Messages in this thread | | | Date | Wed, 2 Nov 2022 14:25:17 +0100 | Subject | Re: [PATCH net-next] net: tun: bump the link speed from 10Mbps to 10Gbps | From | Nicolas Dichtel <> |
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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>
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