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Decrease build time and application size by 60%

Decrease build time and application size by 60%

This is the presentation of the talk I gave in the MAD meetup on 15th April. This talk basically explains different tricks & tweaks to decrease your application size and your Gradle build time.

If you have any queries or any feedback, hit me on twitter: https://twitter.com/kevalpatel2106

Keval Patel

April 15, 2017

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  1. Agenda - What is Gradle? How does it work? -

    Why decrease application build time? - How to decrease application build time? - Introduction to APK analyzer - Why is APK size so important? - How to trim your APK? 2
  2. What is Gradle? - Very powerful build system - Written

    in Groovy & Java - Open source - Flexible dependency management - Task based 3
  3. What Gradle does? - Building .dx files from java source.

    - Merge all the resources and assets. - Generates .apk from the source code. 4
  4. Why you should care about your build time? Let’s say,

    - You are generating 15 clean builds every day. - Each build takes 3 minutes to generate. - Total time: 15 * 3 = 45 mins. - If you work for 8 hours a day, that’s almost 10% of your work time. - That’s about 4 hours a week !!! 6
  5. Less build time More time for productive stuff Better app

    with less bugs Happy users Less Build Time = More Productivity Why you should care about your build time? 7
  6. Benchmarking with I/O’16 Application - Open source (https://github.com/google/iosched) - 25+

    dependencies and third party libraries - 41538 method references 8
  7. - Two modules: - android: Contains android application classes and

    resources. - server: Contains codebase for backend server. - Minimum SDK - 16 - Target SDK - 22/23 - 9 different languages Benchmarking with I/O’16 Application 9
  8. Gradle build life cycle 1. Initialization 2. Configuration 3. Execution

    - Initialize resources - Start daemon thread - Figure out what to build - Evaluate your build.gradle script - Configure all the plugins - Evaluate the task graph. - Runs all the previously evaluated task - Build the application. 10
  9. --profile will tell gradle to measure the time taken to

    execute each task and dump that data into HTML file. --profile your gradle build time $ ./gradlew assembleDebug You can find that report under /[your project dir]/build/reports/profile directory. Sample 11 --profile
  10. - --dry-run tells gradle to evaluate the project but don’t

    run any task. - The last phase of the life cycle (execution phase) won’t get executed. - Tells us the time required by Gradle to configure the project and to start the build. Measure time required to configure 14
  11. Gradle Daemon - Gradle runs on the Java Virtual Machine

    (JVM) and uses several supporting libraries to be load at initialization time. That's why it's slow to start. More info : https://docs.gradle.org/current/userguide/gradle_daemon.html - Gradle Daemon is a long-lived process that will run in the background. - Avoid the cost of JVM startup for every build, - Able to cache information about project structure, files, tasks, and more in memory. 18
  12. Commands for Gradle Daemon - To enable daemon for gradle

    build use --daemon. - To get a list of running Gradle Daemons and their statuses use the --status command. - To stop daemon use --stop command. 19 More info : https://docs.gradle.org/current/userguide/gradle_daemon.html
  13. Gradle Daemon $ ./gradlew assembleDebug --dry-run --configure-on-demand --daemon --profile Initialization

    time decreased by 4.1 seconds than before after running the build for the second time. Speed improvements will apply for subsequent builds. 20
  14. Dex in the process - “Dex in process” is a

    process that allows to run multiple dex processes to run within the single VM that is also shared with the gradle. - Requirement: - Build tool version 23.0.2 or above. - Android Studio 2.0 or above. 22
  15. Dex in the process - Multiple dx processes runs on

    different VM instances. - These increases build time as each dx has to pass data between different VM instances. - Requires less per VM heap size as single VM is hosting only single dx process. https://www.youtube.com/watch?v=-SY5nkNVUn0 23
  16. Dex in the process Starting from AS 2.0, - All

    these dx processes run in the single VM and that VM is also shared with the gradle. - Require higher hip size to run as much as possible dx processes in a single instance. https://www.youtube.com/watch?v=-SY5nkNVUn0 24
  17. Dex in the process Add below line in your /gradle.properties

    file to re-configure the heap size. org.gradle.jvmargs= -Xmx3072m -XX:MaxPermSize= 512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF -8 - Select the best suitable heap size for your system based on the amount of RAM available. - Generally, after 4GB, any further increase in heap size won’t affect the build time. 25
  18. Enable parallel builds - If you have multiple modules in

    you project, then by enabling this, gradle can run build operations for independent modules parallelly. - Gradle will only build modules parallelly if two modules are not interdependent. Google I/O project doesn’t have multiple modules, building parallel won’t make much difference. 26
  19. Enable parallel builds Add below line in your /gradle.properties file

