PSA: Keep Time Machine disks out of your Finder sidebar | Hacker News Reader

PSA: Keep Time Machine disks out of your Finder sidebar

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62 pointscjv18 comments

There’s nothing in that thread that supports the assertion that this is taking ‘half a core’.

The Finder sample shows it taking less than 10% of the wall-clock time of one (mostly idle) thread, and it doesn’t seem likely that WindowServer is spending another 40%+ of a core in response.

The thread focuses on the problematic code, not the performance impact it has. The second (collapsed) __CFRunLoopRun in the sample screenshot contains all the resultant drawing happening in-process, with which Finder used about 20% of the CPU. WindowServer was using about ~25% to keep up.

You’d think Apple, having developed the thing, would have used Core Animation for this.

Especially since Apple re-wrote the Finder for the OS X release right after the one that introduced Core Animation. Maybe they were trying to be a bit conservative with the Cocoa Finder rewrite and were focused on simply ditching the Carbon APIs while preserving as much of the application's behavior and internal structure as possible, rather than more thoroughly modernizing the app. But the fact that it still hasn't been modernized in this way for more than a decade sounds like Apple's macOS developers a Microsoft-style fear of touching core components of the OS.

Maybe there’s a dependency that prevents them from using core animation there.

In which case not animating may be the correct response.

My bet is you want the finder to have the least amount of dependencies, so it can still work even if a lot of things are broken in the OS.

Yeah, that does seem like a rookie mistake.

Does the extra CPU use typically cause any visible issues to the user, though? User impact is what's most important here. I don't particularly care if my CPU works a little harder than it needs to for a few seconds, as long as I can still do what I want on the machine without issue.

The animation spins for as long as the backup runs, which for me was about ten minutes an hour.

I see. Does it disrupt your use of the computer in any way? In other words, if you weren't looking at a CPU monitor, would you notice?

Using half a core for 10 mins per hour will likely have a material effect on battery life. Unless someone instruments exactly how much, it’s hard to say, but this doesn’t seem like a hand-wave.

It would make the fans come on occasionally, which was annoying. But in general I am of the opinion that apps shouldn’t be using processor time when they’re not doing anything useful. This is why I always have a CPU monitor open: it quickly lets me know when something starts doing unexpected things.

Sounds quite long, actually. I’ve recently found that external SSDs have become affordable enough for me to use them for backups.

Good on you for digging in and finding the issue, by the way.

Great.

And how do I make this change? What setting do I have to check or un-check? Or is it a defaults(1) thing?

Proviso: I would like to keep my "Hard disks" and "External disks" visible.

You’ll have to drag the external disk for your Time Machine backup out of the sidebar. Collapsing the section does not work, unfortunately.

When they still had iTunes the same thing happened with the colored bar that spins showing sync activity, using 40% of a cpu. I’ve filed bugs on it, they don’t seem to care.

Is this the "Apple Quality Experience" I keep hearing about?

Seems like an intern's first task that wasn't double checked(in arguably one of the most important parts of the OS).

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