Get notified when something hits high % CPU in Activity Monitor?

Question

I wonder how can I let the Activity Monitor notify me when something hits a high CPU percentage (like 80-100%)? Sometimes when I open some app (e.g. Mail) and then close the window, the app is just running like crazy and draining my battery. But if I don't check the Activity Monitor myself, I would not notice some apps were running crazy like that. (The M2 MacBook Pros' fans are super quiet even when a process is taking 100% CPU)

Is there a way to let the Activity Monitor or something else notify me when an app or process takes a high CPU percentage? I'm not familiar with Shortcuts and Automator, so any kind of kind help would be much appreciated I'm also open to some third-party software if they can do the job right

Answer 1

The battery menulet will list apps using high amounts of CPU when you click on it.

It's completely expected that when you launch an app, then it's going to do a fair bit of work initially, but should settle down shortly. Killing a process while it's working may actually cause more problems, rather than fix them.

Mail might use high CPU while it is indexing the content. This shouldn't take long, but it is necessary, and stopping it will make things worse.

My Mail is currently using 0% CPU, despite being open constantly. (I suspect most people leave Mail running all the time, without closing the main window.)

100% is 1 core. An M2 has 8 cores. So 100% CPU is only 12.5% of the total. A process running at 100% shouldn't 'drain' the battery -- Apple Silicon is still very energy efficient.