    to enable parallel builds. org.gradle.parallel=true 27
  20. Other small things to remember… - Avoid heavy computations, like

    increasing the version code from git commits count or downloading some files from URL while building the project. - Always use latest gradle version. (Current is 3.4.1) - Don’t use dynamic dependency. compile 'com.android.support:appcompat-v7:23.0.+' compile 'com.android.support:appcompat-v7:23.0.1' 28
  21. TL;DR #Enable daemon org.gradle.daemon=true # Try and find out the

    best heap size for your project build. org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8 # Modularise your project and enable parallel build org.gradle.parallel=true # Enable configure on demand. org.gradle.configureondemand=true - Add below line in your /gradle.properties. - Modularize your project. 29
  22. Why APK size is so important? - Because you want

    to get your next billion users. - Mobile devices have limited amount of battery, limited storage, limited processing power, limited RAM, limited internet connectivity… - Currently, more than 11000 android devices are out in the market and most of them are having low-end configurations. - Two key things that are precious to every smartphone user, 1) Storage. 2) Network connectivity. 31
  23. Storage - Most low-mid range devices have 8GB to 16GB

    internal storage. - The less storage your application uses, the more free space user gets to store their videos and images. - You don’t want your user to uninstall your application because of “Storage out of space” notification. 32
  24. Network connectivity - Most of the android users are from

    developing countries (like India, Brazil or countries in Africa) where they have very limited 2G/3G connectivity. - If your application is large in size, it will take a longer time to download the application. - Most of the users have limited amount of data. - Every byte user uses to download the application, will affect your user’s wallet. 33
  25. APK Analyser Provides immediate insight into the composition of your

    APK. Features: - View file size and the download size of the APK - View AndroidManifest.xml - View resources - View dex files and method counts for each dex files. - Compare two APK files. 35
  26. 36

  27. Breakdown of APK - APK file mainly contains 3 major

    components which utilize the maximum amount of size in whole apk package: 1. classes.dex - dex file which contains bytecode of your java classes. 2. res - Contains images, icons and raw files, menu files, and layouts. 3. resources.arsc - Holds all the value resources. This resource contains strings, dimensions, styles, integers, view ids etc. 37
  28. Proguard - A Java class file shrinker, optimizer, obfuscator, and

    preverifier. - It detects and removes unused classes, fields, methods, and attributes. It optimizes bytecode and removes unused instructions. - It renames the remaining classes, fields, and methods using short meaningless names to prevent reverse engineering of your apk file. 39
  29. How to apply proguard? - You have two default proguard

    files bundled in your SDK that you can apply. - proguard-android.txt - contains light-weight proguard rules. - proguard-android-optimize.txt - contains very aggressive obfuscation and shrinking rules. release { //Enable the proguard minifyEnabled true proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), "proguard-rules.pro" } 40
  30. Enable “shrinkResources” - Many unused images and strings (e.g. resources

    for sign in with google button images) those are not used in your entire application. - Most of these unused images/resources are from third party libraries (e.g. Google Play Services). 43
  31. Enable “shrinkResources” - Remove all the resources (images/strings), those are

    not used anywhere in the project. - To enable this in your build, add below lines: release{ //... //... shrinkResources true //... } 44
  32. Set “resConfigs” - Libraries like Google Play Services contains resources

    from different locales. - Your application does not support all locales. - Provide the list of locales your application supports and “resConfigs” will remove all the resources for not supported locales. defaultConfig { //... //strip other than english resources resConfigs "en" } 45
  33. Convert your png images to webp - webp is image

    format like png but having less size than png image with the same quality. - webp is natively supported by Android since the beginning. So you can load webp images in ImageView same as other raster images. - Android Studio 2.3 provides a built-in tool that can convert your png images to webp. 46
  34. How to convert png images to webp? - Right-click on

    the image and select “Convert to webp”. - Select quality of the output image. - Select whether to convert transparent images to webp or not. - Hit “OK”. That’s it!! 47
  35. Final comparison * This are the results from the current

    version of the Anti-Theft apk. So, numbers are different than previous slides. 50
  36. TL;DR • Enable proguard in your project by adding following

    lines to your release build type. • Enable “shrinkResources”. • Strip down all the unused locale resources by adding required resources name in “resConfigs”. • Convert all the images to the webp or vector drawable. 51
  37. How to decrease your Gradle build time by 65%? http://bit.ly/2jvi9XB

    How you can decrease application size by 60% (In only 5 minutes)? http://bit.ly/2mWQQIc 52 References: