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Date:      Thu, 17 Nov 2011 13:39:24 -0800
From:      Juli Mallett <jmallett@FreeBSD.org>
To:        Maksim Yevmenkin <maksim.yevmenkin@gmail.com>
Cc:        freebsd-net <freebsd-net@freebsd.org>
Subject:   Re: confused with if_baudrate
Message-ID:  <CACVs6=_HOGNhc84hL7yN1NxmS%2BEO5ykEQhOAQuBvjiyxe9JPrg@mail.gmail.com>
In-Reply-To: <CAFPOs6oVZ-%2B8%2B37SoDQmSawAOYnZBAQbLstPaJ5i3wScd8WVeQ@mail.gmail.com>
References:  <CAFPOs6oVZ-%2B8%2B37SoDQmSawAOYnZBAQbLstPaJ5i3wScd8WVeQ@mail.gmail.com>

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On Thu, Nov 17, 2011 at 13:12, Maksim Yevmenkin
<maksim.yevmenkin@gmail.com> wrote:
> hello,
>
> i'm a little bit confused about if_baudrate. from system headers
>
> #define if_baudrate =C2=A0 =C2=A0 if_data.ifi_baudrate
>
> and
>
> u_long =C2=A0ifi_baudrate; =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 /* linespee=
d */
>
> so, i'm taking this as if_baudrate really should be an interface line
> speed in megabits per second. am i correct? if so, then it appears
> that at least some drivers lie about true line speed. for example from
> ixgbe(4)
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0ifp->if_baudrate =3D 1000000000;
>
> it looks like its order of magnitude lower (i.e. 1 gigabit per second
> instead of 10 gigabits per second). am i missing something here or its
> just a typo?

ixgbe's developer is excessively concerned about overflow on 32-bit
hosts (and unwilling to correct it under a preprocessor conditional),
unlike several of the other 10GbE driver developers, although I think
one 10GbE driver opts to omit if_baudrate entirely.

Thanks,
Juli.



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