Sometimes people want or even need to produce some CPU-usage without big effort i.e. for testing issues.

The following article describes an easy way to realize that using the Terminal in Mac OS X.

System

Hardware

Software

• CPUPalette.app to display CPU usage
• yes command to generate some stress

CPUPalette.app is not installed on Mac OS X by default – while it is part of the free Apple Developer Tool-Set. If you are not willing to install CPUPalette – consider using Activity Monitor.app which is installed in

/Applications/Utilities/Activity Monitor.app

CPU Graphs

Idle

Which means – besides the basic processes i have Firefox, iTunes, RSS-Reader, Thunderbird runnig as i am writing while testing

1 CPU Core

Now – lets start.

• Open Terminal.app
• Enter: yes > /dev/null
• Press Enter

Lets check the CPU

2 CPU Cores

Now open a new Terminal window and do the re-do the above

Lets check the CPU

3 CPU Cores

Now open a new Terminal window and do the re-do the above

Lets check the CPU

4 CPU Cores

Now open a new Terminal window and do the re-do the above

Lets check the CPU

Lets take a look into Activity Monitor.app

and

Conclusion

Using the yes command and redirecting it to the black hole is a very simple but effective method to generate some CPU usage without big effort.

My 3 year old Mac Pro – first generation – easily handled the task – Mac OS X was acting without issues as expected. The temp increased slowly from 33 degree celcius up to 40 at the end.

Tags: activity monitor, cpu, cpu-cores, cpupalette, mac pro, stress test, yes, yes > /dev/null