> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/continuous-integration/use-harness-ci/use-harness-ci/harness-ci-intelligence.md).
# Harness CI Intelligence
Harness CI Intelligence leverages a suite of CI features to optimize your builds.
Harness Continuous Integration (CI) Intelligence features are designed to smartly speed up builds and boost efficiency.
### Build Intelligence
[Build Intelligence](/continuous-integration/use-harness-ci/use-harness-ci/build-and-upload-artifacts/build-intelligence.md) is part of the suite of intelligent features in Harness CI designed to improve build times. It saves time by reusing outputs from previous builds. Build Intelligence works by storing these outputs locally or remotely and retrieving them when inputs haven't changed. This process avoids the need to regenerate outputs, significantly speeding up the build process and enhancing efficiency.
Build Intelligence in Harness CI is currently available for **Gradle**, **Bazel**, and **Maven** (version 3.9+).
### Test Intelligence
Testing is an important part of Continuous Integration. Testing safeguards the quality of your product before shipping. However, test cycles often involve many tests, and it can take a significant amount of time for the tests to run. Additionally, the tests that run might be irrelevant to the code changes that triggered the build.
Harness Test Intelligence (TI) helps your test cycle move faster without compromising quality. Harness TI speeds up builds by running only the unit tests that matter for the specific code changes made, instead of executing the entire test suite every time. It automatically identifies and selects the relevant tests, skipping the rest. You can also configure TI to split tests across multiple jobs and run them in parallel, further reducing test time.
Test Intelligence gives you full visibility into which tests were selected and why. This can help you identify negative trends and gain insights to improve test quality and coverage. Using TI doesn't require you to change your build and test processes.
To learn more about the Test Intelligence architecture, how it works, and how to enable it, go to [Test Intelligence overview](/continuous-integration/use-harness-ci/use-harness-ci/run-tests/ti-overview.md).
While Test Intelligence is only for unit tests, you can [run a variety of tests in your CI pipelines](/continuous-integration/use-harness-ci/use-harness-ci/run-tests/run-tests-in-ci.md).
Example: Time and cost savings with Test Intelligence
We ran Test Intelligence on our biggest repository, Harness-Core. Here's what we achieved:
* PRs checked: 3000
* Average UT time without TI: 75 minutes
* Average UT time with TI: 25 minutes
Here's how Harness Test Intelligence performed with some popular open-source repositories:
| **Project name** | **Average test run time without TI** | **Average test run time with TI** |
| -------------------- | ------------------------------------ | --------------------------------- |
| Harness-Core | 75 mins | 25 mins |
| Incubator Pinot | 338 mins | 228 mins |
| Hudi | 58 mins | 43 mins |
| RocketMQ | 4.6 mins | 3.1 mins |
| Spring Cloud Alibaba | 0.744 mins | 0.59 mins |
| Incubator Shenyu | 1.16 min | 0.4 min |
| Sentinel | 1.90 min | 1 min |
### Cache Intelligence
Modern continuous integration systems execute pipelines inside ephemeral environments that are provisioned solely for pipeline execution and are not reused from prior pipeline runs. As builds often require downloading and installing many library and software dependencies, caching these dependencies for quick retrieval at runtime can save a significant amount of time.
With [Cache Intelligence](/continuous-integration/use-harness-ci/use-harness-ci/caching-ci-data/cache-intelligence.md), Harness automatically caches and restores software dependencies to speed up your builds - hassle free.
You can use Cache Intelligence with any [build infrastructure](/continuous-integration/use-harness-ci/use-harness-ci/set-up-build-infrastructure/which-build-infrastructure-is-right-for-me.md).
When you use Cache Intelligence with Harness CI Cloud, the cache is stored in the Harness-managed environment. When running builds in self-managed infrastructures, [configure default object storage (Azure Blob Storage, GCP Cloud Storage, AWS S3, or any S3-compatible storage)](/harness-ai/use-harness-platform/settings/default-settings.md#continuous-integration) that Harness can use to seamlessly store and manage the cache.
