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[209.132.180.67]) by mx.google.com with ESMTP id m18-v6si19780152pgg.693.2018.08.14.02.23.41; Tue, 14 Aug 2018 02:23:55 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731937AbeHNMIs (ORCPT + 99 others); Tue, 14 Aug 2018 08:08:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:42252 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730340AbeHNMIs (ORCPT ); Tue, 14 Aug 2018 08:08:48 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9AFD0F2B36; Tue, 14 Aug 2018 09:22:28 +0000 (UTC) Received: from localhost (ovpn-200-47.brq.redhat.com [10.40.200.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id 53D692026D7E; Tue, 14 Aug 2018 09:22:26 +0000 (UTC) Date: Tue, 14 Aug 2018 11:22:22 +0200 From: Jesper Dangaard Brouer To: Jason Wang Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, mst@redhat.com Subject: Re: [RFC PATCH net-next V2 6/6] virtio-net: support XDP rx handler Message-ID: <20180814112222.42177a24@redhat.com> In-Reply-To: <1534130250-5302-7-git-send-email-jasowang@redhat.com> References: <1534130250-5302-1-git-send-email-jasowang@redhat.com> <1534130250-5302-7-git-send-email-jasowang@redhat.com> Organization: Red Hat Inc. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 14 Aug 2018 09:22:28 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 14 Aug 2018 09:22:28 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jbrouer@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Aug 2018 11:17:30 +0800 Jason Wang 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 > --- > 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