Comment by varenc | Hacker News Reader

Comment by varenc | Hacker News Reader

On mac OS, Activity Monitor itself causes WindowServer CPU usage to spike. This is the "observer effect".

To test, just open a terminal and compare a few samples of `ps aux | grep WindowServer` with Activity Monitor open and with it closed.

Mine averages 7-11% with Activity Monitor closed and 20-40% with Activity Monitor open. It's even more noticeable if your refresh rate is set to "Very Often". Closing Activity Monitor brings the WindowServer CPU back to normal.

As other have noted, this site provides no evidence. The keystone daemon is not running in the background constantly. When it does run, it's plainly visible and not "hiding itself". According to the launchd job config located at `/Library/LaunchAgents/com.google.keystone.agent.plist` my keystone process is set to run itself every 3623 seconds. Probably randomized to avoid the thundering herd problem. When it does run it checks for updates, often downloading new ones, and then quits.

This is because since macOS Catalina Activity Monitor did something to itself to make itself spend half a core just updating its table view and literally nobody who works on it (which I suspect is <1 person) understands that a monitoring tool that uses more CPU than the thing it is meant to monitor is absurd. I have seriously considered rewriting it multiple times and if the app stays like it is one day I probably will.

Please do! I like Mac, but I yearn a quality of 1st and 3rd party Windows tools. Task manager is nicely readable and lightweight, and process explorer is a godsend.

Meanwhile Activity Monitor updates once per 30 seconds when the system is under load.

Agreed! I recently used Windows for the first time in years, and was impressed by two of the built in monitoring programs. It was dead simple to actually get a global view of all file system activity and the processes responsible. Mac’s first party "fs_usage" tool is far less usable. As an example, there’s no way to prevent it from truncating long paths.

Any reason you don’t use a terminal tool like htop?

I do use htop occasionally; however, I am not really a fan of keeping around a terminal for something that could be a well-integrated native app. Plus htop is missing a lot of information Activity Monitor has, as well as the ability to do things like run sample or spindump.

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