From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: multi bpf filter will impact performance?
Date: Tue, 30 Nov 2010 11:01:44 +0100
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To: Rui <wirelesser@gmail.com>
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Le mardi 30 novembre 2010 =C3=A0 17:22 +0800, Rui a =C3=A9crit :

> step 0:
> launch 4 tcpdump processes,each applied a filter to filter out some
> GTP-U packets. seen with 'tcpdump -d', the bpf code has about 100
> lines.

So each incoming packet has to go through your 4 filters, thats a total
of ~400 bpf instructions. (a bit less in average because of the
conditionnal branches)