On 22/03/2016 18:38, "Ben Pfaff" <b...@ovn.org> wrote:
>On Wed, Mar 23, 2016 at 01:13:06AM +0000, Daniele Di Proietto wrote: >> >> On 22/03/2016 17:57, "Ben Pfaff" <b...@ovn.org> wrote: >> >> >On Mon, Mar 14, 2016 at 06:18:17PM +0300, Ilya Maximets wrote: >> >> This is unused functionality and it will harm to >> >> multiqueue implementation. >> >> >> >> Signed-off-by: Ilya Maximets <i.maxim...@samsung.com> >> > >> >This change doesn't make any sense to me. An equivalent change to the >> >Linux kernel would mean that if two copies of "tcpdump -i eth0" were >> >running then only one of them would get any packets. >> >> I independently decided to make a very similar code change with the >> same semantics to netdev-dummy, so maybe there's something I don't >> understand as well :-) >> >> netdev-dummy is like a physical NIC, the wire is a stream object >> (or the netdev-dummy/receive appctl, but only in one direction). >> >> When a multi queue NIC receives a packet from the wire it should >> put it in just one of its rings, right? > >I don't understand the confusion. > >Suppose I call netdev_rxq_open() on a netdev that's backed by >netdev-linux, say for eth0. That calls into >netdev_linux_rxq_construct(), which opens a Linux AF_PACKET socket. >From then on, I can call netdev_rxq_recv() on the netdev_rxq that I got >(call it rxq0), and get a copy of each packet received on eth0. > >Suppose I call netdev_rxq_open() on the same netdev again. I get an >independent netdev_rxq socket for eth0 (call it rxq1). I can call >netdev_rxq_recv() on both rxq0 and rxq1 and I'll get two copies of the >same stream of packets. > >netdev-dummy is implementing the same thing. struct netdev_dummy has a >list of open "netdev_rxq"s as its member named 'rxes'. Each of those >gets a copy of all the received packets. > >So...am I missing something? Oh, I see, I didn't consider this use case at all. Currently netdev-dpdk doesn't support this and it assumes that there will be only one open rxq per queue_id. The only user of rxqs is dpif-netdev and it is just opening one rxq per queue_id. I'm not sure it's necessary to support multiple receivers for the same packets, but I'm open to suggestions. I guess, at least, I'll need to document the current interface better. What do you think? _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
