On 10/24/2011 06:24, unruh wrote:
On 2011-10-23, Uwe Klein<u...@klein-habertwedt.de> wrote:
A C wrote:
More interesting is that the cpu was pegged until I was able to kill and
restart ntpd. Most of the cpu was devoted to ntpd during this locked up
period. Simple things like typing at the console were difficult. It
would take a few seconds for a keypress to register on the screen. Once
ntpd was restarted the system responded normally and the cpu usage
dropped to normal levels.
This is still version 4.2.6p3. I should probably go ahead and compile
the most recently released version but I'm at a loss to understand why
it happened.
CPU (over)loaded
or the system is swapping like mad ?
That would destroy everything ( ie slow everything to a crawl). Also
ntpd is a small program and especially at heightened niceness (which he
said he used) should not get swapped out or affected.
( I'd think it is swapping? )
Right, the swapping would only occur if I was trying to actively do
something while diagnosing the problem. Otherwise the system load is so
low there's no real need to swap. There is no desktop environment
running on the system, only the standard daemons plus some extras (sshd,
ntpd, gpsd, crond, syslogd, inetd, postfix for system messages only) and
then one xterm (with ssh session inside) and one xclock. The cron jobs
are mostly system housekeeping (log rotation, etc.) that occur at 0:00
but the crashes would occur at other times so none of the cron jobs were
running at the time of any crash.
I've got extra RAM sticks that I pulled out during debugging in case I
had a bad memory cell but that turns out not to be the case so I'll need
to add all the sticks back in. Still the load isn't quite large enough
to swap everything out. Right now the machine is quiet and not swapping
anything unless I run something resource intensive.
The header from top when things work normally (ntpd no longer running at
high priority in this capture):
load averages: 0.10, 0.09, 0.02; up 14+20:55:09 14:44:43
22 processes: 21 sleeping, 1 on CPU
CPU states: 10.5% user, 0.0% nice, 7.4% system, 6.4% interrupt, 75.8% idle
Memory: 5048K Act, 2432K Inact, 300K Wired, 2316K Exec, 1336K File, 200K Free
Swap: 128M Total, 9272K Used, 119M Free
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND
5738 root 85 0 5416K 1004K pause 19:25 0.24% 0.24% ntpd
0 root 125 0 0K 5608K cachegc 140:35 0.05% 0.05% [system]
410 agcarver 85 0 7328K 1212K select 27:54 0.05% 0.05% xterm
323 nobody 90 -10 13M 784K select 37.7H 0.00% 0.00% gpsd
533 agcarver 85 0 11M 728K select 106:58 0.00% 0.00% sshd
415 agcarver 85 0 7172K 676K select 94:31 0.00% 0.00% xclock
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