TSO, SMP and the em driver.

[Gleb Smirnoff]

On Wed, Sep 13, 2006 at 10:46:22AM -0500, Brooks Davis wrote:
B> On Wed, Sep 13, 2006 at 11:08:44AM -0400, John Baldwin wrote:
B> > On Tuesday 12 September 2006 19:14, Andre Oppermann wrote:
B> > > Mike Tancsa wrote:
B> > > > At 12:43 PM 9/12/2006, Andre Oppermann wrote:
B> > > > 
B> > > >> TSO != (vlan && promisc)
B> > > > 
B> > > > Sorry, the commonality I was referring to was VLAN hardware tagging and 
B> > > > how it must be enabled for TSO, but that breaks other things.  See a few 
B> > > > messages ago
B> > > > 
B> > http://lists.freebsd.org/pipermail/freebsd-current/2006-September/065818.html 
B> > > 
B> > > I'm sure we can find a workaround for that.
B> > 
B> > Well, you could have the em(4) driver manually handle TSO in software, which 
B> > is what it does to workaround the VLAN tag problem.  (It does VLAN 
B> > encapsulation in the driver.)  While VLAN insertion may be trivial, 
B> > re-implementing TCP segmentation in the driver might be a good bit less 
B> > trivial to do.  There's not going to be a simple easy workaround for this 
B> > hardware bug. :(
B> 
B> I'm not sure it's worth worrying about with GbE hardware.  Just disable
B> TSO in promiscuous mode.  Where TSO is going to really matter is 10GbE.
B> No supporting TSO in some configurations with GbE doesn't seem like a
B> big deal to me.

Yes, makeing TSO and promisc mutually exclusive would be fine.

-- 
Totus tuus, Glebius.
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