cfprefsd is sometimes using 100% CPU when scanning for peripheral devices using Core Bluetooth

Originator:kane.cheshire
Number:rdar://26194733 Date Originated:10 May 2016
Status:Open Resolved:
Product:OS X Product Version:10.11.4
Classification:Serious bug Reproducible:Sometimes
 
Summary:
Many people are experiencing 100% CPU usage when my app (MacID) scans for Bluetooth devices acting as a CBCentral using Core Bluetooth.

I am not able to reproduce this myself but I have been asking my users to collect diagnostic reports to forward on to you. As a result I can't say for sure which versions of OS X are affected but you should be able to see from the reports.

Users are reporting that the system slows down to the point of being unusable.

Steps to Reproduce:
1. On an affected Mac, set up a CBCentral to scan for all devices (do not scan for a specific CBUUID)
2. Note that cfprefsd is consuming high amounts of CPU

Expected Results:
The system should not use 100% of CPU

Actual Results:
The system uses 100% of CPU

Version:
10.11.4 (please see attached diagnostic reports also for other possible versions)

Notes:
I believe it's related to the writing of preferences to the com.apple.bluetooth.plist file but I am not sure enough to say that for certain in the report. I have many more reports that the bug reporter won't allow me to upload, also.

Comments


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