[ofw] winverbs ND provider

[Fab Tillier]

Hi Tzachi

Tzachi Dar wrote on Wed, 13 Jan 2010 at 09:48:51
> Just making sure, we are talking about 2008 64 bits right?
> 
> 
> As for  QueryPerformanceCounter():
> 
> I have run a simple test routine and I get 1.2 us which is outrageous in
> itself but still very far from your numbers.

This is fixed in Server 2008 R2.

> As for the ibat resolve:
> 
> I have created a very simple "resolve" program and started playing with
> it. Without any change resolve takes ~33us
> 
> I have changed the resolve code to open the ibat device once and than
> only do the resolve many times this took ~27us. I guess that the nd code
> can do a similar thing.

When does the file get closed?  How do you get the application to close the file if, say, IPoIB gets disabled?  Say you have a service that keeps track of IP address arrival/removal, so that it's not necessarily doing anything over IB when IPoIB is disabled.  How do you trigger the service to close the IBAT device?

So while you might be able to save 5us by avoiding opening the file, you introduce issues that aren't worth the benefits.  I'm sure you'd be able to shave off 5us, if not more, by making the QP modify asynchronous.

-Fab