Hi,
back from vacation I had some time to test libpcap again
> > thanks for the advice. If I use libpcap 1.1.1 compiled with the
> > HAVE_PACKET_RING stuff commented out, the my softare performs very well.
> > Ubuntu currently ships with 1.0.0.6 I think. If I use that version my
> > application has problems capturing 100 Mbit/s of traffic. If I change to
> > the custom build version of libpcap then I can capture 1 Gbit/s of traffic
> > and problem occur only for small packet sizes (<100 Byte).
>
> What happens if you build 1.1.1 with no changes (i.e., with the
> HAVE_PACKET_RING stuff *not* commented out) and use that version? That's the
> cleanest test of mmap vs. non-mmap.
If I recompile with the HAVE_PACKET_RING stuff *not* commented out I get the
bad performance as with the packaged versions from Ubuntu. So the performance
drop is caused by that part of libpcap.
> > Any idea why mmap is slowing everything down? I am using pcap_dispatch to
> > capture packet by packet.
>
> (That means you're not using pcap_next() or pcap_next_ex(), correct?)
correct
> What are you passing as the second argument to pcap_dispatch()?
1
> And how are you measuring the packet loss? Are you using the figures from
> pcap_stats(), or are you determining in some other fashion that packets
> weren't captured?-
I am generating my own packets and compare sent vs. received numbers. For
generating the packets another PC is used.
Bernd
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