From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Alexander Lobakin <alexandr.lobakin@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Michal Swiatkowski <michal.swiatkowski@linux.intel.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
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Claudiu Manoil <claudiu.manoil@nxp.com>,
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Subject: Re: [PATCH v2 net-next 00/26] net: introduce and use generic XDP stats
Date: Tue, 30 Nov 2021 17:17:24 +0100 [thread overview]
Message-ID: <871r2x8vor.fsf@toke.dk> (raw)
In-Reply-To: <20211130155612.594688-1-alexandr.lobakin@intel.com>
Alexander Lobakin <alexandr.lobakin@intel.com> writes:
> From: Alexander Lobakin <alexandr.lobakin@intel.com>
> Date: Tue, 23 Nov 2021 17:39:29 +0100
>
> Ok, open questions:
>
> 1. Channels vs queues vs global.
>
> Jakub: no per-channel.
> David (Ahern): it's worth it to separate as Rx/Tx.
> Toke is fine with globals at the end I think?
Well, I don't like throwing data away, so in that sense I do like
per-queue stats, but it's not a very strong preference (i.e., I can live
with either)...
> My point was that for most of the systems we have 1:1 Rx:Tx
> (usually num_online_cpus()), so asking drivers separately for
> the number of RQs and then SQs would end up asking for the same
> number twice.
> But the main reason TBH was that most of the drivers store stats
> on a per-channel basis and I didn't want them to regress in
> functionality. I'm fine with reporting only netdev-wide if
> everyone are.
>
> In case if we keep per-channel: report per-channel only by request
> and cumulative globals by default to not flood the output?
... however if we do go with per-channel stats I do agree that they
shouldn't be in the default output. I guess netlink could still split
them out and iproute2 could just sum them before display?
> 2. Count all errors as "drops" vs separately.
>
> Daniel: account everything as drops, plus errors should be
> reported as exceptions for tracing sub.
> Jesper: we shouldn't mix drops and errors.
>
> My point: we shouldn't, that's why there are patches for 2 drivers
> to give errors a separate counter.
> I provided an option either to report all errors together ('errors'
> in stats structure) or to provide individual counters for each of
> them (sonamed ctrs), but personally prefer detailed errors. However,
> they might "go detailed" under trace_xdp_exception() only, sound
> fine (OTOH in RTNL stats we have both "general" errors and detailed
> error counters).
I agree it would be nice to have a separate error counter, but a single
counter is enough when combined with the tracepoints.
> 3. XDP and XSK ctrs separately or not.
>
> My PoV is that those are two quite different worlds.
> However, stats for actions on XSK really make a little sense since
> 99% of time we have xskmap redirect. So I think it'd be fine to just
> expand stats structure with xsk_{rx,tx}_{packets,bytes} and count
> the rest (actions, errors) together with XDP.
A whole set of separate counters for XSK is certainly overkill. No
strong preference as to whether they need a separate counter at all...
> Rest:
> - don't create a separate `ip` command and report under `-s`;
> - save some RTNL skb space by skipping zeroed counters.
>
> Also, regarding that I count all on the stack and then add to the
> storage once in a polling cycle -- most drivers don't do that and
> just increment the values in the storage directly, but this can be
> less performant for frequently updated stats (or it's just my
> embedded past).
> Re u64 vs u64_stats_t -- the latter is more universal and
> architecture-friendly, the former is used directly in most of the
> drivers primarily because those drivers and the corresponding HW
> are being run on 64-bit systems in the vast majority of cases, and
> Ethtools stats themselves are not so critical to guard them with
> anti-tearing. Anyways, local64_t is cheap on ARM64/x86_64 I guess?
I'm generally a fan of correctness first, so since you're touching all
the drivers anyway why I'd say go for u64_stats_t :)
-Toke
next prev parent reply other threads:[~2021-11-30 16:18 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
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 [this message]
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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