"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote on 11/24/2011 09:44:31 PM: > > As far as I can see, ixgbe binds queues to physical cpu, so let consider: > > > > vhost thread transmits packets of flow A on processor M > > during packet transmission, ixgbe driver programs the card to > > deliver the packet of flow A to queue/cpu M through flow director > > (see ixgbe_atr()) > > vhost thread then receives packet of flow A with from M > > ... > > vhost thread transmits packets of flow A on processor N > > ixgbe driver programs the flow director to change the delivery of > > flow A to queue N ( cpu N ) > > vhost thread then receives packet of flow A with from N > > ... > > > > So, for a single flow A, we may get different queue mappings. Using > > rxhash instead may solve this issue. > > Or better, transmit a single flow from a single vhost thread. > > If packets of a single flow get spread over different CPUs, > they will get reordered and things are not going to work well. My testing so far shows that guest sends on (e.g.) TXQ#2 only, which is handled by vhost#2; and this doesn't change for the entire duration of the test. Incoming keeps changing for different packets but become same with this patch. To iterate, I have not seen the following: " vhost thread transmits packets of flow A on processor M ... vhost thread transmits packets of flow A on processor N " - KK _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
