Re: top displaying 50% si time and 50% idle on idle machine
From: Metathronius Galabant
Date: Fri Sep 08 2006 - 17:00:32 EST
Kernel 2.6.17.11 with tg3 network driver, NAPI enabled (Distro CentOS 4.4).
top shows strangely 50% idle even if the machine is _completely_ idle.
top - 01:04:30 up 4 days, 12:05, 2 users, load average: 0.00, 0.00, 0.00
Tasks: 34 total, 2 running, 32 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0% us, 0.0% sy, 0.0% ni, 50.0% id, 0.0% wa, 0.0% hi, 50.0%si
Do `ps aux', look for a process stuck in D state.
The issue that startled me: there is _NO_ process in a D state!
BTW what means si? (interrupt service time? google didn't find anything)
ps auxwm output following:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 1692 572 ? - Sep04 0:00 init [3]
root - 0.0 - - - - Ss Sep04 0:00 -
root 2 0.0 0.0 0 0 ? - Sep04 0:00 [ksoftirqd/0]
root - 0.0 - - - - SN Sep04 0:00 -
root 3 0.0 0.0 0 0 ? - Sep04 0:00 [events/0]
root - 0.0 - - - - S< Sep04 0:00 -
root 4 0.0 0.0 0 0 ? - Sep04 0:00 [khelper]
root - 0.0 - - - - S< Sep04 0:00 -
root 5 0.0 0.0 0 0 ? - Sep04 0:00 [kthread]
root - 0.0 - - - - S< Sep04 0:00 -
root 7 0.0 0.0 0 0 ? - Sep04 0:00 [kblockd/0]
root - 0.0 - - - - S< Sep04 0:00 -
root 8 0.0 0.0 0 0 ? - Sep04 0:00 [kseriod]
root - 0.0 - - - - S< Sep04 0:00 -
root 70 0.0 0.0 0 0 ? - Sep04 0:00 [pdflush]
root - 0.0 - - - - S Sep04 0:00 -
root 71 0.0 0.0 0 0 ? - Sep04 0:00 [pdflush]
root - 0.0 - - - - S Sep04 0:00 -
root 72 0.0 0.0 0 0 ? - Sep04 0:00 [kswapd0]
root - 0.0 - - - - S Sep04 0:00 -
root 73 0.0 0.0 0 0 ? - Sep04 0:00 [aio/0]
root - 0.0 - - - - S< Sep04 0:00 -
root 672 0.0 0.0 0 0 ? - Sep04 0:00 [kpsmoused]
root - 0.0 - - - - S< Sep04 0:00 -
root 685 0.0 0.0 0 0 ? - Sep04 0:00 [kjournald]
root - 0.0 - - - - S< Sep04 0:00 -
root 1666 0.0 0.0 1588 464 ? - Sep04 0:00 udevd
root - 0.0 - - - - S<s Sep04 0:00 -
root 2065 0.0 0.0 0 0 ? - Sep04 0:00 [kjournald]
root - 0.0 - - - - S< Sep04 0:00 -
root 2073 0.0 0.0 0 0 ? - Sep04 0:00 [kjournald]
root - 0.0 - - - - S< Sep04 0:00 -
root 2763 0.0 0.0 2484 928 ? - Sep04 0:00 crond
root - 0.0 - - - - Ss Sep04 0:00 -
root 2779 0.0 0.0 1532 408 tty2 - Sep04 0:00
/sbin/mingetty tty2
root - 0.0 - - - - Ss+ Sep04 0:00 -
root 2780 0.0 0.0 1536 416 tty3 - Sep04 0:00
/sbin/mingetty tty3
root - 0.0 - - - - Ss+ Sep04 0:00 -
root 4495 0.0 0.0 2904 1236 ? - Sep04 0:00 login -- root
root - 0.0 - - - - Ss Sep04 0:00 -
root 6582 0.0 0.0 0 0 ? - Sep04 0:00 [reiserfs/0]
root - 0.0 - - - - S< Sep04 0:00 -
root 7406 0.0 0.0 2344 1380 tty1 - Sep06 0:00 -bash
root - 0.0 - - - - Ss+ Sep06 0:00 -
root 8158 0.0 0.0 4076 1132 ? - Sep06 0:01 /usr/sbin/sshd
root - 0.0 - - - - Ss Sep06 0:01 -
root 10342 0.0 0.0 2244 608 ? - Sep08 0:03 syslogd -m 0
root - 0.0 - - - - Ss Sep08 0:03 -
root 10347 0.0 0.0 1672 384 ? - Sep08 0:00 klogd -x
root - 0.0 - - - - Ss Sep08 0:00 -
root 16078 0.0 0.0 8040 2240 ? - Sep10 0:00 sshd: root@pts/0
root - 0.0 - - - - Ss Sep10 0:00 -
root 16089 0.0 0.0 2516 1256 pts/0 - Sep10 0:00 -bash
root - 0.0 - - - - Ss Sep10 0:00 -
nscd 24962 0.0 0.0 106476 840 ? - 03:43 0:00 /usr/sbin/nscd
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
nscd - 0.0 - - - - Ssl 03:43 0:00 -
root 24972 0.0 0.0 2548 724 pts/0 - 03:44 0:00 ps auxwm
root - 0.0 - - - - R+ 03:44 0:00 -
echo t > /proc/sysrq-trigger
dmesg -s 1000000 > foo
then edit foo, search for the process in D state (look for " D ") and send
that process's backtrace record.
This does only make sense if I have found the offender? I tried it,
nothing unusual and almost no output.
Is there any way to track it down? Just hints in the right direction
are highly appreciated!
Thanks,
M.
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