igb and ALTQ in 9.1-rc3

[Barney Cordoba]

it needs a lot more than a patch. It needs to be completely re-thunk

--- On Fri, 3/29/13, Adrian Chadd <adrian at freebsd.org> wrote:

From: Adrian Chadd <adrian at freebsd.org>
Subject: Re: igb and ALTQ in 9.1-rc3
To: "Barney Cordoba" <barney_cordoba at yahoo.com>
Cc: "Jack Vogel" <jfvogel at gmail.com>, "Nick Rogers" <ncrogers at gmail.com>, "Jeffrey EPieper" <jeffrey.e.pieper at intel.com>, "freebsd-net at freebsd.org" <freebsd-net at freebsd.org>, "Clement Hermann (nodens)" <nodens2099 at gmail.com>
Date: Friday, March 29, 2013, 12:07 PM

Barney,
Patches gratefully accepted.



Adrian



On 29 March 2013 08:54, Barney Cordoba <barney_cordoba at yahoo.com> wrote:





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



> From: Pieper, Jeffrey E <jeffrey.e.pieper at intel.com>

> Subject: RE: igb and ALTQ in 9.1-rc3

> To: "Barney Cordoba" <barney_cordoba at yahoo.com>, "Jack Vogel" <jfvogel at gmail.com>, "Nick Rogers" <ncrogers at gmail.com>


> Cc: "freebsd-net at freebsd.org" <freebsd-net at freebsd.org>, "Clement Hermann (nodens)" <nodens2099 at gmail.com>


> Date: Friday, March 29, 2013, 11:45 AM

>

>

> -----Original Message-----

> From: owner-freebsd-net at freebsd.org

> [mailto:owner-freebsd-net at freebsd.org]

> On Behalf Of Barney Cordoba

> Sent: Friday, March 29, 2013 5:51 AM

> To: Jack Vogel; Nick Rogers

> Cc: freebsd-net at freebsd.org;

> Clement Hermann (nodens)

> Subject: Re: igb and ALTQ in 9.1-rc3

>

>

>

> --- On Thu, 3/28/13, Nick Rogers <ncrogers at gmail.com>

> wrote:

>

> > From: Nick Rogers <ncrogers at gmail.com>

> > Subject: Re: igb and ALTQ in 9.1-rc3

> > To: "Jack Vogel" <jfvogel at gmail.com>

> > Cc: "Barney Cordoba" <barney_cordoba at yahoo.com>,

> "Clement Hermann (nodens)" <nodens2099 at gmail.com>,

> "freebsd-net at freebsd.org"

> <freebsd-net at freebsd.org>

> > Date: Thursday, March 28, 2013, 9:29 PM

> > On Thu, Mar 28, 2013 at 4:16 PM, Jack

> > Vogel <jfvogel at 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 at gmail.com>

> > wrote:

> > >>

> > >> On Tue, Dec 11, 2012 at 1:09 AM, Jack Vogel

> <jfvogel at gmail.com>

> > wrote:

> > >> > On Mon, Dec 10, 2012 at 11:58 PM, Gleb

> > Smirnoff <glebius at 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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