0% CPU in top for all processes, but load average > 1
- by chrisdew
On two different servers (with Ubuntu 12.04LTS AMD64) I have seen the following behaviour:
op - 10:50:05 up 305 days, 21:17, 1 user, load average: 1.94, 2.52, 2.97
Tasks: 141 total, 2 running, 139 sleeping, 0 stopped, 0 zombie
Cpu(s): 41.5%us, 6.5%sy, 0.0%ni, 51.8%id, 0.0%wa, 0.2%hi, 0.1%si, 0.0%st
Mem: 8178432k total, 5753740k used, 2424692k free, 159480k buffers
Swap: 15625208k total, 0k used, 15625208k free, 4905292k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 23928 2072 1216 S 0 0.0 0:56.42 init
2 root 20 0 0 0 0 S 0 0.0 0:00.01 kthreadd
3 root RT 0 0 0 0 S 0 0.0 0:01.23 migration/0
4 root 20 0 0 0 0 S 0 0.0 2:39.82 ksoftirqd/0
5 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
6 root RT 0 0 0 0 S 0 0.0 0:02.99 migration/1
7 root 20 0 0 0 0 S 0 0.0 2:32.15 ksoftirqd/1
8 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/1
9 root RT 0 0 0 0 S 0 0.0 0:11.67 migration/2
10 root 20 0 0 0 0 S 0 0.0 29:00.34 ksoftirqd/2
The server is working fine, but top shows all processes as using 0% CPU. A reboot fixed this on an earlier machine, but I haven't yet tried it on this one.
I have tried top several times, and so am sure that I haven't accidentally pressed '<' or '' to sort by a different column. Sorting the process list by all of the available columns, stills shows 0% CPU for all displayed processes.
What is going on? If this a kernel bug?
Update: If I use top -p <PID> for a know, busy process, top still displays 0% CPU for that process.
