Overview
yeetd is a lil' daemon that watches for specific CPU-intensive Simulator processes and stops them in their tracks! yeetd runs on both macOS Ventura and Sonoma.
Why?
Due to some nifty missing entitlement issues in the iOS Simulator, the Xcode 15 release has some very nasty CPU issues when running unit or UI tests. Until Apple releases an update addressing this issue, CI testing times can sometimes be up to two or three times longer than Xcode 14 running the same tests.
What are the processes?
During my testing, I found that a handful of *Poster processes (e.g. AegirPoster, ExtragalacticPoster, KaleidoscopePoster, etc.) are missing an entitlement, resulting in SpringBoard having a Very Bad Day™ every time it tries to talk to them. SpringBoard really likes talking to the Poster processes, which wastes a CPU core or two. apsd also has issues because it believes it needs to activate itself (I could be mistaken, but I don't think that the Simulator can activate itself with APNS). By default, yeetd will not kill apsd in the Simulator because it causes issues when testing push notifications with the simulator. If you're still seeing performance issues/timeouts when running yeetd, try running defaults write dev.biscuit.yeetd killapsd true to tell it to kill apsd.
Installation
NOTE: while I've tested this tool extensively, I cannot promise it will fix Xcode in every case. Please test this tool in a testing CI environment before deploying it a production CI environment!
You can find a package in the Releases section of this repo or build the tool from scratch. If you install the package, it will automatically load yeetd as a LaunchDaemon.
I've included a helper script that I use to build, package, and notarize macOS packages. To use it, you'll need the following setup:
- A Developer ID Application AND Installer certificate from the Apple Dev Portal.
- An app specific password to interact with the notarization service.
To build the signed package, ensure code signing is correctly set up in the Xcode project and run the following command:
./build-installer.sh "<your signing identity>" "<app store connect account>" "<team ID>" "<app specific password>"Extras
I've included an additional helper script named prewarm_simulators.sh with the installer. There's a fun "Simulators sometimes take 1-30 minutes to boot for the first time" bug that this script addresses. This script only needs to be run once when creating a new CI template image.
Apple Folks
Please check out FB13187399 and release a fix ASAP ❤️
Thanks
Thanks to Saagar for helping me write goofy yet fun code at 2AM and for everyone who helped test & vet this solution! If you have any questions or comments, feel free to open an issue or reach out to me at @[email protected]