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Date:      Thu, 12 Feb 2004 22:42:57 +0100
From:      Emre Bastuz <info@emre.de>
To:        freebsd-net@FreeBSD.org
Subject:   4.9-STABLE heavily dropping packets? libpcap issue?
Message-ID:  <1076622177.584b09df25514@webmail.emre.de>

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Hi,

for sniffing purposes I have a FreeBSD 4.9-STABLE box running on highend,
state-of-the-art hardware (Xeon something) with all bells and whistles.

The NIC=B4s an onboard copper em0 with gig-e capabilities.

Nevertheless I am getting massive packet drops (40%-60%) when I start sniffi=
ng a
gigabit ehthernet segment although the CPU load is very low.

After doing some research in in the appropriate mailing list archives I foun=
d
out that there are (or were?) sometimes issues with the libpcap. As there wa=
s a
more current one in the ports collection (0.8.1 as opposed to 0.7 in the bas=
e
system) I used this instead (with LIBPCAP_OVERWRITE_BASE=3Dyes) but still I =
am
losing the same amount of packets when doing a tcpdump.

I definitly do _not_ know what else I can do to reduce the amount of lost da=
ta.
*sigh*

Things I did to improve the situation so far:

- Update from RELEASE to 4.9-STABLE
- Compile a custom kernel with reduced drivers and SMP support
- Update libpcap and recompile tcpdump

Does any of you have an idea else I can do?

Any parameters in the kernel that can be tweeked further, like NMBCLUSTERS o=
r
NMBUFS?

Cheers,

Emre

--
http://www.emre.de                        UIN: 561260
PGP Key ID: 0xAFAC77FD

I don't see why some people even HAVE cars. -- Calvin

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