From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Daniel Borkmann <daniel@iogearbox.net>, Jakub Kicinski <kuba@kernel.org>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>,
"David S. Miller" <davem@davemloft.net>,
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Subject: Re: [PATCH v2 net-next 21/26] ice: add XDP and XSK generic per-channel statistics
Date: Mon, 29 Nov 2021 12:51:26 +0100 [thread overview]
Message-ID: <878rx79o3l.fsf@toke.dk> (raw)
In-Reply-To: <871ae82a-3d5b-2693-2f77-7c86d725a056@iogearbox.net>
Daniel Borkmann <daniel@iogearbox.net> writes:
> On 11/26/21 7:06 PM, Jakub Kicinski wrote:
>> On Fri, 26 Nov 2021 13:30:16 +0100 Toke Høiland-Jørgensen wrote:
>>>>> TBH I wasn't following this thread too closely since I saw Daniel
>>>>> nacked it already. I do prefer rtnl xstats, I'd just report them
>>>>> in -s if they are non-zero. But doesn't sound like we have an agreement
>>>>> whether they should exist or not.
>>>>
>>>> Right, just -s is fine, if we drop the per-channel approach.
>>>
>>> I agree that adding them to -s is fine (and that resolves my "no one
>>> will find them" complain as well). If it crowds the output we could also
>>> default to only output'ing a subset, and have the more detailed
>>> statistics hidden behind a verbose switch (or even just in the JSON
>>> output)?
>>>
>>>>> Can we think of an approach which would make cloudflare and cilium
>>>>> happy? Feels like we're trying to make the slightly hypothetical
>>>>> admin happy while ignoring objections of very real users.
>>>>
>>>> The initial idea was to only uniform the drivers. But in general
>>>> you are right, 10 drivers having something doesn't mean it's
>>>> something good.
>>>
>>> I don't think it's accurate to call the admin use case "hypothetical".
>>> We're expending a significant effort explaining to people that XDP can
>>> "eat" your packets, and not having any standard statistics makes this
>>> way harder. We should absolutely cater to our "early adopters", but if
>>> we want XDP to see wider adoption, making it "less weird" is critical!
>>
>> 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.
>
> Agree on the additional context. How often have you looked at tc clsact
> /dropped/ stats specifically when you debug a more complex BPF program
> there?
>
> # tc -s qdisc show clsact dev foo
> qdisc clsact ffff: parent ffff:fff1
> Sent 6800 bytes 120 pkt (dropped 0, overlimits 0 requeues 0)
> backlog 0b 0p requeues 0
>
> Similarly, XDP_PASS counters may be of limited use as well for same reason
> (and I think we might not even have a tc counter equivalent for it).
>
>> The information required by the admin is higher level. As you say the
>> primary concern there is "how many packets did XDP eat".
>
> Agree. Above said, for XDP_DROP I would see one use case where you compare
> different drivers or bond vs no bond as we did in the past in [0] when
> testing against a packet generator (although I don't see bond driver covered
> in this series here yet where it aggregates the XDP stats from all bond slave
> devs).
>
> On a higher-level wrt "how many packets did XDP eat", it would make sense
> to have the stats for successful XDP_{TX,REDIRECT} given these are out
> of reach from a BPF prog PoV - we can only count there how many times we
> returned with XDP_TX but not whether the pkt /successfully made it/.
>
> In terms of error cases, could we just standardize all drivers on the behavior
> of e.g. mlx5e_xdp_handle(), meaning, a failure from XDP_{TX,REDIRECT} will
> hit the trace_xdp_exception() and then fallthrough to bump a drop counter
> (same as we bump in XDP_DROP then). So the drop counter will account for
> program drops but also driver-related drops.
>
> At some later point the trace_xdp_exception() could be extended with an error
> code that the driver would propagate (given some of them look quite similar
> across drivers, fwiw), and then whoever wants to do further processing with
> them can do so via bpftrace or other tooling.
>
> So overall wrt this series: from the lrstats we'd be /dropping/ the pass,
> tx_errors, redirect_errors, invalid, aborted counters. And we'd be /keeping/
> bytes & packets counters that XDP sees, (driver-)successful tx & redirect
> counters as well as drop counter. Also, XDP bytes & packets counters should
> not be counted twice wrt ethtool stats.
