[openib-general] basic IB doubt

[Sean Hefty]

>We're trying to create *inter-operable* hardware and
>software in this community. So we follow the IB standard.

Atomic operations and RDD are optional, yet still part of the IB "standard".  An
application that makes use of either of these isn't guaranteed to operate with
all IB hardware.  I'm not even sure that CAs are required to implement RDMA
reads.

>> It's up to the application to verify that the hardware that they're
>> using provides the required features, or adjust accordingly, and
>> publish those requirements to the end users.
>
>If that was being done (and it isn't), it would still be bad for the
>ecosystem as a whole.

Applications should drive the requirements.  Some poll on memory today.  A lot
of existing hardware provides support for this by guaranteeing that the last
byte will always be written last.  This doesn't mean that data cannot be placed
out of order, only that the last byte is deferred.

Again, if a vendor wants to work with applications written this way, then this
is a feature that should be provided.  If a vendor doesn't care about working
with those applications, or wants to require that the apps be rewritten, then
this feature isn't important.

But I do not see an issue with a vendor adding value beyond what's defined in
the spec.

- Sean