packet drop counters?

Bill Mccormick billmcc at
Thu Jun 5 14:47:30 EDT 2008

thx Dan,  I didn't realize the olpc driver was different from the
mainstream one.

I had examined the iwconfig and ifconfig counters (also netstat I think)
and they showed no packet loss, so I was wondering if there were driver
or device debug counters that could be collected.

I don't remember seeing the ethtool counters Javier mentioned so I'll
try those tomorrow with static routes configured to eliminate any
potential multiple hops.


-----Original Message-----
From: Dan Williams [mailto:dcbw at] 
Sent: Thursday, June 05, 2008 12:34 PM
To: Mccormick, Bill (CAR:CTO2)
Cc: libertas-dev at
Subject: Re: packet drop counters?

On Thu, 2008-06-05 at 11:17 -0400, Bill Mccormick wrote:
> Hi everyone,
> I'm doing some traffic testing with the libertas driver on the OLPC.
> I'm using olpc build 709 (which doesn't tell you the driver version, 
> I'll track that down).

The driver version is whatever the kernel version is that includes the
driver.  In this case, it'll be the OLPC kernel SHA1 hash code that
you'd get from doing a 'rpm -qv kernel'.  Since OLPC generally uses
older driver revisions than what's upstream, and has lots of
not-upstreamed patches from Marvell/CozyBit, it's kind of hard to match
up what you'll be using to what's in the upstream kernel, unfortunately.

> I'm seeing some intermittant, but fairly large bursts of packet loss 
> when I run the tests.
> For example, one scenario is I have 2 pairs of XOs.   Each pair has a
> source and a sink.
> When the sources are sending 1000 byte UDP packets at 600 packets per 
> second, I have seen up to 2000 packets dropped over a 5 second
> Most of the time it works well but once in a while I get these large 
> bursts of traffic loss.
> Are there any counters, etc. I can retrieve from the driver to help 
> debug this?

Are you looking for something more than the output of ifconfig and
iwconfig here?


> thanx
> Bill McCormick
> Open innovation lab
> Nortel
> ESN 393-6298
> External (613) 763-6298
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> libertas-dev mailing list
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