How can I determine the current CPU utilization from the shell in Linux?
For example, I get the load average like so:
cat /proc/loadavg
Outputs:
0.18 0.48 0.46 4/234 30719
7 Answers
Linux does not have any system variables that give the current CPU utilization. Instead, you have to read /proc/stat several times: each column in the cpu(n) lines gives the total CPU time, and you have to take subsequent readings of it to get percentages. See this document to find out what the various columns mean.
answered Aug 26, 2009 at 7:35
You can use top or ps commands to check the CPU usage.
using top : This will show you the cpu stats
top -b -n 1 |grep ^Cpu
using ps: This will show you the % cpu usage for each process.
ps -eo pcpu,pid,user,args | sort -r -k1 | less
Also, you can write a small script in bash or perl to read /proc/stat and calculate the CPU usage.
10 Comments
Dénes Tarján
We tried, and "top -b -n 1" gives very inaccurate results. "top"'s first iteration is very approximative, can give 10 percent instead of 60.
Christian
Would increasing the number of iterations with -n > 1 be more precise? Have you tested this case?
BozoJoe
top's calculation of %CPU is different from ps's calc of %CPU. see this answer unix.stackexchange.com/questions/58539/…
jarno
LC_ALL=C top -b -n 1 |grep ^%Cpu gives CPU stats for me in Ubuntu.
CpnCrunch
@jarno this is the answer to "How can I determine the current CPU utilization from the shell" (assuming that means for the entire cpu(s)). The command gives the idle % and you can subtract from 100 if you want cpu utilization.
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The command uptime gives you load averages for the past 1, 5, and 15 minutes.
answered Jan 10, 2013 at 13:11
Comments
Try this command:
cat /proc/stat
This will be something like this:
cpu 55366 271 17283 75381807 22953 13468 94542 0
cpu0 3374 0 2187 9462432 1393 2 665 0
cpu1 2074 12 1314 9459589 841 2 43 0
cpu2 1664 0 1109 9447191 666 1 571 0
cpu3 864 0 716 9429250 387 2 118 0
cpu4 27667 110 5553 9358851 13900 2598 21784 0
cpu5 16625 146 2861 9388654 4556 4026 24979 0
cpu6 1790 0 1836 9436782 480 3307 19623 0
cpu7 1306 0 1702 9399053 726 3529 26756 0
intr 4421041070 559 10 0 4 5 0 0 0 26 0 0 0 111 0 129692 0 0 0 0 0 95 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 369 91027 1580921706 1277926101 570026630 991666971 0 277768 0 0 0 0 0 0 0 0 0 0 0 0 0
ctxt 8097121
btime 1251365089
processes 63692
procs_running 2
procs_blocked 0
More details:
http://www.mail-archive.com/[email protected]/msg01690.html http://www.linuxhowtos.org/System/procstat.htm
answered Aug 28, 2009 at 12:04
Comments
Maybe something like this
ps -eo pid,pcpu,comm
And if you like to parse and maybe only look at some processes.
#!/bin/sh
ps -eo pid,pcpu,comm | awk '{if ($2 > 4) print }' >> ~/ps_eo_test.txt
2 Comments
Dušan Brejka
And if you'd like to sum CPU usage by process name (for example if you're running chrome that spawns dozens of processes with the same name), you can use
ps -eo pcpu,comm | awk '{if ($1 > 0.1) arr[$2]+=$1} END {for (key in arr) printf("%s\t%s\n", arr[key], key)}'.jarno
@DušanBrejka You may have to add
LC_ALL=C for awk, at least if it is mawk depending on your locale.You need to sample the load average for several seconds and calculate the CPU utilization from that. If unsure what to you, get the sources of "top" and read it.
2 Comments
Joel
Thanks - but there is no way to calculate CPU utilization from the load average.
elcuco
Actually there is, again, read the source. I think, that the load average is the derivative of the CPU utilization, to you need to make some sort of integral to get the CPU utilization. No better way to explain this - just use the source Luck.
vmstat, as a bonus it works on BSDs as well.