Learn how Microsoft evolved it’s build caching algorithm with BuildXL to support large-scale distributed builds.
Overview
The article discusses the evolution of Microsoft Build Accelerator (BuildXL) and its role in enabling large-scale distributed builds for Microsoft's extensive codebases. It highlights the challenges of traditional build systems and how BuildXL improves reliability and efficiency through advanced caching techniques and runtime monitoring.
What You'll Learn
1
How to implement reliable distributed builds using Microsoft Build Accelerator
2
Why caching is crucial for incremental builds in large codebases
3
When to apply runtime file access monitoring for build reliability
Prerequisites & Requirements
- Understanding of distributed computing concepts
- Familiarity with build systems and caching mechanisms(optional)
Key Questions Answered
How does BuildXL improve the reliability of distributed builds?
BuildXL enhances reliability by utilizing runtime file access monitoring to ensure that only the correct files are read during builds. This prevents discrepancies that can lead to incorrect incremental builds, thereby increasing trust in the build results.
What is the two-phase cache lookup in BuildXL?
The two-phase cache lookup allows for a static set of inputs to be processed initially, followed by a dynamic discovery of inputs at build time. This ensures all consumed inputs are included in the cache fingerprint, maintaining correctness without requiring burdensome specifications from developers.
What challenges does BuildXL address in large C++ codebases?
BuildXL addresses challenges related to header directories in large C++ codebases by allowing dynamic discovery of inputs during builds. This approach mitigates the issues of maintaining precise annotations or over-approximating inputs, which can negatively impact cache hit rates.
Key Statistics & Figures
Reduction in build time
From over 24 hours to minutes
This significant improvement demonstrates the efficiency of BuildXL and CloudBuild in handling large codebases.
Technologies & Tools
Build Tool
Microsoft Build Accelerator
Used for distributed builds and caching in large codebases.
Build Infrastructure
Cloudbuild
Provides the underlying infrastructure for distributed builds.
Key Actionable Insights
1Implementing BuildXL can drastically reduce build times from over 24 hours to just minutes.This is particularly beneficial for teams working with large codebases, as it allows for faster iterations and more efficient development cycles.
2Utilizing runtime file access monitoring can enhance build reliability and trust in incremental builds.By ensuring that only necessary files are accessed, teams can avoid issues related to stale or incorrect build outputs, leading to higher quality software.
3Adopting a two-phase cache lookup can simplify dependency management in complex projects.This approach reduces the burden on developers to maintain precise input specifications, allowing for more focus on coding rather than build configuration.
Common Pitfalls
1
Failing to trust incremental builds can lead to unnecessary clean builds.
This often happens due to past discrepancies in build systems, but with BuildXL's reliable caching, teams can confidently utilize incremental builds to save time.
Related Concepts
Distributed Computing
Caching Mechanisms
Incremental Builds
Build System Reliability