Speed Up Your Gradle Builds with the New Gradle Critical Path Analyzer

In the world of software development, efficiency is key. Every second saved in building and testing can significantly enhance productivity, especially when scaled across multiple projects or within large teams. For developers utilizing Gradle, a common pain point has been the sometimes mysterious and prolonged duration of Gradle commands. You're not alone if you've ever wondered why your Gradle build or test is taking longer than expected. The good news is, with the introduction of the Gradle Critical Path Analyzer and Diagnostic Builds features, there's now a way to identify these bottlenecks and speed up your Gradle  builds and tests.

Identifying the Bottleneck with Critical Path

In the context of Gradle, the critical path refers to the longest chain of dependent tasks executed during a Gradle command invocation. These tasks are interdependent; if one task needs to be re-executed, all dependent tasks will also need to be re-executed, potentially leading to cache misses. This chain of dependent and executed tasks (especially the first executed one) holds the key to understanding why your build or test is taking longer than anticipated.

Gradle task graph. The critical path is marked with red.

How the Gradle Critical Path Analyzer Helps

The Gradle Critical Path Analyzer allows you to see exactly which tasks form this critical path and how long each task takes to execute. By identifying these tasks, you can begin to understand what's causing the delay in your build or test process. More importantly, by optimizing the critical path—ensuring that more tasks can be served from the build cache—you can significantly reduce the overall time your Gradle command takes to run.

Gradle Critical Path listed on a Gradle command’s Invocation Details page on Bitrise.

Diagnostic Builds: Understanding the 'Why'

Knowing which tasks are slowing you down is one thing, but understanding why those tasks are being executed in the first place is another. This is where Diagnostic Builds come into play. This feature helps you set up Gradle to receive insights into why specific tasks on the critical path were executed, allowing you to tweak your build configuration accordingly. For instance, if a task was executed because of a change in an input property, you can try optimizing your build process by eliminating the input change or pushing the change in that particular input to a later stage.

Optimizing tasks on the critical path directly contributes to the overall performance of your build.

Real-World Impact

To illustrate the potential impact of these features, consider an example of the open source Gradle project, Amaze File Manager. Using Diagnostic Builds, we discovered that the :app:testPlayDebugUnitTest task was being executed due to a change in the version code. By moving the version code modification to a later stage, as it was unnecessary for unit tests and linting, we reduced the duration of the Android Unit Test step from 23 minutes to just 40 seconds.

A specific task’s details on the Invocation Details page.

You can check the results here:

Learn More and Get Started

Eager to dive in and start optimizing your Gradle builds? For a deeper understanding of Gradle Diagnostic Builds, check out Bitrise's DevCenter.

Not yet a Bitrise Build Cache user? No problem. You can begin your journey to more efficient builds with a 30-day, no-strings-attached free trial at Bitrise.

Conclusion

Tools like the Gradle Critical Path Analyzer and Diagnostic Builds are invaluable in the quest for efficiency and speed in our engineering practices. They provide clarity on what's slowing down our builds and empower us to make informed decisions to optimize our processes. So, why wait? Start exploring these features today and take a significant step towards more efficient, faster builds.

Stay curious, stay efficient, and keep building amazing things!

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