User1 User1 - 3 months ago 29
Linux Question

How to create a CPU spike with a bash command

I want to create a near 100% load on a Linux machine. It's quad core system and I want all cores going full speed. Ideally, the CPU load would last a designated amount of time and then stop. I'm hoping there's some trick in bash. I'm thinking some sort of infinite loop.

Answer

You can also do

dd if=/dev/zero of=/dev/null

To run more of those to put load on more cores, try to fork it:

fulload() { dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null & }; fulload; read; killall dd

Repeat the command in the curly brackets as many times as the number of threads you want to produce (here 4 threads). Simple enter hit will stop it (just make sure no other dd is running on this user or you kill it too).