On Fri, Nov 04, 2005 at 10:19:52AM -0800, Grant Grundler wrote: ... > o The comments in "Recv operations" talk about "backpressure". > Is this another way of saying the driver should drop packets once > the "fairness threshold" is exceeded?
Ranjot's slideset answered this question (I think): | o Slow receiver ports are stalled at sender side | - combination of activity (LRU) and memory utilization used | to detect slow receivers | - sendmsg() to stalled destination port returns | EWOULDBLOCK, application can retry | - recvmsg() on a stalled port un-stalls it I'm having trouble reconciling previous "connectionless" and "transperent to user space" comments this this slide. Especially the "EWOULDBLOCK" return code. If a reciever can cause a sender to stall, it implies the packets will get dropped on the send side. This is a subtle change in behavior that I don't think any UDP application can assume. But I'm no networking protocol expert... thanks, grant _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
