Messages in this thread |  | | Date | Tue, 14 Aug 2018 11:22:22 +0200 | From | Jesper Dangaard Brouer <> | Subject | Re: [RFC PATCH net-next V2 6/6] virtio-net: support XDP rx handler |
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On Mon, 13 Aug 2018 11:17:30 +0800 Jason Wang <jasowang@redhat.com> wrote:
> This patch tries to add the support of XDP rx handler to > virtio-net. This is straight-forward, just call xdp_do_pass() and > behave depends on its return value. > > Test was done by using XDP_DROP (xdp1) for macvlan on top of > virtio-net. PPS of SKB mode was ~1.2Mpps while PPS of native XDP mode > was ~2.2Mpps. About 83% improvement was measured.
I'm not convinced...
Why are you not using XDP_REDIRECT, which is already implemented in receive_mergeable (which you modify below).
The macvlan driver just need to implement ndo_xdp_xmit(), and then you can redirect (with XDP prog from physical driver into the guest). It should be much faster...
> Notes: for RFC, only mergeable buffer case was implemented. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/net/virtio_net.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 62311dd..1e22ad9 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -777,6 +777,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > rcu_read_lock(); > xdp_prog = rcu_dereference(rq->xdp_prog); > if (xdp_prog) { > + rx_xdp_handler_result_t ret; > struct xdp_frame *xdpf; > struct page *xdp_page; > struct xdp_buff xdp; > @@ -825,6 +826,15 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > > switch (act) { > case XDP_PASS: > + ret = xdp_do_pass(&xdp); > + if (ret == RX_XDP_HANDLER_DROP) > + goto drop; > + if (ret != RX_XDP_HANDLER_FALLBACK) { > + if (unlikely(xdp_page != page)) > + put_page(page); > + rcu_read_unlock(); > + goto xdp_xmit; > + } > /* recalculate offset to account for any header > * adjustments. Note other cases do not build an > * skb and avoid using offset > @@ -881,6 +891,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > case XDP_ABORTED: > trace_xdp_exception(vi->dev, xdp_prog, act); > /* fall through */ > +drop: > case XDP_DROP: > if (unlikely(xdp_page != page)) > __free_pages(xdp_page, 0);
-- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
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