Subject: Re: [Patch RFC net-next] net: usb: r8152: Fix rx_bytes/tx_bytes to include FCS

From: Andrew Lunn <[email-masked]>
Date: Thu, 18 May 2017 19:33:39 +0200

Hi Florian

I agree we should define this, and we can add it to
Documentation/ABI/testing/sysfs-class-net-statistics

> - BQL cares about bytes sent on the wire, so that should not include
> pre/appended descriptors nor the FCS (nor the Ethernet preamble),
> tx_bytes should be equivalent to that

Can you point me at some documentation/code which shows this?

pre/appended descriptors i can understand, since it does not make it
to the wire. FCS does. Preamble and inter-frame gap also does make it
to the wire, and contributes to the overall load on the medium. But i
would expect BQL is tolerant to this. We are talking about an error of
about 0.26% for a full MTU frame if FCS is included when it should not
be.

If BQL really does care about not including the FCS, we probably have
a lot less to do. People should of audited their code when they added
support for BQL :-)

    Andrew