netdev - RE: [PATCH RFC 0/2] ethtool: Add actual port speed reporting

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Date:   Wed, 2 Nov 2016 15:50:25 +0000
From:   "Mintz, Yuval" <Yuval.Mintz@...ium.com>
To:     Gal Pressman <galp@...lanox.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "John W. Linville" <linville@...driver.com>,
        "Vidya Sagar Ravipati" <vidya@...ulusnetworks.com>,
        Saeed Mahameed <saeedm@...lanox.com>
CC:     David Decotigny <decot@...glers.com>,
        Ben Hutchings <ben@...adent.org.uk>
Subject: RE: [PATCH RFC 0/2] ethtool: Add actual port speed reporting

> Sending RFC to get feedback for the following ethtool proposal:
> 
> In some cases such as virtual machines and multi functions (SR-IOV), the actual
> bandwidth exposed for each machine is not accurately shown in ethtool.
> Currently ethtool shows only physical port link speed.
> In our case we would like to show the virtual port operational link speed which
> in some cases is less than the physical port speed.
> 
> This will give users better visibility for the actual speed running on their device.
> 
> $ ethtool ens6
> ...
> Speed: 50000Mb/s
> Actual speed: 25000Mb/s

Not saying this is a bad thing, but where exactly is it listed that ethtool has
to show the physical port speed?
E.g., bnx2x shows the logical speed instead, and has been doing that for years.
[Perhaps that's a past wrongness, but that's how it goes].

And besides, one can argue that in the SR-IOV scenario the VF has no business
knowing the physical port speed.