Date: Mon, 21 Jan 2008 16:07:54 +0100 From: Sascha Holzleiter <sascha@holzleiter.name> To: freebsd-net@freebsd.org Subject: Network buffer problem Message-ID: <1200928074.66357.12.camel@dreamland.gameforge.local>
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Hi,
i've bit of an understanding issue with the netstat output which seems
to condradict itself a bit.
One of our production machines has a moderate network load (24mbit on a
100mbit device) and quite frequently shows a packet loss rate around 2%
on peak times.
A netstat -s -p ip output looks like this:
1459405058 packets sent from this host
0 packets sent with fabricated ip header
411987593 output packets dropped due to no bufs, etc.
So there are a lot of packets dropped due to buffers.
But the mbuffer statistic with netstat -m shows no sign of this:
3470/2095/5565 mbufs in use (current/cache/total)
1536/1078/2614/25600 mbuf clusters in use (current/cache/total/max)
1536/145 mbuf+clusters out of packet secondary zone in use
(current/cache)
0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
3939K/2679K/6619K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/7/6656 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
5646 calls to protocol drain routines
There are no mbufs denied ever, the mbuf max is far above the total
amount used so i'm a bit at a loss what's the problem here but it seems
to be some kind of buffer issue.
I already raised kern.ipc.maxsockbuf to 16777216 and the nmbclusters is
still at 25600 which seems fine according to the mbuf statistic above.
This is on a GENERIC FreeBSD 6.2 system with an em network card at
100mbit.
Greetings,
Sascha
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