em network issues

[Bill Paul]

[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

--
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-Bill Paul            (510) 749-2329 | Senior Engineer, Master of Unix-Fu
                 wpaul at windriver.com | Wind River Systems
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              <adamw> you're just BEGGING to face the moose
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