em network issues

Jack Vogel jfvogel at gmail.com
Fri Oct 20 17:41:27 UTC 2006

On 10/20/06, Scott Long <scottl at samsco.org> wrote:
> Bill Paul wrote:
> > [Charset ISO-8859-1 unsupported, filtering to ASCII...]
> >
> >>On 10/19/06, Kris Kennaway <kris at obsecurity.org> wrote:
> >>
> >>>On Thu, Oct 19, 2006 at 02:18:13PM -0700, Jack Vogel wrote:
> >>>
> >>>>The engineer in our test group has installed 6.2 BETA2 and attempted via a
> >>>>number of tests to reproduce this problem, the machine even shares the em
> >>>>interrupt with usb, and yet so far he has been unsuccessful.
> >>>
> >>>What tests is he running?
> >>
> >>He tried doing something Kip said reliably repro'd the issue, building a big
> >>source archive over NFS. Then he has been running a continuous NFS data
> >>back and forth copy since, that is still ongoing.
> >>
> >>Other suggestions?
> >>
> >>Jack
> >>
> >
> >
> > Just out of curiosity, what sort of torture tests does Intel do, in
> > general, on the em driver on FreeBSD? One thing that I've found which
> > works wonders at exposing race conditions is the Smartbits bi-directional
> > IP forwarding test. Put two NICs in a system, configure for it for IP
> > forwarding, then connect the Smartbits to each port and run the
> > SmartApps router test in bi-directional mode. At 64 bytes per frame,
> > it will try to push 2.96 million packets/second through both ports
> > simultaneously (1.48 million in each direction). Of course, you won't
> > actually be able to forward all the traffic, but the interfaces (not
> > to mention the OS) should continue running regardless.
> >
> > This test exercises both the RX and TX paths and generates hundreds of
> > thousands of interrupts per second. You'd be amazed at the sort of
> > things you can discover with it. The downside of course is that a
> > Smartbits with gigE ports isn't cheap, but I'd be surprised if Intel
> > didn't have one kicking around somewhere.
> >
> > -Bill
> >
> This is exactly the test that Andre and I were running, though only in
> one direction (I think due to lack of hardware for a full test).
> Prior to the INTR_FAST change, the machine would live-lock.  Now it
> survives, stays responsive, and drops packets as needed.

I just checked with our group lead (John Ronciak) and he says I have
a Smartbits available to me, so I'm gonna try and get this set up :)

Thanks for the suggestion Bill.


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