Date: Wed, 13 Oct 2004 09:42:27 +0300 From: Ruslan Ermilov <ru@freebsd.org> To: Sam Leffler <sam@errno.com> Cc: freebsd-current@freebsd.org Subject: Re: Broadcom bge and 802.1Q vlan tags Message-ID: <20041013064227.GA1338@ip.net.ua> In-Reply-To: <416C3C77.20406@errno.com> References: <9256D57F598E6C41B288AA7DB94F29C902DFB963@pgnmail1.pgnaplikace.cz> <20041012140205.GD29433@cell.sick.ru> <416BFE30.2090308@errno.com> <20041012185129.GA86935@ip.net.ua> <416C3C77.20406@errno.com>
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--Q68bSM7Ycu6FN28Q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Sam, On Tue, Oct 12, 2004 at 01:20:07PM -0700, Sam Leffler wrote: > >>This pessimizes normal traffic. > > > >m_tag_locate() doesn't look like a very expensive function. And > >with the "normal traffic", I don't expect to be more than one tag, > >no? Also, if if_nvlans > 0, this is already "pessimized". > > > > > >>We should look for a solution in the=20 > >>driver(s) to avoid sending packets up with tags when no vlans are=20 > >>configured. > >> > > > >I'd be opposed to such a change in behavior. The VLAN consumer can > >be not only vlan(4), it can equally be the ng_vlan(4) node, etc. >=20 > I'm not sure what you are opposed to or why. The issue I have is that=20 > m_tag_locate can be expensive if many packets have tags. The check for= =20 > the existence of vlans configured on the interface short-circuits this=20 > work. That vlan-tagged packets may be generated when no vlans are=20 > configured seems wrong to me and breaks the assumption used to write the= =20 > code. Changing the driver to drop the frame if ifp->if_nvlans is zero=20 > seems straightforward and could probably be hidden in the existing macro. >=20 Please take a moment and re-read what I've already said: vlan(4) is not the only consumer of VLAN frames: ng_vlan(4) is another such one, and I have a proprietary Netgraph node here that demultiplexes VLANs. If you start dropping VLAN frames in drivers when if_nvlans =3D=3D 0, this will be a problem for me. Is that clear now? Cheers, --=20 Ruslan Ermilov ru@FreeBSD.org FreeBSD committer --Q68bSM7Ycu6FN28Q Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBbM5TqRfpzJluFF4RAs/rAJ0TaG8jQ8lVGUqvwLiUpI0m3yY2zQCfVKKj YiNhXCaIeIcD7zxw6yACH14= =QS3p -----END PGP SIGNATURE----- --Q68bSM7Ycu6FN28Q--
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