dhclient taking all cpu
Eric Anderson
anderson at centtech.com
Wed Jul 27 19:47:31 GMT 2005
Brooks Davis wrote:
> On Wed, Jul 27, 2005 at 02:35:06PM -0500, Eric Anderson wrote:
>
>>Brooks Davis wrote:
>>
>>>On Tue, Jul 26, 2005 at 04:39:33PM -0700, Brooks Davis wrote:
>>>
>>>
>>>>On Tue, Jul 26, 2005 at 06:53:17PM -0400, Jung-uk Kim wrote:
>>>>
>>>>
>>>>>On Tuesday 26 July 2005 04:00 pm, Wilko Bulte wrote:
>>>>>
>>>>>
>>>>>>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.
>>>>>
>>>>>FYI, I have the same issues with bge(4) and ndis(4).
>>>>
>>>>I've seen it on ath and em interfaces now, but am not sure what's going
>>>>on. and have no idea how to reproduce the problem. As also reported by
>>>>Bakul Shah, we seem to be getting into a state where receive_packet() is
>>>>spinning. I'm not seeing an obvious way for this to be possible.
>>>
>>>
>>>I think I've found it. There was a really odd typo (= instead of +) in
>>>the code that handles undersized captures on the bpf socket. Please try
>>>the following patch and see if it solves the problem. I'm testing here,
>>>but I don't have a reliable way to trigger the bug. The fix is fairly
>>>obvious so I'll commit it to head shortly.
>>
>>It's been 20 minutes without any issues - I think that did it. Thanks!
>
>
> Great! Thanks for the report.
I give up. Now it's back to it's dirty ways. Ran for 22 mins without
issue (with -d option), so I reran without the -d, and it spiked within
a few minutes.
I'll now wait until someone else claims it works before commenting on it
since my computer seems to enjou making me look bad. :)
Eric
--
------------------------------------------------------------------------
Eric Anderson Sr. Systems Administrator Centaur Technology
Anything that works is better than anything that doesn't.
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