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Date:      Fri, 29 Mar 2013 08:54:08 -0700 (PDT)
From:      Barney Cordoba <barney_cordoba@yahoo.com>
To:        Jack Vogel <jfvogel@gmail.com>, Nick Rogers <ncrogers@gmail.com>, Jeffrey EPieper <jeffrey.e.pieper@intel.com>
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, "Clement Hermann \(nodens\)" <nodens2099@gmail.com>
Subject:   RE: igb and ALTQ in 9.1-rc3
Message-ID:  <1364572448.52354.YahooMailClassic@web121605.mail.ne1.yahoo.com>
In-Reply-To: <2A35EA60C3C77D438915767F458D65687D46B19E@ORSMSX101.amr.corp.intel.com>

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--- On Fri, 3/29/13, Pieper, Jeffrey E <jeffrey.e.pieper@intel.com> wrote:

> From: Pieper, Jeffrey E <jeffrey.e.pieper@intel.com>
> Subject: RE: igb and ALTQ in 9.1-rc3
> To: "Barney Cordoba" <barney_cordoba@yahoo.com>, "Jack Vogel" <jfvogel@gmail.com>, "Nick Rogers" <ncrogers@gmail.com>
> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, "Clement Hermann (nodens)" <nodens2099@gmail.com>
> Date: Friday, March 29, 2013, 11:45 AM
> 
> 
> -----Original Message-----
> From: owner-freebsd-net@freebsd.org
> [mailto:owner-freebsd-net@freebsd.org]
> On Behalf Of Barney Cordoba
> Sent: Friday, March 29, 2013 5:51 AM
> To: Jack Vogel; Nick Rogers
> Cc: freebsd-net@freebsd.org;
> Clement Hermann (nodens)
> Subject: Re: igb and ALTQ in 9.1-rc3
> 
> 
> 
> --- On Thu, 3/28/13, Nick Rogers <ncrogers@gmail.com>
> wrote:
> 
> > From: Nick Rogers <ncrogers@gmail.com>
> > Subject: Re: igb and ALTQ in 9.1-rc3
> > To: "Jack Vogel" <jfvogel@gmail.com>
> > Cc: "Barney Cordoba" <barney_cordoba@yahoo.com>,
> "Clement Hermann (nodens)" <nodens2099@gmail.com>,
> "freebsd-net@freebsd.org"
> <freebsd-net@freebsd.org>
> > Date: Thursday, March 28, 2013, 9:29 PM
> > On Thu, Mar 28, 2013 at 4:16 PM, Jack
> > Vogel <jfvogel@gmail.com>
> > wrote:
> > > Have been kept fairly busy with other matters,
> one
> > thing I could do short
> > > term is
> > > change the defines in igb the way I did in the em
> > driver so you could still
> > > define
> > > the older if_start entry. Right now those are
> based on
> > OS version and so you
> > > will
> > > automatically get if_transmit, but I could change
> it to
> > be IGB_LEGACY_TX or
> > > so,
> > > and that could be defined in the Makefile.
> > >
> > > Would this help?
> > 
> > I'm currently using ALTQ successfully with the em
> driver, so
> > if igb
> > behaved the same with respect to using if_start instead
> of
> > if_transmit
> > when ALTQ is in play, that would be great. I do not
> > completely
> > understand the change you propose as I am not very
> familiar
> > with the
> > driver internals. Any kind of patch or extra
> > Makefile/make.conf
> > definition that would allow me to build a 9-STABLE
> kernel
> > with an igb
> > driver that works again with ALTQ, ASAP, would be much
> > appreciated.
> > 
> > >
> > > Jack
> > >
> > >
> > >
> > > On Thu, Mar 28, 2013 at 2:31 PM, Nick Rogers
> <ncrogers@gmail.com>
> > wrote:
> > >>
> > >> On Tue, Dec 11, 2012 at 1:09 AM, Jack Vogel
> <jfvogel@gmail.com>
> > wrote:
> > >> > On Mon, Dec 10, 2012 at 11:58 PM, Gleb
> > Smirnoff <glebius@freebsd.org>
> > >> > wrote:
> > >> >
> > >> >> On Mon, Dec 10, 2012 at 03:31:19PM
> -0800,
> > Jack Vogel wrote:
> > >> >> J> UH, maybe asking the owner of
> the
> > driver would help :)
> > >> >> J>
> > >> >> J> ... and no, I've never been
> aware of
> > doing anything to stop
> > >> >> supporting
> > >> >> altq
> > >> >> J> so you wouldn't see any
> commits. If
> > there's something in the altq
> > >> >> code
> > >> >> or
> > >> >> J> support (which I have nothing
> to do
> > with) that caused this no-one
> > >> >> informed
> > >> >> J> me.
> > >> >>
> > >> >> Switching from if_start to
> if_transmit
> > effectively disables ALTQ
> > >> >> support.
> > >> >>
> > >> >> AFAIR, there is some magic
> implemented in
> > other drivers that makes them
> > >> >> modern (that means using
> if_transmit), but
> > still capable to switch to
> > >> >> queueing
> > >> >> mode if SIOCADDALTQ was casted upon
> them.
> > >> >>
> > >> >>
> > >> > Oh, hmmm, I'll look into the matter after
> my
> > vacation.
> > >> >
> > >> > Jack
> > >>
> > >> Has there been any progress on resolving this
> > issue? I recently ran
> > >> into this problem upgrading my servers from
> 8.3 to
> > 9.1-RELEASE and am
> > >> wondering what the latest recommendation is.
> I've
> > used ALTQ and igb
> > >> successfully for years and it is unfortunate
> it no
> > longer works.
> > >> Appreciate any advice.
> > >>
> >
> >Do yourself a favor and either get a cheap dual port
> 82571 card or
> >2 cards and disable the IGB ports. The igb driver is
> defective, and until
> >they back out the new, untested multi-queue stuff you're
> just neutering 
> >your system trying to use it.
> >
> >Frankly this project made a huge mistake by moving
> forward with multi
> >queue just for the sake of saying that you support it;
> without having
> >any credible plan for implementing it. That nonsense
> that Bill Macy did
> >should have been tarballed up and deposited in the trash
> folder. The
> >biggest mess in programming history.
> >
> >That being said, the solution is not to hack the igb
> driver; its to make
> >ALTQ if_transmit compatible, which shouldn't be all that
> difficult. 
> >
> >BC
> 
> I may be misunderstanding what you are saying, but if the
> solution is, as you say "not to hack the igb driver", then
> how is it defective in this case? Or are you just directing
> vitriol toward Intel? Multi-queue is working fine in igb. 
> 
> Jeff

It's defective because it's been poorly implemented and has more bugs 
than a Manhattan hotel bed. Adding queues without a proper plan just add
more lock contention. It's not a production-ready driver.

As Jack once said, Intel doesn't care about performance, they're just
example drivers. igb is an example of how not to do things.

BC



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