Argus 3.0.6 and dnaclusters

Chris Wakelin c.d.wakelin at
Thu Dec 13 17:37:31 EST 2012

Yes it's a bug in DNA. I can't remember seeing a commit that claimed to
fix it; the last I saw, I think on the topic was the developer's reply to

(and IPv6 is fine now BTW :-) )

As far as I remember, for some reason Bro IDS manages to use select()
without hitting the problem, I think, perhaps by adding empty select()
calls with a timeout:

>From Bro's

>         if ( all_idle )
>                 {
>                 // Interesting: when all sources are dry, simply sleeping a
>                 // bit *without* watching for any fd becoming ready may
>                 // decrease CPU load. I guess that's because it allows
>                 // the kernel's packet buffers to fill. - Robin
>                 timeout.tv_sec = 0;
>                 timeout.tv_usec = 20; // SELECT_TIMEOUT;
>                 select(0, 0, 0, 0, &timeout);
>                 }

I had a go at doing that in ARGUS but it made no difference (perhaps I
put it in the wrong place!).

I'm happy to try things out on the test server, now I've updated
everything (I'm using tcpreplay of a 10GB pcap over a 1Gb link from
another machine using Intel e1000e cards and the time-limited DNA demo
licence, so I can only test for 5 mins at a time).

Best Wishes,

On 13/12/12 22:11, Carter Bullard wrote:
> If I remember, the 100% CPU was a bug in the DNA code itself?
> Was there a resolution to that?
> If you would be a guinea pig, we can play around with it?
> Carter 
> On Dec 13, 2012, at 4:30 PM, Chris Wakelin <c.d.wakelin at> wrote:
>> I've just tried with latest PF_RING svn (post v5.5.1) and DNA
>> clusters on a test machine. It looks like we do still need the name
>> change (added "dna" to the list of interfaces that includes "dag" and
>> "napa") and it still uses 100% of CPU, but otherwise appears to work.
>> Best Wishes,
>> Chris

Christopher Wakelin,                           c.d.wakelin at
IT Services Centre, The University of Reading,  Tel: +44 (0)118 378 8439
Whiteknights, Reading, RG6 2AF, UK              Fax: +44 (0)118 975 3094

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