This document summarizes a presentation about improvements to Gradle's daemon feature in version 3.0. The daemon runs as a long-lived background process to speed up builds. New features include the daemon being enabled by default, being more robust on Windows, and integrating with build scans. The daemon also becomes more resource-aware and intelligent over time through machine learning. Users are encouraged to try the new daemon features and provide feedback to further improve Gradle's performance.

1. Gradle Summit
Gradle 3.0: Unleash the Daemon!
Eric Wendelin
2016

2. Eric Wendelin
@eriwen

3. Long-lived Background Process
Client/Server communicating over TCP locally
Listens for and executes Build Actions
Daemon in a nutshell

4. Daemonstration

5. 2nd build typically
15-75% faster

6. faster the more
you use it
Progressive runtime optimizations
Higher class cache hit rate
More effective task I/O caching

7. "Discovered the beauty of the
@gradle daemon, and now reaping the
benefits of sub-second builds"
@tylerjharden

8. "Enabling the #gradle daemon took
my build from 13s to 1.1s. This should
be the default."
@GDBolinger

9. 5th build typically
30-90% faster

10. Smokin'
fast!

11. Daemon in Gradle 3.0

12. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

13. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

14. --daemon
org.gradle.daemon=true

15. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

16. Resource Awareness
System Memory
Daemon JVM Memory
GC Activity
Other Daemons

17. What we've built is a
framework for making the
Daemon more intelligent

18. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

19. GRADLE-3018*
GRADLE-3481*
GRADLE-2803
GRADLE-3265
GRADLE-3315
GRADLE-2828
GRADLE-2275*
GRADLE-2415
GRADLE-2629
GRADLE-2367
GRADLE-2273
GRADLE-2271
Reasons not to use the Daemon
* In Progress

20. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

21. Better UX

22. Daemon in Gradle 3.0
Enabled by default
Resource-aware
More robust, especially on Windows
Better UX
Integrated with Gradle Build Scans

23. Gradle Build Scans

24. Everyday Daemon Use

25. When should I use the Daemon?
All projects, everywhere
except possibly CI

26. Daemon in IDEs
All IDEs always use the Daemon
through the Gradle Tooling API

27. Reusing Daemons across projects
Same Gradle version
Same $JAVA_HOME
Compatible JVM Args

28. How do I score one of those sweet,
rare Gradlephant transfer stickers?
Bribery

29. Maximizing
Performance

30. Effective Daemon Reuse
gradle --status
gradle --info shows Daemon stopped reasons
org.gradle.daemon.idletimeout

31. Daemon Performance Logging
org.gradle.daemon.performance.logging=true
~/.gradle/daemon/$VERSION/daemon-$PID.out.log

32. Daemon Performance Tuning
org.gradle.daemon.
performance.tenured-usage-expire-at=90
org.gradle.daemon.
performance.tenured-rate-expire-at=1.2
org.gradle.daemon.
performance.permgen-usage-expire-at=80
~/.gradle/daemon/$VERSION/daemon-$PID.out.log

33. Build slow, even with Daemon?
Gradle Build Scans to the rescue

34. gradle.github.io/performance-guide
Gradle Performance Guide

35. None of these?

36. News Flash: You're at the freakin' Gradle Summit
Tweet @gradle
discuss.gradle.org
None of these?

37. Maximizing Performance
Reuse Daemon as much as possible
Use Build Scans
Gradle Performance Guide
discuss.gradle.org

38. Beyond Gradle 3.0

39. Beyond Gradle 3.0
Cross-version Daemon Registry
More intelligent caching
Better cache eviction for longer-running
Daemons

40. Beyond Gradle 3.0
Warms itself up while idle
Automatically adjusts for user behavior
through machine learning
Speculative dependency resolution and
execution

41. The Daemon is the vehicle
through which Gradle can
become proactive

42. two more things...

43. Try it today
gradle wrapper
--gradle-version 3.0-milestone-2

44. Give feedback
discuss.gradle.org

45. gradle.org/jobs
Have ideas?

46. @eriwen
Thank You
@mbarnath@ghhale @lhotari
Eric Wendelin and the Daemon Team

47. Learn more at www.gradle.org