Den mån 17 dec. 2018 kl 20:40 skrev William Tu <u9012...@gmail.com>: > > The patch series adds AF_XDP async xmit support for veth device. > First patch add a new API for supporting non-physical NIC device to get > packet's virtual address. The second patch implements the async xmit, > and last patch adds example use cases. >
The first virtual device with AF_XDP support! Yay! This is only the zero-copy on the Tx side -- it's still allocations plus copy on the ingress side? That's a bit different from the i40e/ixgbe implementation, where zero-copy means both Tx and Rx. For veth I don't see that we need to support Rx right away, especially for Tx only sockets. Still, when the netdev has accepted the umem via ndo_bpf, the zero-copy for both Tx and Rx is assumed. We might want to change the ndo_bpf at some point to support zero-copy for Tx, Rx, Tx *and* Rx. Are you planning to add zero-copy to the ingress side, i.e. pulling frames from the fill ring, instead of allocating via dev_alloc_page? (The term *zero-copy* for veth is a bit weird, since we're still doing copies, but eliding the page allocation. :-)) It would be interesting to hear a bit about what use-case veth/AF_XDP has, if you can share that. Cheers, Björn > I tested with 2 namespaces, one as sender, the other as receiver. > The packet rate is measure at the receiver side. > ip netns add at_ns0 > ip link add p0 type veth peer name p1 > ip link set p0 netns at_ns0 > ip link set dev p1 up > ip netns exec at_ns0 ip link set dev p0 up > > # receiver > ip netns exec at_ns0 xdp_rxq_info --dev p0 --action XDP_DROP > > # sender with AF_XDP > xdpsock -i p1 -t -N -z > > # or sender without AF_XDP > xdpsock -i p1 -t -S > > Without AF_XDP: 724 Kpps > RXQ stats RXQ:CPU pps issue-pps > rx_queue_index 0:1 724339 0 > rx_queue_index 0:sum 724339 > > With AF_XDP: 1.1 Mpps (with ksoftirqd 100% cpu) > RXQ stats RXQ:CPU pps issue-pps > rx_queue_index 0:3 1188181 0 > rx_queue_index 0:sum 1188181 > > William Tu (3): > xsk: add xsk_umem_consume_tx_virtual. > veth: support AF_XDP. > samples: bpf: add veth AF_XDP example. > > drivers/net/veth.c | 247 > ++++++++++++++++++++++++++++++++++++++++- > include/net/xdp_sock.h | 7 ++ > net/xdp/xsk.c | 24 ++++ > samples/bpf/test_veth_afxdp.sh | 67 +++++++++++ > 4 files changed, 343 insertions(+), 2 deletions(-) > create mode 100755 samples/bpf/test_veth_afxdp.sh > > -- > 2.7.4 >