### Docker Layer Caching (DLC)
In modern CI systems, Docker images are frequently built in ephemeral environments, created solely for pipeline execution.
With [Docker Layer Caching (DLC)](/continuous-integration/use-harness-ci/use-harness-ci/caching-ci-data/docker-layer-caching.md), Harness seamlessly caches Docker image layers between builds to significantly accelerate the time it takes to build Docker images.
You can use DLC with any [build infrastructure](/continuous-integration/use-harness-ci/use-harness-ci/set-up-build-infrastructure/which-build-infrastructure-is-right-for-me.md).
When you use DLC with Harness CI Cloud, the cache is stored in the Harness-managed environment. When running builds in self-managed infrastructures, [configure default object storage (Azure Blob Storage, GCP Cloud Storage, AWS S3, or any S3-compatible storage)](/harness-ai/use-harness-platform/settings/default-settings.md#continuous-integration) that Harness can use to seamlessly store and manage the cache.
### Comparing Cache Intelligence, Docker Layer Caching, and Build Intelligence
| Feature | Description | Purpose | Context | Additional Details |
| ------------------------------ | ---------------------------------------------------------------------------------------------------------- | ------------------------------------------------------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Docker Layer Caching (DLC)** | Reuses previously built Docker image layers, building only what’s necessary. | Speeds up Docker image build and push steps | Docker images | Can be used with any build infrastructure; cache stored in Harness cloud environment or object storage (Azure Blob Storage, GCP Cloud Storage, AWS S3, or any S3-compatible storage). |
| **Cache Intelligence** | Caches software dependencies (e.g., plugins) downloaded at the start of the build in a specific directory. | Caches dependencies to save download time | Software dependencies | Automatically caches and restores dependencies; works with any build infrastructure; stored in Harness cloud or object storage (Azure Blob Storage, GCP Cloud Storage, AWS S3, or any S3-compatible storage). |
| **Build Intelligence** | Caches outputs of cacheable build tasks as identified by the build tool (e.g., Gradle tasks). | Speeds up overall build process by reusing task outputs | Build outputs | Available in Harness Cloud and Kubernetes infrastructure, with support for local runner and VM runner coming soon. Available for Gradle, Bazel, and Maven (version 3.9+). |
### Intelligence Savings
Harness Intelligence optimizes your build stages by reducing execution times and providing insights into where time savings are achieved. This section explains how the time savings are calculated and displayed, helping you understand the benefits of using Harness Intelligence features.
{% hint style="info" %}
This feature is available with the `CI_PARSE_SAVINGS` feature flag. Please contact [Harness Support](mailto:support@harness.io) to enable the feature.
{% endhint %}
Below is a screenshot demonstrating the time savings for a **Build** stage using Cache Intelligence and Test Intelligence.
#### How is Build stage time saving calculated
Harness calculates time savings by comparing the duration of the Build stage before and after Harness intelligence time savings are observed. When you first run your pipeline with Harness Intelligence features, a full run is executed, creating a baseline duration for the Build stage without any smart optimizations.
When Build stages are optimized with Intelligence features and savings are observed, the savings are shown compared to the baseline. A baseline can also be updated in subsequent runs where intelligence features are enabled but a full run (non-optimized) is executed. For example, depending on the code change, Test Intelligence may choose to run all tests, generating a new baseline.
{% hint style="info" %}
If a stage contains parallel steps, the reported savings will be based on the CPU time saved by each parallel step from previous non-optimized runs. However, these savings are not reflective of wall clock time. Therefore, summing the CPU time savings may not accurately represent the actual time saved in minutes. Additionally, any changes in the stage logic, such as adding or removing steps, can impact the accuracy of time savings calculations.
{% endhint %}
{% @harness-feedback/feedback %}