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gAMBOOKa
Asked: 2011-02-23 00:08:12 +0800 CST

top: What does cpu usage mean?

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I have several processes right now running at 100%. Is it 100% of the alloted resources to the process?

UPDATE

Take a look at this for example:

top - 06:01:13 up 5 days, 22:19,  2 users,  load average: 0.74, 1.24, 1.12
Tasks: 297 total,   1 running, 296 sleeping,   0 stopped,   0 zombie
Cpu(s):  1.2%us,  0.1%sy,  0.0%ni, 97.9%id,  0.8%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  16427436k total,  8568996k used,  7858440k free,   397168k buffers
Swap: 10217332k total,    76996k used, 10140336k free,  7047904k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
27652 user  15   0  124m  14m 7076 S 15.9  0.1   0:10.84 php
 4554 mysql     15   0  728m 116m 3668 S  1.7  0.7   1325:23 mysqld
17453 nobody    20   0  427m  15m 2304 S  0.3  0.1   2:01.39 httpd
27836 root      15   0 12876 1240  808 R  0.3  0.0   0:00.06 top
    1 root      15   0 10352  684  572 S  0.0  0.0   0:03.01 init
    2 root      RT  -5     0    0    0 S  0.0  0.0   0:00.37 migration/0

Total CPU usage is aroung 2.1% while php is using 15% alone

UPDATE

I run mpstat at the same time and this is the output, showing 91% is idle

03:31:48 AM  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
03:31:48 AM  all    7.28    0.29    0.46    0.87    0.01    0.03    0.00   91.07   1119.57
central-processing-unit linux resources top

2 Answers

  1. Best Answer

    The service is using 100% processing capacity of one or other CPU in multiprocessor system.

    You will find more about top command in link below.

    http://www.kernelhardware.org/linux-top-command/

    • 1

  2. It's 100% of a logical CPU time, so a core or half a core in a HT-enabled system.

    • 0