Save the climate with Xcode If one developer can change a room... Manuel @stuffmc Carrasco Molina @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 1 

Small things adds up. Consume less. —Each one of us can spare on its own gear —LG Ultrafine 5K: Up to 2kWh/day. 211 €/Year.1 —iMac Pro: Up to 370 W... Worst. —How can we have an impact on lots of people? —Apps! Yes we can (optimize) 1 https://www.lg.com/us/business/commercial-display/it-products/desktop-monitors/lg-27MD5KB-B 10 h * 200 W * 365 * 0.29 cts. Devs in this room responsible for being able to turn down a power plant? @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 2 

One line can change the code2 —And if can change the code, it can change the app —And if can change the App, then the world 2 https://youtube.com/watch?v=AmUUYo9o9eg @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 3 

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Your Code can change the world —Don't let energy optimization be the next testing —There's never enough time or money for testing —Same with Security... —Some security Company have no time for design @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 5 

Settings > Battery —Where the user will go if the battery is draining. —You don't want your app in this list. —It's like the losers list. @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 6 

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Activity of your app —Always an overhead (of the OS also) —Peaks in Energy usage when your app is used @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 9 

An app lifetimes —Sometimes resting —Sometimes doing more —Just like your iMac consuming more energy @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 10 

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The 4 !fantastics @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 12 

In General —Coalesce! Batch! —Think about the cost of starting the radios @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 13 

Processing —Avoid NSTimer. If at all, Coalesce with leeway —e.g. News App? Let the user refresh! @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 14 

Networking —Use earliestBeginDate3 from NSURLSessionTask —Balance between huge calls and many tiny calls —More network requests = more energy 3 earliestBeginDate Start the network load for this task no earlier than the specified date. @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 15 

Sending analytics —The best way to do it? Don't send analytics. —If you really can't quit the job where your company forces to do so... —Send them in batches: discretionary from NSURLSessionConfiguration 4 4 discretionary: Allows background tasks to be scheduled at the discretion of the system for optimal performance. @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 16 

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Location —start/stopLocation? requestLocation5! —Region Monitoring instead of checking location! —Lower the desired location accuracy6 —Don't forget to stop (when you get enough)! 6 e.g. to 3 KM if you can. 5 requestLocation: Request a single location update. @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 18 

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Graphics —Minimize screen updates —Review blur usage —Do you really need that animation? —OpenGL? Make your app mux-aware @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 20 

Video Player —Optimized from Apple —Don't show persistent UI Controls too long @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 21 

The Tools @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 22 

Energy Gauges ⚠ Not working on Simulator @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 23 

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Foreground/Background/Suspended @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 26 

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Instruments —Untethered Profiling! —Maybe environmental problems —Many Profiling Templates —Many Talks @ Conferences @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 29 

Energy Logs & Organizer —Similar to crash logs —Agregated Logs from your users —2 weeks of History —Data from TestFlight and App Store @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 30 

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References —WWDC 17: Writing Energy Efficient Apps —WWDC 18: What’s New in Energy Debugging —Work/Talk in Progress... —Questions? @stuffmc • Save the climate with Xcode, Feb '19, Cocoaheads 33