Presented at https://www.meetup.com/Mobile-Apps-Performance-SF-Events/events/257929211/.

1. Developing Mobile Apps for
Performance
Swapnil Patel, Director of Software Engineering (Mobile),
Verizon Media
February 21st, 2019

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Users are complaining...but I did my job!
● I’m losing my DAUs but the app works perfectly.
● Performance tests passed 100% but user feedback is negative.
● Are we measuring performance KPIs correctly?

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Product teams...

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Security Engineers…

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What matters to users?

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● Latency (User perceived)
● Stability
● Battery
App Performance

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User perceived latency: Cold app launch

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Why is it taking so
long to launch
content?

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Cold app launch...keep it under 2000ms!
< 1500 ms I love this app!
> 1500 ms && < 5000 ms It should work!
> 5000 ms I’m done with this app!

10. Users may stop using your app
without sharing any negative
feedback

11. Measuring App Launch Performance

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Measuring app performance isn’t easy
● Hard to test and simulate real world scenarios
○ Controlled environment
○ High-end devices
○ Test hardware on low latency networks - test machines and
devices
○ Did you simulate 3G/4G network and real-world conditions?
● Needs continuous auditing
○ Different network bandwidth levels
○ Device capabilities
○ Regions or geo-locations

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App performance KPI: Cold App
Launch (iOS)
Credit: Devrim Tufan (Verizon Media), Scott Tury (Verizon Media)

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App performance KPI: Cold App
Launch (Android)
We want to report cold_start_display = Δdisplay with breakdowns
cpuElapsedTime appCreateDelta appCreateActCreateDelta actCreateStartDelta actStartResumeDelta actResumeDisplayDelta
Most apps report cold_start_* = Δd1 + Δd2 + Δd3
Credit: Devrim Tufan (Verizon Media), Scott Tury (Verizon Media)

15. Fine-tuning App Launch Performance

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What’s one thing I wish I knew before?
Fetch content in the
user’s viewpoint with a
single end point.

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What’s one thing I wish I knew before?
Fetch content in the
user’s viewpoint with a
single end point.
Reduce the number of
network calls to load
your home screen
faster.

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○ App cache
○ Background prefetch
○ Silent notifications
○ Network layer optimizations
○ User feedback (spinners,
animations…)
Nice to have…

19. Fetch content in the user’s viewpoint
with a single end-point, single
network call.

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Thanks!

21. Reach out
Swapnil Patel
Director of Software Engineering, Verizon Media
swapatel@verizonmedia.com
@patelsince1981
LinkedIn