From: Jakub Kicinski <jakub.kicinski@netronome.com>
To: Prashant Bhole <prashantbhole.linux@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
"Michael S . Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
netdev@vger.kernel.org, qemu-devel@nongnu.org,
kvm@vger.kernel.org
Subject: Re: [RFC net-next 00/18] virtio_net XDP offload
Date: Tue, 26 Nov 2019 12:35:14 -0800 [thread overview]
Message-ID: <20191126123514.3bdf6d6f@cakuba.netronome.com> (raw)
In-Reply-To: <20191126100744.5083-1-prashantbhole.linux@gmail.com>
On Tue, 26 Nov 2019 19:07:26 +0900, Prashant Bhole wrote:
> Note: This RFC has been sent to netdev as well as qemu-devel lists
>
> This series introduces XDP offloading from virtio_net. It is based on
> the following work by Jason Wang:
> https://netdevconf.info/0x13/session.html?xdp-offload-with-virtio-net
>
> Current XDP performance in virtio-net is far from what we can achieve
> on host. Several major factors cause the difference:
> - Cost of virtualization
> - Cost of virtio (populating virtqueue and context switching)
> - Cost of vhost, it needs more optimization
> - Cost of data copy
> Because of above reasons there is a need of offloading XDP program to
> host. This set is an attempt to implement XDP offload from the guest.
This turns the guest kernel into a uAPI proxy.
BPF uAPI calls related to the "offloaded" BPF objects are forwarded
to the hypervisor, they pop up in QEMU which makes the requested call
to the hypervisor kernel. Today it's the Linux kernel tomorrow it may
be someone's proprietary "SmartNIC" implementation.
Why can't those calls be forwarded at the higher layer? Why do they
have to go through the guest kernel?
If kernel performs no significant work (or "adds value", pardon the
expression), and problem can easily be solved otherwise we shouldn't
do the work of maintaining the mechanism.
The approach of kernel generating actual machine code which is then
loaded into a sandbox on the hypervisor/SmartNIC is another story.
I'd appreciate if others could chime in.
next prev parent reply other threads:[~2019-11-26 20:35 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 10:07 [RFC net-next 00/18] virtio_net XDP offload Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 01/18] bpf: introduce bpf_prog_offload_verifier_setup() Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 02/18] net: core: rename netif_receive_generic_xdp() to do_generic_xdp_core() Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 03/18] net: core: export do_xdp_generic_core() Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 04/18] tuntap: check tun_msg_ctl type at necessary places Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 05/18] vhost_net: user tap recvmsg api to access ptr ring Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 06/18] tuntap: remove usage of ptr ring in vhost_net Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 07/18] tun: set offloaded xdp program Prashant Bhole
2019-12-01 16:35 ` David Ahern
2019-12-02 2:44 ` Jason Wang
2019-12-01 16:45 ` David Ahern
2019-12-02 2:47 ` Jason Wang
2019-12-09 0:24 ` Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 08/18] tun: run offloaded XDP program in Tx path Prashant Bhole
2019-12-01 16:39 ` David Ahern
2019-12-01 20:56 ` David Miller
2019-12-01 21:40 ` Michael S. Tsirkin
2019-12-01 21:54 ` David Miller
2019-12-02 2:56 ` Jason Wang
2019-12-02 2:45 ` Jason Wang
2019-11-26 10:07 ` [RFC net-next 09/18] tun: add a way to inject Tx path packet into Rx path Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 10/18] tun: handle XDP_TX action of offloaded program Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 11/18] tun: run xdp prog when tun is read from file interface Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 12/18] virtio-net: store xdp_prog in device Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 13/18] virtio_net: use XDP attachment helpers Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 14/18] virtio_net: add XDP prog offload infrastructure Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 15/18] virtio_net: implement XDP prog offload functionality Prashant Bhole
2019-11-27 20:42 ` Michael S. Tsirkin
2019-11-28 2:53 ` Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 16/18] bpf: export function __bpf_map_get Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 17/18] virtio_net: implment XDP map offload functionality Prashant Bhole
2019-11-26 10:07 ` [RFC net-next 18/18] virtio_net: restrict bpf helper calls from offloaded program Prashant Bhole
2019-11-26 20:35 ` Jakub Kicinski [this message]
2019-11-27 2:59 ` [RFC net-next 00/18] virtio_net XDP offload Jason Wang
2019-11-27 19:49 ` Jakub Kicinski
2019-11-28 3:41 ` Jason Wang
2019-11-27 20:32 ` Michael S. Tsirkin
2019-11-27 23:40 ` Jakub Kicinski
2019-12-02 15:29 ` Michael S. Tsirkin
2019-11-28 3:32 ` Alexei Starovoitov
2019-11-28 4:18 ` Jason Wang
2019-12-01 16:54 ` David Ahern
2019-12-02 2:48 ` Jason Wang
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