This sounds reasonable to me, and I also like the error code to
tracepoint idea :)
-Toke
next prev parent reply other threads:[~2021-11-29 11:53 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 16:39 [PATCH v2 net-next 00/26] net: introduce and use generic XDP stats Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 01/26] rtnetlink: introduce generic XDP statistics Alexander Lobakin
2021-11-30 2:36 ` David Ahern
2021-11-23 16:39 ` [PATCH v2 net-next 02/26] xdp: provide common driver helpers for implementing XDP stats Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 03/26] ena: implement generic XDP statistics callbacks Alexander Lobakin
2021-11-29 13:34 ` Shay Agroskin
2021-11-30 19:14 ` Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 04/26] dpaa2: implement generic XDP stats callbacks Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 05/26] enetc: " Alexander Lobakin
2021-11-23 17:09 ` Vladimir Oltean
2021-11-24 11:37 ` Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 06/26] mvneta: reformat mvneta_netdev_ops Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 07/26] mvneta: add .ndo_get_xdp_stats() callback Alexander Lobakin
2021-11-24 11:39 ` Russell King (Oracle)
2021-11-25 17:16 ` Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 08/26] mvpp2: provide " Alexander Lobakin
2021-11-24 11:33 ` Russell King (Oracle)
2021-11-24 11:36 ` Russell King (Oracle)
2021-11-23 16:39 ` [PATCH v2 net-next 09/26] mlx5: don't mix XDP_DROP and Rx XDP error cases Alexander Lobakin
2021-11-24 18:15 ` kernel test robot
2021-11-25 16:40 ` Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 10/26] mlx5: provide generic XDP stats callbacks Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 11/26] sf100, sfx: implement " Alexander Lobakin
2021-11-24 9:59 ` Edward Cree
2021-11-23 16:39 ` [PATCH v2 net-next 12/26] veth: don't mix XDP_DROP counter with Rx XDP errors Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 13/26] veth: drop 'xdp_' suffix from packets and bytes stats Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 14/26] veth: reformat veth_netdev_ops Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 15/26] veth: add generic XDP stats callbacks Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 16/26] virtio_net: don't mix XDP_DROP counter with Rx XDP errors Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 17/26] virtio_net: rename xdp_tx{,_drops} SQ stats to xdp_xmit{,_errors} Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 18/26] virtio_net: reformat virtnet_netdev Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 19/26] virtio_net: add callbacks for generic XDP stats Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 20/26] i40e: add XDP and XSK generic per-channel statistics Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 21/26] ice: " Alexander Lobakin
2021-11-24 0:52 ` Daniel Borkmann
2021-11-24 16:34 ` Lorenz Bauer
2021-11-25 11:56 ` Toke Høiland-Jørgensen
2021-11-25 17:07 ` Alexander Lobakin
2021-11-25 17:44 ` Jakub Kicinski
2021-11-25 20:40 ` Alexander Lobakin
2021-11-26 12:30 ` Toke Høiland-Jørgensen
2021-11-26 18:06 ` Jakub Kicinski
2021-11-26 18:47 ` Toke Høiland-Jørgensen
2021-11-26 19:14 ` Jakub Kicinski
2021-11-28 17:54 ` Ido Schimmel
2021-11-29 14:47 ` Jakub Kicinski
2021-11-29 15:51 ` Petr Machata
2021-11-29 15:54 ` Petr Machata
2021-11-29 16:05 ` Jakub Kicinski
2021-11-29 17:08 ` Petr Machata
2021-11-29 17:17 ` Jakub Kicinski
2021-11-30 11:55 ` Petr Machata
2021-11-30 15:07 ` Jakub Kicinski
2021-11-26 22:27 ` Daniel Borkmann
2021-11-26 23:01 ` Daniel Borkmann
2021-11-29 13:59 ` Jesper Dangaard Brouer
2021-11-29 15:03 ` Jakub Kicinski
2021-11-29 11:51 ` Toke Høiland-Jørgensen [this message]
2021-11-23 16:39 ` [PATCH v2 net-next 22/26] igb: add XDP " Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 23/26] igc: bail out early on XSK xmit if no descs are available Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 24/26] igc: add XDP and XSK generic per-channel statistics Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 25/26] ixgbe: " Alexander Lobakin
2021-11-23 16:39 ` [PATCH v2 net-next 26/26] Documentation: reflect generic XDP statistics Alexander Lobakin
2021-11-28 22:23 ` [PATCH v2 net-next 00/26] net: introduce and use generic XDP stats David Ahern
2021-11-30 15:56 ` Alexander Lobakin
2021-11-30 16:12 ` Jakub Kicinski
2021-11-30 16:34 ` Alexander Lobakin
2021-11-30 17:04 ` Jakub Kicinski
2021-11-30 17:38 ` David Ahern
2021-11-30 19:46 ` Jakub Kicinski
2021-12-01 15:21 ` Jamal Hadi Salim
2021-11-30 16:17 ` Toke Høiland-Jørgensen
2021-11-30 17:07 ` Jakub Kicinski
2021-11-30 17:56 ` David Ahern
2021-11-30 19:53 ` Jakub Kicinski
2021-11-30 17:45 ` David Ahern
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