Or was this only meant to apply to SENDs, and not RDMA WRITEs?

Cheers,

-Thomas Bachman