[Voyage-linux] Cron 100% CPU
bentscrewdriver
(spam-protected)
Sat Aug 11 02:20:35 HKT 2012
Oddly enough this turned out to be an issue with the date. While
testing I hadn't yet set the date on any of them (was something like
Tue Feb 15 21:33:36 EWT 1944). Cron must run calculations on the date,
even if it has no work, or is not doing anything, and this was causing
it to go haywire on every wakeup. Still not sure why I didn't see the
symptom until I installed keepalived but perhaps I didn't wait long
enough for it to start (first hourly run, etc). At any rate, setting
the system instantly stopped cron from spiking to 100% on all 3
net6501's. I can sleep now....
On Fri, Aug 10, 2012 at 2:48 AM, Teco Boot <teco at inf-net.nl> wrote:
> Is /var/spool/cron cleaned up?
> Can you run with debug on?
>
> Teco
>
> Op 7 aug. 2012, om 15:24 heeft bentscrewdriver het volgende geschreven:
>
>> Okay, this one still has me puzzled. I've downgraded the net6501 to
>> 0.7.5 with the same results. I can consistently duplicate this issue
>> by performing a fresh install, installing only keepalived and haproxy,
>> rebooting and cron start spiking to 100%, at what looks like, each
>> wakeup. The odd thing is that if I remove those two packages and
>> reboot cron still spikes. I then clear out /etc/crontab and
>> /etc/cron.daily, restart cron - and it still spikes. The only thing
>> I've found to stop it is another fresh install or /etc/init.d/cron
>> stop (of course).
>>
>> Any ideas on this? Punky - can you duplicate it on your 6501?
>>
>> On Fri, Jul 27, 2012 at 11:06 AM, bentscrewdriver
>> <bentscrewdriver at gmail.com> wrote:
>>> I commented everything out in /etc/crontab and there are no other
>>> crontabs for any users (/var/spool/cron/crontabs) so it shouldn't even
>>> be running anything. This is why i am puzzled by the high usage.
>>>
>>> On Fri, Jul 27, 2012 at 10:54 AM, Teco Boot <teco at inf-net.nl> wrote:
>>>> What is in /etc/crontab?
>>>> What happens if you run the cron commands by hand?
>>>>
>>>> Teco
>>>>
>>>> Op 27 jul. 2012, om 16:26 heeft bentscrewdriver het volgende geschreven:
>>>>
>>>>> I've stopped keepalived as well as haproxy and cron still spikes to
>>>>> 100% and stays there for a minute or so. Any other ideas? lsof
>>>>> doesn't show anything different...thanks.
>>>>>
>>>>> top - 21:47:06 up 10 days, 22:47, 3 users, load average: 0.30, 0.44, 0.48
>>>>> Tasks: 44 total, 2 running, 41 sleeping, 0 stopped, 1 zombie
>>>>> Cpu(s): 67.2%us, 32.5%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
>>>>> Mem: 2075148k total, 130808k used, 1944340k free, 256k buffers
>>>>> Swap: 0k total, 0k used, 0k free, 103936k cached
>>>>>
>>>>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
>>>>> 22561 root 20 0 2120 492 372 R 100 0.0 7:51.65 cron
>>>>> 29911 root 20 0 2372 1032 820 R 1 0.0 8:42.16 top
>>>>> 4 root 20 0 0 0 0 S 0 0.0 4:04.04 kworker/0:0
>>>>> 1 root 20 0 2072 672 580 S 0 0.0 0:20.41 init
>>>>> 2 root 20 0 0 0 0 S 0 0.0 0:00.00 kthreadd
>>>>> 3 root 20 0 0 0 0 S 0 0.0 0:00.01 ksoftirqd/0
>>>>> 5 root 20 0 0 0 0 S 0 0.0 0:00.06 kworker/u:0
>>>>> 6 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
>>>>> 7 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
>>>>> 8 root 20 0 0 0 0 S 0 0.0 0:00.00 kworker/1:0
>>>>> 9 root 20 0 0 0 0 S 0 0.0 0:00.01 ksoftirqd/1
>>>>> 10 root 20 0 0 0 0 S 0 0.0 0:05.88 kworker/0:1
>>>>> 11 root 0 -20 0 0 0 S 0 0.0 0:00.00 khelper
>>>>> 12 root 20 0 0 0 0 S 0 0.0 0:00.49 kdevtmpfs
>>>>> 13 root 20 0 0 0 0 S 0 0.0 0:00.00 kworker/u:1
>>>>> 123 root 20 0 0 0 0 S 0 0.0 71571:58 sync_supers
>>>>> 125 root 20 0 0 0 0 S 0 0.0 0:00.09 bdi-default
>>>>>
>>>>>
>>>>> p
>>>>>
>>>>> On Thu, Jul 26, 2012 at 9:04 PM, Kim-man 'Punky' TSE
>>>>> <punkytse at punknix.com> wrote:
>>>>>> On 7/27/2012 12:34 AM, bentscrewdriver wrote:
>>>>>>>
>>>>>>> 26652 ? Ss 0:36 /usr/sbin/keepalived
>>>>>>> 26654 ? S 0:39 /usr/sbin/keepalived
>>>>>>> 26655 ? S 6:57 /usr/sbin/keepalived
>>>>>>> 29529 ? Rs 4:29 /usr/sbin/cron -L 2
>>>>>>
>>>>>> As shown, cron and keepalived spend much more user time than others. May be
>>>>>> you should check what you have done with keepalived first.
>>>>>>
>>>>>> --
>>>>>> Regards,
>>>>>> Kim-man "Punky" Tse
>>>>>>
>>>>>> * Open Source Embedded Solutions and Systems
>>>>>> - Voyage Linux (http://linux.voyage.hk)
>>>>>> - Voyage ONE (http://linux.voyage.hk/voyage-one)
>>>>>> - Voyage MPD (http://linux.voyage.hk/voyage-mpd)
>>>>>> * Voyage Store (http://store.voyage.hk)
>>>>>>
>>>>>>
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