process cpu usage

ahmedb72 · 09-06-2010, 10:32 AM

Hi all,

If I, using sar or vmstat, found that there is a CPU load on my Linux box. How can I know the top processes consuming the CPU?

Thanks in advance.

RHEL 5.2

AlucardZero · 09-06-2010, 11:04 AM

"ps" or "top" ?

ahmedb72 · 09-06-2010, 11:10 AM

top is an interactive command. I need a command line statement.

Regarding ps, what are the options to display most CPU demanding processes?

djsmiley2k · 09-06-2010, 11:27 AM

Google says...

Quote:

Originally Posted by The interwebs

k spec specify sorting order. Sorting syntax is
[+|-]key[,[+|-]key[,...]] Choose a multi-letter key from the
STANDARD FORMAT SPECIFIERS section. The "+" is optional since
default direction is increasing numerical or lexicographic
order. Identical to --sort. Examples:
ps jaxkuid,-ppid,+pid
ps axk comm o comm,args
ps kstart_time -ef

As for working out what k is, I'll leave that as an exercise for the reader

Quote:

hint: google ps man page

smoker · 09-06-2010, 12:06 PM

Quote:

Originally Posted by ahmedb72

top is an interactive command.

Not strictly true.

try running

Code:

top -n 1

AlucardZero · 09-06-2010, 12:55 PM

Are you asking for a historical list?

ahmedb72 · 09-06-2010, 01:08 PM

Hi Smoker,

"top -n 1" gives me output similar to what I want. But I'm suspicious about what it displays though. Because I'm running dozens of client processes which all consume CPU. ps command displays those processes, but the top command displays only a fraction of them.

Code:

[root@srv100] top -n 1
top - 04:04:04 up  3:05,  3 users,  load average: 87.93, 52.05, 21.98
Tasks: 304 total,  89 running, 215 sleeping,   0 stopped,   0 zombie
Cpu(s): 11.3%us,  0.6%sy,  0.0%ni, 87.5%id,  0.5%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2075608k total,  1113028k used,   962580k free,    77180k buffers
Swap:  4194296k total,   443820k used,  3750476k free,   426336k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
24855 oracle    25   0 1164m  22m  21m R   20  1.1   0:06.79 oracle
24857 oracle    25   0 1164m  22m  20m R   20  1.1   0:08.99 oracle
24897 oracle    25   0 1164m  22m  20m R   20  1.1   0:07.30 oracle
24905 oracle    25   0 1164m  22m  20m R   20  1.1   0:07.09 oracle
25028 oracle    25   0 1164m  23m  21m R   20  1.1   0:05.69 oracle
25073 oracle    25   0 1164m  22m  21m R   20  1.1   0:07.10 oracle
25077 oracle    25   0 1164m  23m  21m R   20  1.1   0:06.09 oracle
25085 oracle    25   0 1164m  23m  21m R   20  1.1   0:05.49 oracle
24774 oracle    25   0 1164m  22m  20m R   12  1.1   0:09.15 oracle
25026 oracle    25   0 1164m  22m  21m R   12  1.1   0:07.15 oracle
24901 oracle    25   0 1164m  23m  21m R   10  1.1   0:06.69 oracle
25079 oracle    25   0 1164m  23m  21m R   10  1.2   0:05.39 oracle
    1 root      15   0  2060  624  532 S    0  0.0   0:01.86 init
    2 root      RT  -5     0    0    0 S    0  0.0   0:00.34 migration/0
    3 root      34  19     0    0    0 R    0  0.0   0:00.00 ksoftirqd/0
    4 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/0
    5 root      RT  -5     0    0    0 S    0  0.0   0:00.55 migration/1
    6 root      37  19     0    0    0 R    0  0.0   0:00.00 ksoftirqd/1
    7 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/1
    8 root      10  -5     0    0    0 S    0  0.0   0:00.00 events/0
    9 root      10  -5     0    0    0 S    0  0.0   0:00.00 events/1
   10 root      10  -5     0    0    0 S    0  0.0   0:00.00 khelper
   11 root      11  -5     0    0    0 S    0  0.0   0:00.00 kthread
   15 root      10  -5     0    0    0 S    0  0.0   0:00.54 kblockd/0
   16 root      10  -5     0    0    0 S    0  0.0   0:00.10 kblockd/1
   17 root      15  -5     0    0    0 S    0  0.0   0:00.00 kacpid
  178 root      13  -5     0    0    0 S    0  0.0   0:00.00 cqueue/0
  179 root      13  -5     0    0    0 S    0  0.0   0:00.00 cqueue/1
  182 root      13  -5     0    0    0 S    0  0.0   0:00.00 khubd
  184 root      10  -5     0    0    0 S    0  0.0   0:00.00 kseriod

# see here number of commands
[root@srv100] ps -ef | grep oracle | wc -l
202

syg00 · 09-06-2010, 06:05 PM

You were advised to read the manpage(s) - had you done so, you would know:
- "ps" can be (even reverse) sorted on any column
- "top" can show threads individually, or accumulated.

Personally I find "ps" more useful for this kind of thing, as it can be setup to not require any post-processing.

ahmedb72 · 09-07-2010, 06:52 AM

My question is: why top has less processes than ps output. I didn't find the answer in the man pages.

Plus, if I were experienced like u, I wouldn't need posting in the forum.

smoker · 09-07-2010, 02:22 PM

Top doesn't have less processes. Top is designed to show the "top" consuming processes, according to how you sort the list. You can specify how many lines are shown, and what the list is sorted by. Your original question asked how to display the top processes consuming the cpu. That is what "top" was designed for. Showing the top processes consuming the most X.