How to get overall CPU usage (e.g. 57%) on Linux
LinuxBashUnixCpuLinux Problem Overview
I am wondering how you can get the system CPU usage and present it in percent using bash, for example.
Sample output:
57%
In case there is more than one core, it would be nice if an average percentage could be calculated.
Linux Solutions
Solution 1 - Linux
Take a look at cat /proc/stat
grep 'cpu ' /proc/stat | awk '{usage=($2+$4)*100/($2+$4+$5)} END {print usage "%"}'
EDIT please read comments before copy-paste this or using this for any serious work. This was not tested nor used, it's an idea for people who do not want to install a utility or for something that works in any distribution. Some people think you can "apt-get install" anything.
NOTE: this is not the current CPU usage, but the overall CPU usage in all the cores since the system bootup. This could be very different from the current CPU usage. To get the current value top (or similar tool) must be used.
Current CPU usage can be potentially calculated with:
awk '{u=$2+$4; t=$2+$4+$5; if (NR==1){u1=u; t1=t;} else print ($2+$4-u1) * 100 / (t-t1) "%"; }' \
<(grep 'cpu ' /proc/stat) <(sleep 1;grep 'cpu ' /proc/stat)
Solution 2 - Linux
You can try:
top -bn1 | grep "Cpu(s)" | \
sed "s/.*, *\([0-9.]*\)%* id.*/\1/" | \
awk '{print 100 - $1"%"}'
Solution 3 - Linux
Try mpstat
from the sysstat
package
> sudo apt-get install sysstat
Linux 3.0.0-13-generic (ws025) 02/10/2012 _x86_64_ (2 CPU)
03:33:26 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
03:33:26 PM all 2.39 0.04 0.19 0.34 0.00 0.01 0.00 0.00 97.03
Then some cut
or grep
to parse the info you need:
mpstat | grep -A 5 "%idle" | tail -n 1 | awk -F " " '{print 100 - $ 12}'a
Solution 4 - Linux
Might as well throw up an actual response with my solution, which was inspired by Peter Liljenberg's:
$ mpstat | awk '$12 ~ /[0-9.]+/ { print 100 - $12"%" }'
0.75%
This will use awk
to print out 100 minus the 12th field (idle), with a percentage sign after it. awk
will only do this for a line where the 12th field has numbers and dots only ($12 ~ /[0-9]+/
).
You can also average five samples, one second apart:
$ mpstat 1 5 | awk 'END{print 100-$NF"%"}'
Test it like this:
$ mpstat 1 5 | tee /dev/tty | awk 'END{print 100-$NF"%"}'
Solution 5 - Linux
EDITED: I noticed that in another user's reply %idle was field 12 instead of field 11. The awk has been updated to account for the %idle field being variable.
This should get you the desired output:
mpstat | awk '$3 ~ /CPU/ { for(i=1;i<=NF;i++) { if ($i ~ /%idle/) field=i } } $3 ~ /all/ { print 100 - $field }'
If you want a simple integer rounding, you can use printf:
mpstat | awk '$3 ~ /CPU/ { for(i=1;i<=NF;i++) { if ($i ~ /%idle/) field=i } } $3 ~ /all/ { printf("%d%%",100 - $field) }'
Solution 6 - Linux
Do this to see the overall CPU usage. This calls python3
and uses the cross-platform psutil
module.
printf "%b" "import psutil\nprint('{}%'.format(psutil.cpu_percent(interval=2)))" | python3
The interval=2
part says to measure the total CPU load over a blocking period of 2 seconds.
Sample output:
9.4%
The python program it contains is this:
import psutil
print('{}%'.format(psutil.cpu_percent(interval=2)))
Placing time
in front of the call proves it takes the specified interval time of about 2 seconds in this case. Here is the call and output:
$ time printf "%b" "import psutil\nprint('{}%'.format(psutil.cpu_percent(interval=2)))" | python3
9.5%
real 0m2.127s
user 0m0.119s
sys 0m0.008s
To view the output for individual cores as well, let's use this python program below. First, I obtain a python list (array) of "per CPU" information, then I average everything in that list to get a "total % CPU" type value. Then I print the total and the individual core percents.
Python program:
import psutil
cpu_percent_cores = psutil.cpu_percent(interval=2, percpu=True)
avg = sum(cpu_percent_cores)/len(cpu_percent_cores)
cpu_percent_total_str = ('%.2f' % avg) + '%'
cpu_percent_cores_str = [('%.2f' % x) + '%' for x in cpu_percent_cores]
print('Total: {}'.format(cpu_percent_total_str))
print('Individual CPUs: {}'.format(' '.join(cpu_percent_cores_str)))
This can be wrapped up into an incredibly ugly 1-line bash script like this if you like. I had to be sure to use only single quotes (''
), NOT double quotes (""
) in the Python program in order to make this wrapping into a bash 1-liner work:
printf "%b" \
"\
import psutil\n\
cpu_percent_cores = psutil.cpu_percent(interval=2, percpu=True)\n\
avg = sum(cpu_percent_cores)/len(cpu_percent_cores)\n\
cpu_percent_total_str = ('%.2f' % avg) + '%'\n\
cpu_percent_cores_str = [('%.2f' % x) + '%' for x in cpu_percent_cores]\n\
print('Total: {}'.format(cpu_percent_total_str))\n\
print('Individual CPUs: {}'.format(' '.join(cpu_percent_cores_str)))\n\
" | python3
Sample output: notice that I have 8 cores, so there are 8 numbers after "Individual CPUs:":
Total: 10.15%
Individual CPUs: 11.00% 8.50% 11.90% 8.50% 9.90% 7.60% 11.50% 12.30%
For more information on how the psutil.cpu_percent(interval=2)
python call works, see the official psutil.cpu_percent(interval=None, percpu=False)
documentation here:
> psutil.cpu_percent(interval=None, percpu=False)
>
> Return a float representing the current system-wide CPU utilization as a percentage. When interval is > 0.0
compares system CPU times elapsed before and after the interval (blocking). When interval is 0.0
or None
compares system CPU times elapsed since last call or module import, returning immediately. That means the first time this is called it will return a meaningless 0.0
value which you are supposed to ignore. In this case it is recommended for accuracy that this function be called with at least 0.1
seconds between calls. When percpu is True returns a list of floats representing the utilization as a percentage for each CPU. First element of the list refers to first CPU, second element to second CPU and so on. The order of the list is consistent across calls.
>
> Warning: the first time this function is called with interval = 0.0
or None
it will return a meaningless 0.0
value which you are supposed to ignore.
References:
- Stack Overflow: How to get current CPU and RAM usage in Python?
- Stack Overflow: Executing multi-line statements in the one-line command-line?
- https://stackoverflow.com/questions/6149006/how-to-display-a-float-with-two-decimal-places
- https://stackoverflow.com/questions/9039961/finding-the-average-of-a-list/9040000#9040000