How to generate CPU load on Linux server

You can download and install the "stress" utility... It allows you generate CPU, Memory, Disk and IO load from the command line.

Homepage: http://people.seas.harvard.edu/~apw/stress/

FAQ: http://people.seas.harvard.edu/~apw/stress/FAQ

I prefere floating point ops:

for i in `seq 64`; do perl -e '$z=time()+(10*60); while (time()<$z) { $j++; $sqrt = sqrt($j) for (1..9999); }' & done

Be aware of your CPU number :-)

This is something I frequently want to do. But I don't have a good way of doing it. I just write a small Perl script that will just loop for as many seconds as I want.

E.g. (for 10 minutes):

perl -e '$z=time()+(10*60); while (time()<$z) { $j++; $j *= 1.1 for (1..9999); }'

Of course if you have n processors you might want to add a bash loop to create that many processes:

#!/bin/bash
# e.g. for 4 processors
for i in 1 2 3 4; do
    perl -e .... &
done
wait

cpuburn

"How do I run a command, and have it abort (timeout) after N seconds?"

I recommend using stress-ng, it has a lot more features than stress and can exercise far more of the operating system.

http://kernel.ubuntu.com/~cking/stress-ng/

Here is a pure shell (at least bash & ksh) way that I already posted as a reply to a similar question here

# Usage: lc [number_of_cpus_to_load [number_of_seconds] ]
lc() {
  (
    pids=""
    cpus=${1:-1}
    seconds=${2:-60}
    echo loading $cpus CPUs for $seconds seconds
    trap 'for p in $pids; do kill $p; done' 0
    for ((i=0;i<cpus;i++)); do while : ; do : ; done & pids="$pids $!"; done
    sleep $seconds
  )
}