[Bro] Bro cluster's CPU usage

Seth Hall seth at corelight.com
Mon Nov 6 05:21:25 PST 2017

On 5 Nov 2017, at 17:37, Shuai Hao wrote:

> Bro is running with the cluster mode, and the pf_ring is enabled to
> utilized the dual cores. We use iperf to send traffic with controlled
> target bandwidth to investigate the cpu usages of bro's processes.

That's not a good way to test Bro performance unless iperf traffic is 
what will be monitored when you move to operational use.  Since Bro is 
so heavily centered around packet parsing and logging you are just 
overwhelming certain areas of Bro and not even executing other areas of 

> The question is that sometimes we see a significant increase (60%~70%) 
> from
> cpu usages from two loggers' processes ($~bro/bin/bro -U .status -p 
> broctl
> ... logger ...). How we should understand the resources consumed by 
> the
> loggers? For our case, what is the reasonable approach to evaluate 
> Bro's
> cpu usage?

Those two logger processes you are seeing are actually a parent and 
child.  The child does the socket communication with the other Bro 
processes and the parent is the Bro process.  You will see increased cpu 
utilization from the logger as more logs are written.  The next question 
that is brought up is what logs are being written.  It's not always easy 
to guess.


Seth Hall * Corelight, Inc * www.corelight.com

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