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fuchsia/third_party/github.com/google/perfetto/471b491d2aff210a6d195b292eefe1a89eb32ba2
commit
471b491d2aff210a6d195b292eefe1a89eb32ba2
[log]
author
Steve Golton <stevegolton@google.com>
Tue Jan 20 12:00:15 2026 +0000
committer
GitHub <noreply@github.com>
Tue Jan 20 12:00:15 2026 +0000
tree
8bb6c008abc3e05d1c376c8ab3974d5f2070acbe
parent
d2248747cdbefc9f8f11faa5f01819570feaf593 [diff]
ui: Fix sticky header rendering issues when using virtual track scrolling (#4482)

Currently, when using virtual scrolling, when the original position of a
group track scrolls out of view, it gets rendered in 'lite' mode, which
removes buttons and other DOM elements and just leaves the title text.

The issue is because summary track headers stick to the top of the
viewport using `position: sticky`, they still appear on screen despite
their original position being offscreen. Thus, we need to detect this
and find render them in full mode if they are visible at all.

This patch keeps track of whether ANY children of a group are on screen
and renders the parent track in full mode if so.

Before:
<img width="278" height="143" alt="image"
src="https://github.com/user-attachments/assets/ff902013-83af-421a-9efb-36e03104bdf6"
/>

After:
<img width="272" height="174" alt="image"
src="https://github.com/user-attachments/assets/2d15a9c6-3a38-4eb0-bc26-b5f424164c19"
/>
1 file changed
tree: 8bb6c008abc3e05d1c376c8ab3974d5f2070acbe
  1. .github/
  2. bazel/
  3. build_overrides/
  4. buildtools/
  5. contrib/
  6. docs/
  7. examples/
  8. gn/
  9. include/
  10. infra/
  11. protos/
  12. python/
  13. src/
  14. test/
  15. third_party/
  16. tools/
  17. ui/
  18. CLAUDE.md ⇨ docs/AGENTS.md
  19. GEMINI.md ⇨ docs/AGENTS.md
  20. .bazelignore
  21. .bazelrc
  22. .bazelversion
  23. .clang-format
  24. .clang-tidy
  25. .git-blame-ignore-revs
  26. .gitallowed
  27. .gitattributes
  28. .gitignore
  29. .gn
  30. .style.yapf
  31. Android.bp
  32. Android.bp.extras
  33. BUILD
  34. BUILD.extras
  35. BUILD.gn
  36. CHANGELOG
  37. CONTRIBUTORS.txt
  38. DIR_METADATA
  39. heapprofd.rc
  40. LICENSE
  41. meson.build
  42. METADATA
  43. MODULE.bazel
  44. MODULE.bazel.lock
  45. MODULE_LICENSE_APACHE2
  46. OWNERS
  47. OWNERS.github
  48. perfetto.rc
  49. perfetto_flags.aconfig
  50. PerfettoIntegrationTests.xml
  51. persistent_cfg.pbtxt
  52. README.chromium
  53. README.md
  54. TEST_MAPPING
  55. traced_perf.rc
  56. WORKSPACE
README.md

Perfetto - System profiling, app tracing and trace analysis

Perfetto is an open-source suite of SDKs, daemons and tools which use tracing to help developers understand the behaviour of complex systems and root-cause functional and performance issues on client and embedded systems.

It is a production-grade tool that is the default tracing system for the Android operating system and the Chromium browser.

Core Components

Perfetto is not a single tool, but a collection of components that work together:

  • High-performance tracing daemons: For capturing tracing information from many processes on a single machine into a unified trace file.
  • Low-overhead tracing SDK: A C++17 library for direct userspace-to-userspace tracing of timings and state changes in your application.
  • Extensive OS-level probes: For capturing system-wide context on Android and Linux (e.g. scheduling states, CPU frequencies, memory profiling, callstack sampling).
  • Browser-based UI: A powerful, fully local UI for visualizing and exploring large, multi-GB traces on a timeline. It works in all major browsers, requires no installation, and can open traces from other tools.
  • SQL-based analysis library: A powerful engine that allows you to programmatically query traces using SQL to automate analysis and extract custom metrics.

Why Use Perfetto?

Perfetto was designed to be a versatile and powerful tracing system for a wide range of use cases.

  • For Android App & Platform Developers: Debug and root-cause functional and performance issues like slow startups, dropped frames (jank), animation glitches, low memory kills, and ANRs. Profile both Java/Kotlin and native C++ memory usage with heap dumps and profiles.
  • For C/C++ Developers (Linux, macOS, Windows): Use the Tracing SDK to instrument your application with custom trace points to understand its execution flow, find performance bottlenecks, and debug complex behavior. On Linux, you can also perform detailed CPU and native heap profiling.
  • For Linux Kernel & System Developers: Get deep insights into kernel behavior. Perfetto acts as an efficient userspace daemon for ftrace, allowing you to visualize scheduling, syscalls, interrupts, and custom kernel tracepoints on a timeline.
  • For Chromium Developers: Perfetto is the tracing backend for chrome://tracing. Use it to debug and root-cause issues in the browser, V8, and Blink.
  • For Performance Engineers & SREs: Analyze and visualize a wide range of profiling and tracing formats, not just Perfetto's. Use the powerful SQL interface to programmatically analyze traces from tools like Linux perf, macOS Instruments, Chrome JSON traces, and more.

Getting Started

We‘ve designed our documentation to guide you to the right information as quickly as possible, whether you’re a newcomer to performance analysis or an experienced developer.

  1. New to tracing? If you're unfamiliar with concepts like tracing and profiling, start here:

  2. Ready to dive in? Our “Getting Started” guide is the main entry point for all users. It will help you find the right tutorials and documentation for your specific needs:

  3. Want the full overview? For a comprehensive look at what Perfetto is, why it's useful, and who uses it, see our main documentation page:

Debian Distribution

For users interested in the Debian distribution of Perfetto, the official source of truth and packaging efforts are maintained at Debian Perfetto Salsa Repository

Community & Support

Have questions? Need help?

We follow Google's Open Source Community Guidelines.