Arnd Bergmann <arnd@xxxxxxxx> wrote on 10/06/2010 05:49:00 PM: > > I don't see any reasons mentioned above. However, for higher > > number of netperf sessions, I see a big increase in retransmissions: > > _______________________________________ > > #netperf ORG NEW > > BW (#retr) BW (#retr) > > _______________________________________ > > 1 70244 (0) 64102 (0) > > 4 21421 (0) 36570 (416) > > 8 21746 (0) 38604 (148) > > 16 21783 (0) 40632 (464) > > 32 22677 (0) 37163 (1053) > > 64 23648 (4) 36449 (2197) > > 128 23251 (2) 31676 (3185) > > _______________________________________ > > > This smells like it could be related to a problem that Ben Greear found > recently (see "macvlan: Enable qdisc backoff logic"). When the hardware > is busy, used to just drop the packet. With Ben's patch, we return -EAGAIN > to qemu (or vhost-net) to trigger a resend. > > I suppose what we really should do is feed that condition back to the > guest network stack and implement the backoff in there. Thanks for the pointer. I will take a look at this as I hadn't seen this patch earlier. Is there any way to figure out if this is the issue? Thanks, - KK -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
