Xcode 6 + iOS 7.1 sim slowness?

vicwomg · October 9, 2015, 9:06pm

Folks, looks like there’s an active pull request for the fix for this, but fb is disowning instruments-without-delay and recommending that someone just forks the project. I have tried the fix and it works, but it’s a bit hairy since new permissions issues in Xcode 7 require some plist editing to work.

Source:

I took notes of my steps to implement it the fix:


cd ~
git clone https://github.com/lawrencelomax/instruments-without-delay.git
cd instruments-without-delay/
git checkout xcode7-quirks
./build.sh

Next, you’re going to want to edit the plist file at:
/Applications/Xcode-7.0.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/Developer/Library/LaunchDaemons/com.apple.instruments.deviceservice.plist

And replace it with the one from the url below. Be sure to replace the paths ("/Users/lawrencelomax/src") with your own build dirs:

gist.github.com

https://gist.github.com/lawrencelomax/03da6538a0cce1b60c47/

Instructions.md

instruments-without-delay uses the ```DYLD_INSERT_LIBRARIES``` environment variable to shim from the instruments command line all the way down to ```ScriptAgentShim``` which is the iOS Simulator service responsible for interfacing UIAutomation JavaScript with the native ```UIAutomation.framework```. It uses a stack of shims, starting at the ```instruments``` executable, going through ```Simulator.app```. It is an essential part of ios-driver as it removes a pesky 200ms delay that drastically slows down the process of executing end-to-end tests. This is a fixed cost that would occur on every command.

Other than a few things being moved around and renamed in Xcode 7, there is the new issue of the codesigning of the Simulator app that triggers ```amfid``` whenever an unsigned image is loaded. This essentially means that we can't use ```DYLD_INSERT_LIBRARIES``` on the Simulator Process with ```SimShim```

It is however, possible to inject these environment variables at the launchdaemon level. There is a plist for ```DTServiceHub``` at: ```/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/Developer/Library/LaunchDaemons/com.apple.instruments.deviceservice.plist```

It can be modified to inject the ```DTMobileISShim``` (see the attached plist). However, this is less than ideal as this requires modifying the Xcode binary.

com.apple.instruments.deviceservice.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>EnableTransactions</key>
	<true/>
	<key>EnvironmentVariables</key>
	<dict>
		<key>DYLD_INSERT_LIBRARIES</key>
		<string>/Users/lawrencelomax/src/instruments-without-delay/build/DTMobileISShim.dylib</string>

This file has been truncated. show original