Date: Tue, 27 Dec 2005 10:41:56 -0600 From: Skylar Thompson <skylar@cs.earlham.edu> To: Brian Candler <B.Candler@pobox.com> Cc: freebsd-net@freebsd.org Subject: Re: DHCP oddity Message-ID: <43B16ED4.9060803@cs.earlham.edu> In-Reply-To: <20051227130614.GA3148@uk.tiscali.com> References: <43B03332.2010904@cs.earlham.edu> <20051227130614.GA3148@uk.tiscali.com>
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Brian Candler wrote:
>On Mon, Dec 26, 2005 at 12:15:14PM -0600, Skylar Thompson wrote:
>
>
>>While doing some network stress-tests from a dual-CPU x86 FreeBSD 5.4
>>server, I noticed that a "ping -f" drives dhcpd's CPU usage way up. I
>>put dhcpd into debug mode and didn't get any error messages. I then ran
>>dhcpd with strace, and saw loads of these messages when I started the
>>ping flood:
>>
>>select(8, [?], [?], [?], NULL) = 1 ()
>>gettimeofday({...}, NULL) = 0
>>recvfrom(4, 0xbfbfe090, 1500, 0, {...}, [?]) = 84
>>select(8, [?], [?], [?], NULL) = 1 ()
>>gettimeofday({...}, NULL) = 0
>>recvfrom(4, 0xbfbfe090, 1500, 0, {...}, [?]) = 84
>>
>>Does anyone know why this would happen?
>>
>>
>
>Were you running tcpdump or similar at the same time, such that the
>interface was put into promiscuous mode?
>
>Check using ifconfig that it is not (i.e. there is no PROMISC flag shown)
>_______________________________________________
>
>
No. Here's the setup of the NIC:
bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=1a<TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
inet 159.28.234.1 netmask 0xffffff00 broadcast 159.28.234.255
inet6 fe80::210:18ff:fe11:ea1f%bge0 prefixlen 64 scopeid 0x1
ether 00:10:18:11:ea:1f
media: Ethernet autoselect (1000baseTX <full-duplex>)
status: active
I've also tried this using the on-board 100Mbps fxp adapter, and I get
the same results.
--
-- Skylar Thompson (skylar@cs.earlham.edu)
-- http://www.cs.earlham.edu/~skylar/
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