From: Tobias Waldekranz <tobias@waldekranz.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Vladimir Oltean <olteanv@gmail.com>,
davem@davemloft.net, kuba@kernel.org, vivien.didelot@gmail.com,
f.fainelli@gmail.com, j.vosburgh@gmail.com, vfalico@gmail.com,
andy@greyhouse.net, netdev@vger.kernel.org
Subject: Re: [PATCH v3 net-next 2/4] net: dsa: Link aggregation support
Date: Thu, 03 Dec 2020 22:35:12 +0100 [thread overview]
Message-ID: <877dpy7eun.fsf@waldekranz.com> (raw)
In-Reply-To: <20201203210941.GJ2333853@lunn.ch>
On Thu, Dec 03, 2020 at 22:09, Andrew Lunn <andrew@lunn.ch> wrote:
>> One could argue that if Linus had received an error instead, adapted his
>> teamd config and tried again, he would be a happier user and we might
>> not have to compete with his OS.
>>
>> I am not sure which way is the correct one, but I do not think that it
>> necessarily _always_ correct to silently fallback to a non-offloaded
>> mode.
>
> This is an argument Mellanox makes, where falling back to software
> would be a bad idea given the huge bandwidth of their hardware
> accelerator, and the slow bandwidth of their CPU.
Yeah when you have 100G interfaces the choice becomes easier :)
> If the switch has no hardware support for LAG at all, then falling
> back to software is reasonable. It is less clear when there is some
> support in the switch. If we do reject it, we should try to make use
> of extack to give the user a useful error messages: Not supported, try
> configuration XYZ. But i guess that needs some plumbing, getting
> extack available in the place we make the decision.
I do not think we need to add anything. Looking at mlxsw, the extack is
available in the `struct netdev_notifier_changeupper_info`.
I am leaning towards the behavior you just described:
- If there is no offloading available, accept anything and let the
software take care of it. The user wants a LAG and that is the best we
can do.
- If offloading is available, reject anything that can not be
offloaded. My guess is that _any_ hardware offloaded setup will almost
always yield a better solution for the user than a software fallback.
next prev parent reply other threads:[~2020-12-03 21:36 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 9:13 [PATCH v3 net-next 0/4] net: dsa: Link aggregation support Tobias Waldekranz
2020-12-02 9:13 ` [PATCH v3 net-next 1/4] net: bonding: Notify ports about their initial state Tobias Waldekranz
2020-12-02 19:09 ` Jay Vosburgh
2020-12-02 21:52 ` Tobias Waldekranz
2020-12-03 0:39 ` Jay Vosburgh
2020-12-03 8:16 ` Tobias Waldekranz
2020-12-02 9:13 ` [PATCH v3 net-next 2/4] net: dsa: Link aggregation support Tobias Waldekranz
2020-12-02 10:07 ` Vladimir Oltean
2020-12-02 10:51 ` Tobias Waldekranz
2020-12-02 18:58 ` Jakub Kicinski
2020-12-02 21:29 ` Tobias Waldekranz
2020-12-02 21:32 ` Vladimir Oltean
2020-12-03 16:24 ` Vladimir Oltean
2020-12-03 20:53 ` Tobias Waldekranz
2020-12-03 21:09 ` Andrew Lunn
2020-12-03 21:35 ` Tobias Waldekranz [this message]
2020-12-04 0:35 ` Vladimir Oltean
2020-12-03 21:57 ` Vladimir Oltean
2020-12-03 23:12 ` Tobias Waldekranz
2020-12-04 0:56 ` Vladimir Oltean
2020-12-07 21:49 ` Tobias Waldekranz
2020-12-04 1:33 ` Andrew Lunn
2020-12-04 4:18 ` Florian Fainelli
2020-12-07 21:56 ` Tobias Waldekranz
2020-12-03 20:48 ` Vladimir Oltean
2020-12-04 2:20 ` Andrew Lunn
2020-12-07 21:19 ` Tobias Waldekranz
2020-12-07 23:26 ` Andrew Lunn
2020-12-09 8:57 ` Tobias Waldekranz
2020-12-09 14:27 ` Andrew Lunn
2020-12-09 15:21 ` Tobias Waldekranz
2020-12-09 23:03 ` Andrew Lunn
2020-12-04 4:04 ` Florian Fainelli
2020-12-08 11:23 ` Vladimir Oltean
2020-12-08 15:33 ` Tobias Waldekranz
2020-12-08 16:37 ` Vladimir Oltean
2020-12-09 8:37 ` Tobias Waldekranz
2020-12-09 10:53 ` Vladimir Oltean
2020-12-09 14:11 ` Tobias Waldekranz
2020-12-09 16:04 ` Vladimir Oltean
2020-12-09 22:01 ` Tobias Waldekranz
2020-12-09 22:21 ` Vladimir Oltean
2020-12-10 10:18 ` Tobias Waldekranz
2020-12-09 22:59 ` Andrew Lunn
2020-12-10 1:05 ` Vladimir Oltean
2020-12-09 14:23 ` Andrew Lunn
2020-12-09 23:17 ` Vladimir Oltean
2020-12-08 17:26 ` Andrew Lunn
2020-12-11 20:50 ` Tobias Waldekranz
2020-12-12 14:26 ` Vladimir Oltean
2020-12-13 21:18 ` Tobias Waldekranz
2020-12-14 0:12 ` Vladimir Oltean
2020-12-14 11:42 ` Ido Schimmel
2020-12-16 15:15 ` Tobias Waldekranz
2020-12-16 18:48 ` Ido Schimmel
2020-12-14 9:41 ` Tobias Waldekranz
2020-12-02 9:13 ` [PATCH v3 net-next 3/4] net: dsa: mv88e6xxx: " Tobias Waldekranz
2020-12-02 9:13 ` [PATCH v3 net-next 4/4] net: dsa: tag_dsa: Support reception of packets from LAG devices Tobias Waldekranz
2020-12-04 3:58 ` Florian Fainelli
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