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Spotify flashes non-stop (the left sidebar and the bottom control strip, but interestingly not the main app window).

> Quartz Debug: There are some apps that reduce your battery life in an insidious way where it doesn’t show as CPU usage for their process but as increased WindowServer CPU usage. If your WindowServer process CPU usage is above maybe 6-10% when you’re not doing anything, some app in the background is probably spamming 60fps animation updates. As far as I know you can only figure out which app is at fault by getting the Quartz Debug app from Apple’s additional developer tools, enabling flash screen updates (and no delay after flash), then going to the overview mode (four finger swipe up) and looking for flashing. This same problem can also occur on Linux and Windows but I don’t know how much power it saps there.

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If you're using Quartz Debug, you probably want to set these as well:

  defaults write com.apple.QuartzDebug QuartzDebugPrivateInterface -bool YES
  defaults write com.apple.QuartzDebug QDDockShowFramemeterHistory -bool YES
  defaults write com.apple.QuartzDebug QDDockShowNumericalFps -bool YES
  defaults write com.apple.QuartzDebug QDShowWindowInfoOnMouseOver -bool YES

The first one lets the window list work, which Apple in its infinite wisdom has decided you as a non-Apple engineer don't need. The middle two are things you can set from inside the app but show useful things in the dock icon. And the last lets you identify which app a window belongs to (press ⌃⌥ while hovering over it), which is very useful when you have a random thing pop up and you don't know how to get rid of them.

Thank you!

An app that was going to make it on my list was Anesidora, which is a native macOS Pandora player which of all the many music streaming apps I've tested including Apple Music, is the only one which uses less than 10% CPU total including on WindowServer and coreaudiod. Unfortunately since I got it the author seems to have removed it from the app store. There's some other native Pandora apps that might have low resource usage but I haven't tested them. I switched to Pandora for my music streaming mainly because of Anesidora, and luckily I still have it downloaded. Anesidora still redraws when it's hidden, but only once every second, and it uses lower CPU itself and in coreaudiod than other players.

Have you tried https://hermesapp.org?

No I hadn't seen that. It appears to have been unmaintained even longer than Anesidora but at least it's open source.

You might be able to find it out without installing Quartz Debug by using the system's DTrace probes, most of Apple's stuff already comes pre-instrumented.

Haven't tested or validated that it can be done though, just an idea...

Add Discord to the list of apps that cause WindowServer cpu% to spike.

The issue with Discord is if the message compose box is focused the cursor keeps flashing and redrawing a big tile of the screen even in the background, manually defocusing the message box fixes this. This is also something Discord could easily fix I think.

…if they knew about or cared, which I suspect they certainly didn't until now. Based on the number of things on my screen that force 60 FPS drawing, there's many developers who never notice :(

Apple should really consider surfacing this info to users and outing offending apps, much as they do with high energy consumption currently.

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