Subject: Re: Getting physical packet counts with LRO enabled with ixgbe?

From: Ben Greear <[email-masked]>
Date: Wed, 23 Sep 2009 11:56:04 -0700

On 09/23/2009 11:50 AM, Peter P Waskiewicz Jr wrote:

>> That's a bummer.  I'm guessing you might get close to right on average with some
>> trivial math, but if someone is sending you pkts with size of 1000 and
>> your MTU is 1500, would there be any way to tell that the pkts were originally
>> 1000 bytes instead of 1500?
>
> Good point.
>
>> Next time you guys re-compile your hardware, please consider adding byte counters :)
>
> On 10G adapters, byte counters can skyrocket quickly, so we'd need to
> read them often to avoid them wrapping.  But I will forward your request
> to our HW design folks and see if they have other ideas to implement
> these counters and make them efficient.

It still takes a while to wrap 64-bit counters :)

But, you do have to read every 3 secs or so if you're using 32-bit counters.

This can be dealt with in user-space easily enough as long as polling
the NIC for counters is efficient.

Thanks,
Ben

-- 
Ben Greear <[email-masked]>
Candela Technologies Inc  http://www.candelatech.com