Staying Cool with kernel_task

Here’s fun. Back in the Halcyon Days of 1982 one Richard McClintock made an interesting discovery – the origins of Lorem Ipsum (you know, the filler text you occasionally find padding out web pages and anywhere requiring placeholder material), thus:

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Mr McClintock – in a letter to Before & After magazine in 1994 – pointed out that the full passage was originally an excerpt from Cicero’s ethical treatise “The Extremes of Good And Evil” which was the number one hot bestseller of 45 B.C (probably). At some point in the sixteenth century – so the theory goes – an annoyed typesetter threw Cicero’s text into his press along with some filler, nonsense words in order to pad out enough text to mockup different types and fonts for a book, and then due to tradition and institutional laziness it stuck around for the next five hundred years and is still popping up today whenever You Just Need To Put Something There.

The thing is that it turns out there’s enormous value in having something on tap that you can use as a quick, reliable placeholder. It makes your life easier, you don’t have to constantly reinvent the wheel and go find new material to put into place, and it’s widely recognized for what it is; not actual content, but something to fill empty space until actual content can be substituted and you can go back to work.

But this isn’t my typeset blog; this is my macOS IT blog. And I’m not here to talk about placeholder text; I’m here to talk about placeholder processes. Hmm? What’s that? Well, I’m glad you asked. Meet kernel_task – the Lorem Ipsum of the macOS world.

When your Mac is running something particularly demanding then the chances are that whatever the “something” is will be using a lot of the CPU. You can see this in the Activity Monitor.app – sorting by % CPU will show you which apps or services are using the most system resources. The more CPU a process or program uses the more power it consumes, and the more heat it generates. And that’s fine; well-engineered computers and devices are built with heat tolerance and dissipation in mind (well, most are. I had a colleague who blew through three – yes, three – cheap PC laptops that all melted while my slightly more expensive PowerBook kept on ticking in support of the Sam Vimes Theory of Boots). Still, there are times and circumstances where it pays to have a way to throttle the activity of your computer to allow it to cool down – and this is that kernel_task does.

Simply put, it’s a process that the computer fires up whenever it decides that it’s running too hot, specifically to block other processes and applications from using the processor. Google Chrome wants to use a hundred percent of your CPU? Sorry; it’ll have to wait. kernel_task is using that right now, except all it’s doing is twiddling its thumbs, waiting for the computer to cool down while the fans run. Once things are back to an acceptable operating temperature then kernel_task frees up more and more resources until finally it all but disappears…

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