Description
The Uploads and Downloads tabs in invocation details now include cache performance histograms and throughput metrics to help you better understand how cache transfer performance affects your builds.
Highlights:
- Latency and size histograms: You can now view histogram distributions for both cache latency and blob size, shown separately for uploads and downloads.
- Throughput metrics per build: Invocation details now also show P50 and P10 throughput for that build.
- Small blobs excluded from throughput calculation: Blobs smaller than 16 KB are excluded from throughput metrics, because those transfers tend to reflect network latency rather than meaningful throughput. They are still included in the latency histogram and individual blob list.
- Helps investigate cache performance impact: These views make it easier to understand whether cache transfer speed is affecting your build, or to rule it out quickly.
- Available across multiple invocation types: Supported for Gradle, Xcode, and ccache invocations.
- Available from Build Cache CLI v3.9.0: These metrics are collected and displayed for invocations using Build Cache CLI 3.9.0 or newer.
Why This Matters
When investigating build performance, cache transfer speed is often suspected as a bottleneck. In practice, many cache blobs are served very quickly, often under 16 ms. These new visualizations help teams validate that assumption with real build data and focus optimization efforts where they matter most.
Bottom line: Invocation details now give you a clearer view of Build Cache transfer performance, making it easier to diagnose latency issues, or confidently rule cache I/O out as the cause of slow builds.