Date:   Fri, 26 Nov 2021 11:14:31 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= <toke@redhat.com>
Cc:     Alexander Lobakin <alexandr.lobakin@intel.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        "David S. Miller" <davem@davemloft.net>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Michal Swiatkowski <michal.swiatkowski@linux.intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Shay Agroskin <shayagr@amazon.com>,
        Arthur Kiyanovski <akiyano@amazon.com>,
        David Arinzon <darinzon@amazon.com>,
        Noam Dagan <ndagan@amazon.com>,
        Saeed Bishara <saeedb@amazon.com>,
        Ioana Ciornei <ioana.ciornei@nxp.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Marcin Wojtas <mw@semihalf.com>,
        Russell King <linux@armlinux.org.uk>,
        Saeed Mahameed <saeedm@nvidia.com>,
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        Jason Wang <jasowang@redhat.com>,
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        Sergey Ryazanov <ryazanov.s.a@gmail.com>,
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        Andrei Vagin <avagin@gmail.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Cong Wang <cong.wang@bytedance.com>, netdev@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rdma@vger.kernel.org, bpf@vger.kernel.org,
        virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 net-next 21/26] ice: add XDP and XSK generic
 per-channel statistics
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On Fri, 26 Nov 2021 19:47:17 +0100 Toke H=C3=B8iland-J=C3=B8rgensen wrote:
> > Fair. In all honesty I said that hoping to push for a more flexible
> > approach hidden entirely in BPF, and not involving driver changes.
> > Assuming the XDP program has more fine grained stats we should be able
> > to extract those instead of double-counting. Hence my vague "let's work
> > with apps" comment.
> >
> > For example to a person familiar with the workload it'd be useful to
> > know if program returned XDP_DROP because of configured policy or
> > failure to parse a packet. I don't think that sort distinction is
> > achievable at the level of standard stats.
> >
> > The information required by the admin is higher level. As you say the
> > primary concern there is "how many packets did XDP eat". =20
>=20
> Right, sure, I am also totally fine with having only a somewhat
> restricted subset of stats available at the interface level and make
> everything else be BPF-based. I'm hoping we can converge of a common
> understanding of what this "minimal set" should be :)
>=20
> > Speaking of which, one thing that badly needs clarification is our
> > expectation around XDP packets getting counted towards the interface
> > stats. =20
>=20
> Agreed. My immediate thought is that "XDP packets are interface packets"
> but that is certainly not what we do today, so not sure if changing it
> at this point would break things?

I'd vote for taking the risk and trying to align all the drivers.