[openib-general] basic IB doubt

[Fabian Tillier]

On 8/24/06, Woodruff, Robert J <robert.j.woodruff at intel.com> 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.

Actually, if a hardware implementation provided the same performance
(in this case latency) by polling on a CQ as one where polling on
memory was garanteed to work, the customer may actually prefer the
"standard" implementation.

If the CQ entry could be updated faster than it is today, then polling
the CQ would be a viable not to mention IB and iWARP standard
solution.  The problem is there's a considerable delay from when the
last byte of data is written to when the CQE is written.  My last
measurement was 2us using a Mellanox PCI-X device.

- Fab