dhclient taking all cpu
Wilko Bulte
wb at freebie.xs4all.nl
Tue Jul 26 20:01:03 GMT 2005
On Tue, Jul 26, 2005 at 12:33:24PM -0700, Brooks Davis wrote..
> On Mon, Jul 25, 2005 at 10:39:09PM -0400, Mike Jakubik wrote:
> > On Mon, July 25, 2005 9:54 pm, Brooks Davis said:
> >
> > >>> Probably something wrong with your interface, but you havent't
> > >>> provided any useful information so who knows. At the very least, I
> > >>> need to know what interface you are running on, something about it's
> > >>> status, and if both dhclient processes are running.
> > >>>
> > >> The interface is xl0 (3Com 3c905C-TX Fast Etherlink XL), and it worked
> > >> in this machine fine for as long as i remember. This seems to have
> > >> happened since a recent cvsup and buildworld from ~6-BETA to 7-CURRENT.
> > >> I rebooted three times, and the problem occured rougly a minute after
> > >> bootup. On the fourth time however, it seems to be ok so far.
> > >
> > > That sounds like a problem with the code that handles the link state
> > > notifications in the interface driver. The notifications are a reletivly
> > > new feature that we're only now starting to use heavily so there are going
> > > to be bumps in the road. It would be intresting to know if you see link
> > > state messages promptly if you plug and unplug the network cable.
> >
> > It seems to be back at it again, this time it took longer to kick in. Here
> > is a "ps auxw|grep dhclient" :
> >
> > _dhcp 219 93.5 0.2 1484 1136 ?? Rs 8:49PM 5:06.00 dhclient:
> > xl0 (dhclient)
> > root 193 0.0 0.2 1484 1088 d0- S 8:49PM 0:00.02 dhclient:
> > xl0 [priv] (dhclient)
> >
> > top:
> >
> > PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND
> > 219 _dhcp 1 129 0 1484K 1136K RUN 9:33 94.24% dhclient
> >
> > Nothing in dmesg about link state changes on xl0. Unplugging and
> > replugging the network cable results in link state notification within a
> > couple seconds.
>
> Could you see what happens if you run dhclient in the foreground? Just
> running "dhclient -d xl0" should do it. I'd like to know what sort of
> output it's generating.
In my case it is not displaying anything:
chuck#dhclient -d ath0
DHCPREQUEST on ath0 to 255.255.255.255 port 67
DHCPACK from 192.168.5.254
bound to 192.168.5.20 -- renewal in 21600 seconds.
<nothing>
I can tell the phenomenon occurs when my laptop fan springs to life:
CPU states: 96.5% user, 0.0% nice, 2.7% system, 0.8% interrupt, 0.0%
idle
Mem: 48M Active, 28M Inact, 50M Wired, 680K Cache, 34M Buf, 115M Free
Swap: 257M Total, 257M Free
PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND
719 _dhcp 1 129 0 1384K 1092K RUN 2:14 93.55% dhclient
607 root 1 98 0 34584K 21212K select 0:09 1.81% Xorg
663 wb 4 20 0 46712K 40224K kserel 0:27 0.00% mozilla-bin
503 root 1 8 0 1184K 796K nanslp 0:07 0.00% powerd
Took (best guess) approx 5-10 minutes for the effect to kick in.
--
Wilko Bulte wilko at FreeBSD.org
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