From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
To: Ilya Maximets <i.maximets@ovn.org>, netdev@vger.kernel.org
Cc: Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] net: tun: bump the link speed from 10Mbps to 10Gbps
Date: Wed, 2 Nov 2022 14:25:17 +0100 [thread overview]
Message-ID: <39232de9-9497-3a8b-294a-702ed54e273c@6wind.com> (raw)
In-Reply-To: <20221031173953.614577-1-i.maximets@ovn.org>
Le 31/10/2022 à 18:39, Ilya Maximets a écrit :
> The 10Mbps link speed was set in 2004 when the ethtool interface was
> initially added to the tun driver. It might have been a good
> assumption 18 years ago, but CPUs and network stack came a long way
> since then.
>
> Other virtual ports typically report much higher speeds. For example,
> veth reports 10Gbps since its introduction in 2007.
>
> Some userspace applications rely on the current link speed in
> certain situations. For example, Open vSwitch is using link speed
> as an upper bound for QoS configuration if user didn't specify the
> maximum rate. Advertised 10Mbps doesn't match reality in a modern
> world, so users have to always manually override the value with
> something more sensible to avoid configuration issues, e.g. limiting
> the traffic too much. This also creates additional confusion among
> users.
>
> Bump the advertised speed to at least match the veth.
>
> Alternative might be to explicitly report UNKNOWN and let the user
> decide on a right value for them. And it is indeed "the right way"
> of fixing the problem. However, that may cause issues with bonding
> or with some userspace applications that may rely on speed value to
> be reported (even though they should not). Just changing the speed
> value should be a safer option.
>
> Users can still override the speed with ethtool, if necessary.
>
> RFC discussion is linked below.
>
> Link: https://lore.kernel.org/lkml/20221021114921.3705550-1-i.maximets@ovn.org/
> Link: https://mail.openvswitch.org/pipermail/ovs-discuss/2022-July/051958.html
> Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
next prev parent reply other threads:[~2022-11-02 13:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 17:39 [PATCH net-next] net: tun: bump the link speed from 10Mbps to 10Gbps Ilya Maximets
2022-11-02 13:25 ` Nicolas Dichtel [this message]
2022-11-03 8:50 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=39232de9-9497-3a8b-294a-702ed54e273c@6wind.com \
--to=nicolas.dichtel@6wind.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=i.maximets@ovn.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).