At 06:00 PM 3/20/2006, Sean Hefty wrote: >Can you provide more details on this statement? When are you fencing the send >queue when using memory windows?
Infiniband 101, and VI before it. Memory windows fence later operations on the send queue until the bind completes. It's a misguided attempt to make upper layers' job "easier" because they can post a bind and then immediately post a send carrying the rkey. In reality, it introduces bubbles in the send pipeline and reduces op rates dramatically. I argued against them in iWARP verbs, and lost. If Linux could introduce a way to make the fencing behavior optional, I would lead the parade. I fear most hardware is implemented otherwise. Yes, I know about binding on a separate queue. That doesn't work, because windows are semantically not fungible (for security reasons). Tom. _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
