em network issues

Jack Vogel jfvogel at gmail.com
Fri Oct 20 16:50:50 UTC 2006


On 10/20/06, Bill Paul <wpaul at freebsd.org> 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.

Oh sure, they have Smartbits and a host of other hardware, but remember
that this group tests Windows, Linux, FreeBSD, and a number of special
case stuff. And guess what gets the most attention.... uhuh it isnt us :)

The good thing is I believe most of the same battery of tests that run on
Linux also get run against FreeBSD, so its significant, but something
like what you are talking about is probably only done when there's a
problem being investigated.

Also, its a different org in our division, I dont know the details of all the
tests they run, but they provide me with a steady stream of bug reports
so they ARE doing their job :)

Jack


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