Where is my CPU usage going?
- by Josh
My Ubuntu 10.04 Lucid virtual machine is saying it's at 100% CPU usage... but all I'm running is Thunderbird. According to top, CPU usage should be ~25.9%... How do I interpret this conflicting output from top?
top - 13:55:26 up 3:35, 4 users, load average: 3.03, 2.59, 2.48
Tasks: 178 total, 1 running, 177 sleeping, 0 stopped, 0 zombie
Cpu(s): 16.0%us, 79.7%sy, 0.0%ni, 0.0%id, 0.0%wa, 1.3%hi, 3.0%si, 0.0%st
Mem: 509364k total, 479108k used, 30256k free, 3092k buffers
Swap: 2096440k total, 58380k used, 2038060k free, 225116k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7708 jnet 20 0 480m 109m 17m S 18.4 22.1 21:59.14 thunderbird-bin
4615 jnet 20 0 5488 1268 1040 S 2.3 0.2 5:00.03 nx-rootless-ses
7124 jnet 20 0 56688 27m 4812 S 2.0 5.5 6:35.09 nxagent
6724 nx 20 0 9628 1400 636 S 1.6 0.3 3:26.59 sshd
30106 root 20 0 2544 1236 908 R 0.7 0.2 0:00.33 top
19 root 20 0 0 0 0 S 0.3 0.0 0:22.45 ata/0
38 root 20 0 0 0 0 S 0.3 0.0 0:05.53 scsi_eh_1
345 root 20 0 0 0 0 S 0.3 0.0 0:04.72 kjournald
1719 root 20 0 3260 1192 944 S 0.3 0.2 0:17.36 vmware-guestd
1 root 20 0 2804 1356 940 S 0.0 0.3 0:01.99 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.01 kthreadd
3 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
4 root 20 0 0 0 0 S 0.0 0.0 0:00.15 ksoftirqd/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
...
Specifically I'm referring to the fact that the CPU usage totals show 0% idle time:
Cpu(s): 16.0%us, 79.7%sy, 0.0%ni, 0.0%id, 0.0%wa, 1.3%hi, 3.0%si, 0.0%st
Yet when adding up the percentages in the %CPU column I get 25.9%, not 100%!