From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: mst@redhat.com, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
john.fastabend@gmail.com, brouer@redhat.com
Subject: Re: [PATCH net-next 2/2] virtio-net: simplify XDP handling in small buffer
Date: Thu, 1 Mar 2018 10:15:53 +0100 [thread overview]
Message-ID: <20180301101553.55c4c6bd@redhat.com> (raw)
In-Reply-To: <dbbfd899-fb7e-c039-5c9a-0f3b6ce34b78@redhat.com>
On Thu, 1 Mar 2018 16:49:24 +0800
Jason Wang <jasowang@redhat.com> wrote:
> > 2. This can easily cause out-of-order packets.
>
> I may miss something, but it looks to me packets were still delivered
> in order? Or you mean the packets that was dropped by cpumap?
No. Packets can now travel two code paths to the egress device. (1) XDP
native via ndp_xdp_xmit via direct delivery into a lockfree/dedicated
TX queue, (2) via normal network stack which can involve being queue in
a qdisc. Do you see the possibility of the reorder now?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
WARNING: multiple messages have this Message-ID (diff)
From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: mst@redhat.com, netdev@vger.kernel.org, john.fastabend@gmail.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, brouer@redhat.com
Subject: Re: [PATCH net-next 2/2] virtio-net: simplify XDP handling in small buffer
Date: Thu, 1 Mar 2018 10:15:53 +0100 [thread overview]
Message-ID: <20180301101553.55c4c6bd@redhat.com> (raw)
In-Reply-To: <dbbfd899-fb7e-c039-5c9a-0f3b6ce34b78@redhat.com>
On Thu, 1 Mar 2018 16:49:24 +0800
Jason Wang <jasowang@redhat.com> wrote:
> > 2. This can easily cause out-of-order packets.
>
> I may miss something, but it looks to me packets were still delivered
> in order? Or you mean the packets that was dropped by cpumap?
No. Packets can now travel two code paths to the egress device. (1) XDP
native via ndp_xdp_xmit via direct delivery into a lockfree/dedicated
TX queue, (2) via normal network stack which can involve being queue in
a qdisc. Do you see the possibility of the reorder now?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2018-03-01 9:16 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 3:19 [PATCH net-next 0/2] virtio-net: re enable XDP_REDIRECT for mergeable buffer Jason Wang
2018-03-01 3:19 ` Jason Wang
2018-03-01 3:19 ` [PATCH net-next 1/2] " Jason Wang
2018-03-01 3:19 ` Jason Wang
2018-03-01 8:41 ` Jesper Dangaard Brouer
2018-03-01 8:41 ` Jesper Dangaard Brouer
2018-03-01 9:11 ` Jason Wang
2018-03-01 9:11 ` Jason Wang
2018-03-01 13:36 ` Michael S. Tsirkin
2018-03-01 13:36 ` Michael S. Tsirkin
2018-03-02 4:20 ` Jason Wang
2018-03-02 4:20 ` Jason Wang
2018-03-01 3:19 ` [PATCH net-next 2/2] virtio-net: simplify XDP handling in small buffer Jason Wang
2018-03-01 8:02 ` Jesper Dangaard Brouer
2018-03-01 8:02 ` Jesper Dangaard Brouer
2018-03-01 8:49 ` Jason Wang
2018-03-01 9:15 ` Jesper Dangaard Brouer [this message]
2018-03-01 9:15 ` Jesper Dangaard Brouer
2018-03-01 9:24 ` Jason Wang
2018-03-01 9:24 ` Jason Wang
2018-03-01 8:49 ` Jason Wang
2018-03-01 3:19 ` Jason Wang
2018-03-01 9:10 ` [PATCH net-next 0/2] virtio-net: re enable XDP_REDIRECT for mergeable buffer Jesper Dangaard Brouer
2018-03-01 9:10 ` Jesper Dangaard Brouer
2018-03-01 9:23 ` Jason Wang
2018-03-01 9:23 ` Jason Wang
2018-03-01 10:35 ` Jesper Dangaard Brouer
2018-03-01 10:35 ` Jesper Dangaard Brouer
2018-03-01 13:15 ` Jason Wang
2018-03-01 14:16 ` Jesper Dangaard Brouer
2018-03-01 14:16 ` Jesper Dangaard Brouer
2018-03-02 4:17 ` Jason Wang
2018-03-02 4:17 ` Jason Wang
2018-03-01 13:15 ` Jason Wang
2018-03-01 13:40 ` Michael S. Tsirkin
2018-03-01 13:40 ` Michael S. Tsirkin
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