Friday, September 29, 2023

Restless Mac Syndrome

Ventura's hourly wakes led me to discover something far far worse.

Friday, September 29, 2023 - Sam Rowlands

Hat tip to @Jeff_Tullin for the name inspiration. While researching the Ventura hourly wake issue, I accidentally stumbled onto this problem, which is potentially the worst sleep problem to date.

What is it

Restless Mac Syndrome is where the Mac wakes/sleeps every few seconds, resulting in 100s of wakes an hour. A typical Apple Silicon Mac will wake between 3.7 & 8 times an hour.

Restless Mac Syndrome only appears to affect Apple Silicon based Macs.

Causes

In general, attempting to make the Mac sleep all the way through without any insomnia. Because this issue is inconsistent and the lack of data, I've not been able to narrow much further.

I believe this is a bug in the macOS, or the PMU. Because of inconsistency, wakeType not being specified, and none of the wake scheduling values appear to exist (kIOPMSettingAutoWakeSecondsKey, kIOPMSettingAutoWakeCalendarKey, kIOPMSettingMaintenanceWakeCalendarKey & kIOPMSettingDebugWakeRelativeKey).

Without a working Intel Mac, I have been unable to confirm if these keys are simply not present on ARM or no longer used by the macOS.

Solutions

If you live in a studio apartment and a waking Mac disturbs your sleep, I currently have no solution for this, except to turn your Mac off over night.
Otherwise, for the time being it is more energy efficient to keep "Wake for Maintenance" on and use "Delay Background Tasks for Decades", which will reduce the wakes down to one every 70 ~ 85 minutes.
If the above options are set and it continue to experience Restless Mac Syndrome, check the file "/Library/Preferences/SystemConfiguration/com.apple.AutoWake.plist". Make sure that it exists and that the system can modify it.
Stuck bluetoothd can cause this, so force quitting it from Activity Monitor may help.

Notes

This issue has also highlighted a problem in Sleep Aid that I'm current investigating. The darkwake durations DO NOT tally up with the CPU time, in this case the difference can be as much 8 hours.