Activity Monitor showing 80% cpu used, processes under 10%

[Ben J.]

Hi.

I've never seen this before; Activity Monitor shows lots of activity, and around 10-20% inactive. What's strange is that the processes showing most cpu usage are just using 5-10% or less.

I first noticed this when I plugged in a WD My Passport external USB drive to my newly aquired, second-hand macbook air. I unmounted it, and cpu usage dropped to around 10%. So, my first thought was that the drive was causing the strangeness. But after a restart, I saw the same thing again; high cpu usage without any process showing to be the cause of it - for a minute or two, and then it dropped to normal. And this time no external drive connected.

So, I figure it's some kind of drive indexing thing going on, and I'm not too worried. But I'm used to seeing the mds process or similar showing that they're the cause. I've never seen high cpu usage with no indication of what's causing it before.

Any thoughts?

 

[bogdanw]

I would check both disks for errors, from Recovery. Unmount the volumes before and "Repair volumes, then containers, then disks"
https://support.apple.com/en-us/HT210898

 

[Ben J.]

I would check both disks for errors, from Recovery. Unmount the volumes before and "Repair volumes, then containers, then disks"
https://support.apple.com/en-us/HT210898

Thanks. I did. Ran First aid on all volumes and both disks from Recovery. No errors, "seems to be OK". I'm looking at activity monitor right now; it's been showing total cpu in the nineties for 10 minutes now, with the top most process is around 5%.

Now, suddenly, it seems Activity Monitor is showing the culprit: triald and ca ten "mdworker_shared" processes keep coming up with % numbers that would make sense. (It must be said that I did copy a couple of hundred GBs to the external from my Mini last night, so assuming it is being indexed, it's no wonder it's taking so long today. I expect it to drop to normal at some point, like it has done before.)

It's still running at high cpu, and triald and the many mdworker_shared processes are sometimes showing, sometimes not. So maybe this is simply a question of Activity monitor not reflecting what's going on properly.

Added: There, it stopped. I'm back to 97% inactive cpu. I'm sure it lasted longer today because of the 200GB of new data.

 

[Bigwaff]

Most likely Spotlight was indexing the external disk. In Activity Monitor, make sure you have selected to view “All processes” rather than “My processes”.

 

[Ben J.]

Most likely Spotlight was indexing the external disk. In Activity Monitor, make sure you have selected to view “All processes” rather than “My processes”.

I know about indexing/spotlight/mds etc. I mentioned it more than once.
I do have AM set to show all processes.
So, the issue is; Activity Monitor is clearly not showing the process(es) using cpu - for long periods of time, like I explained.

 

[bogdanw]

So, the issue is; Activity Monitor is clearly not showing the process(es) using cpu - for long periods of time, like I explained.

You could try another process monitor, like
Vitals https://github.com/hmarr/vitals
bottom https://github.com/ClementTsang/bottom
Glances https://github.com/nicolargo/glances
Zenith https://github.com/bvaisvil/zenith

 

[Basic75]

Do "iostat 1" or "vm_stat 1" in Terminal.app show anything interesting? What about "top -o cpu"?

 

[Ben J.]

Do "iostat 1" or "vm_stat 1" in Terminal.app show anything interesting? What about "top -o cpu"?

Way above my Terminal competence, I'm afraid. I can do very simple stuff in Terminal, but this is greek to me. It only happens for a few minutes after mounting a external backup drive, and I only notice it if I'm watching Activity Monitor. It's only on my MB Air Monterey, and I don't back it up very often, and it doesn't seem to break anything, so I'm not going to worry about it. Thanks.