CentOS CPU usage

Question

Is there a way to get CPU usage in CentOS? I need to parse this information and graph it from a Perl script, so it should preferably be a simple tool that prints out one singular output.

Answer 1

atop @ http://www.atoptool.nl/ Will write to a log file, etc. Details here: http://www.atoptool.nl/systemreports.php

Answer 2

even easier, look at /proc/loadavg, it shows something like:

$ cat /proc/loadavg
0.37 0.67 0.68 1/312 8594

First three numbers are, "the number of cpu's you would need to handle the current load". Meaning that on multi core you can have a load of 5 without a problem. The three numbers are averaged over different intervals (1, 5 and 15 minutes, according to man uptime)

Answer 3

I actually use /proc/stat for this.. here's the important bits of the python I use for my dzen2 widget.

while(1):
    f = file("/proc/stat","r")
    fcon = f.read().split("\n")[0].split()
    new.user, unice, new.sys, new.idle, new.iowait = [
            int(x) for x in fcon[1:6] ]

    new.user += unice
    master.user = new.user - old.user

    master.sys = new.sys - old.sys
    master.idle   = new.idle - old.idle
    master.iowait = new.iowait - old.iowait

    maxval = master.user + master.sys + master.idle + master.iowait
    curval = master.user + master.sys + master.iowait

    old.copy(new)
    print (float(curval)/maxval) * 100 )
    time.sleep(1)

This prints a percentage use of the processor, by the second.

Wrong language, I know, but you should be able to get the gist of which columns of the output refer to what.

Answer 4

You can use top in batch mode with 1 (or more) iterations. Then use grep to parse through it.

$ top -b -n 1 | grep -2 "load average"

top - 12:08:31 up 14 days, 19:03, 26 users,  load average: 0.25, 0.45, 0.37
Tasks: 219 total,   1 running, 217 sleeping,   0 stopped,   1 zombie
Cpu(s):  4.2%us,  0.6%sy,  0.0%ni, 94.0%id,  1.0%wa,  0.0%hi,  0.3%si,  0.0%st

or

$ top -b -n 1 | grep "Cpu(s)\:"

Cpu(s):  4.2%us,  0.6%sy,  0.0%ni, 94.0%id,  1.0%wa,  0.0%hi,  0.3%si,  0.0%st

Further, you use can use awk to get a specific column and work from there.

$ top -b -n 1 | grep "Cpu(s)\:" | awk '{print $2}'

4.2%us,