Simple tips on how to speed up your Android builds. This talk is inspired by Stefan Oehme ( Gradle, Lead Developer) talk on “IMPROVING ANDROID BUILD PERFORMANCE” - Droidcon Berlin 2018

1. Gradle
optimisation
Speed up kotlin/android builds
Bartosz Kosarzycki
@bkosarzyckiJuly 26, 2018

2. Gradle build phases:
- Initialization
- Configuration
- Execution

3. +

4. How can we solve this?
- Modularization =>
Compile avoidance
- Decoupled code =>
Faster incremental builds

5. Increase memory
which is available to
Android Studio

6. Increase memory
Default: 1246 MB

7. Check gradle
wrapper version

8. Currently the newest
version is: 4.8.1
Check gradle version
{project_home}/gradle/wrapper/gradle-wrapper.properties

9. - In 4.8.1 disable Google’s experimental “Configure on demand”
* What went wrong:
A problem occurred evaluating project ':repository'.
> Failed to apply plugin [id 'com.android.library']
> Configuration on demand is not supported by the current version of the Android Gradle plugin since you are using
Gradle version 4.6 or above. Suggestion: disable configuration on demand by setting
org.gradle.configureondemand=false in your gradle.properties file or use a Gradle version less than 4.6.
Check gradle version
- “instant run” is lost due to Android Studio & gradle incompatibility

10. Do not mix
Java/Kotlin files in
one module

11. Solution:
Extract legacy Java files into a
separate module if you cannot
convert them to kotlin

12. Enable
build caches

13. Solution:
org.gradle.caching=true
Info:
https://developer.android.com/studio/build/build-cache
Clear cache: ./gradlew cleanBuildCache
{project_home}/gradle.properties

14. Prevent
Crashlytics
from ruining your
incremental builds

15. Fix for Crashlytics
buildTypes {
debug {
debuggable true
minifyEnabled false
shrinkResources false
ext.enableCrashlytics = false
ext.alwaysUpdateBuildId = false
}
}

16. Use offline
mode
when no new
dependencies are
added

17. Disable
multidex

18. Disable multidex
android {
defaultConfig {
multiDexEnabled false
}
}
// MIN API LEVEL : 21

20. Predex
libraries

21. Predex libraries
android {
dexOptions {
preDexLibraries true
}
}
Predexing builds dex file out of libraries so it can be used in
incremental builds (not building dex files each time for libraries). Using
this feature increases clean build time.

22. Avoid
annotation
processors
especially those
breaking incremental
builds

23. Solution:
- Use gradle > 4.7
- Use only Annotation Processor which
do support incremental builds
- Google’s data-binding AP does NOT
support it (work in progress)
https://github.com/gradle/gradle/issues/5277
Incremental Annotation Processors:

24. Keep
kotlin lang
& libraries
up-to-date

25. Enable D8
Next generation dex
compiler

27. Android R8 compiler
is still experimental
(July 2018)

28. Source: Droidcon NYC 2016 - Lightning fast Android builds with Gradle + Buck

29. BAZEL builds (Google):
$> brew install bazel
- different project structure
- create WORKSPACE file with sdk info
- create BUILD file with

31. Use
gradle
profiler

32. - download repository here + docs
- compile
- make an alias for ‘gradle-profiler’
Install gradle profiler:
> ./gradlew installDist
cp ./build/install/gradle-profiler/* ~/custom/gradle-profiler
alias gradle-profiler='~/custom/gradle-profiler/bin/gradle-profiler'

33. Profile build performance:
> ./gradlew clean
> gradle-profiler --benchmark --project-dir . assembleDebug
> open ./profile-out/benchmark.html
- from inside project’s directory:

36. Gradle profiler
with FlameGraphs

37. - Linux-only (currently)
- Download ‘honest-profiler’ &
‘flame-graph’
Gradle-profiler with FlameGraph
> gradle-profiler --profile hp --hp-home ~/custom/honest-profiler
--fg-home ~/custom/flame-graph --project-dir . assembleDebug

38. Use
gradle
scans
http://scans.gradle.com

39. Gradle scans:
$ ./gradlew build --scan
BUILD SUCCESSFUL in 6s
Do you accept the Gradle Cloud Services license agreement
(https://gradle.com/terms-of-service)? [yes, no]
yes
Gradle Cloud Services license agreement accepted.
Publishing build scan...
https://gradle.com/s/czajmbyg73t62
- uses cloud web services

43. Future:
use
static/binary/
prebuilt libraries ?

44. Android Studio Preferences

45. Android Studio Preferences

46. Convert Android
Traceview
into flamegraphs

47. Convert Android Traceview...

48. Into Flamegraph
LINK

49. Links / References
- Stefan Oehme / Gradle, Lead Developer - Droidcon Berlin 2018 - “IMPROVING ANDROID BUILD
PERFORMANCE” / Intermediate / Best Practices / Code Quality / Talk - link
- Speed-up Android builds - link
- TraceView into FlameGraph - link
- Gradle-Profiler - link

50. QUESTIONS?