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review.blissroms.org / platform_external_perfetto / 361f1e2e39054b2002ce0b22b7c74387559610a8
commit361f1e2e39054b2002ce0b22b7c74387559610a8[log] [tgz]
authorPrimiano Tucci <primiano@google.com>Tue May 08 14:13:00 2018 +0100
committerPrimiano Tucci <primiano@google.com>Tue May 08 14:15:37 2018 +0100
treebf4ed55c810e67e9a47eaa1400c0664045cf8e52
parent28894baecffa4c85a2802b558fe24430fee11e9a [diff]
Limit concurrent traces to 5 to prevent stalls in traced_probes

This re-sets a heuristic limit that has been dropped during
a previous refactoring. This is still not the right clean fix
(that would require revisiting the logic in traced_probes),
but is good enough to avoid hitting the problem in practice.

(cherry picked from commit a690a7d79fe15b1e084825a3d3e8b108750e34db)
Bug: 73052144
Change-Id: Iefec4ba044e32906092b1ceeb8e645e1f3c4c41f
Merged-In: Iefec4ba044e32906092b1ceeb8e645e1f3c4c41f
1 file changed
tree: bf4ed55c810e67e9a47eaa1400c0664045cf8e52
  1. build_overrides/
  2. buildtools/
  3. debian/
  4. docs/
  5. gn/
  6. include/
  7. infra/
  8. protos/
  9. src/
  10. test/
  11. tools/
  12. .clang-format
  13. .gitignore
  14. .gn
  15. .travis.yml
  16. Android.bp
  17. Android.bp.extras
  18. BUILD.gn
  19. codereview.settings
  20. MODULE_LICENSE_APACHE2
  21. NOTICE
  22. OWNERS
  23. perfetto.rc
  24. PRESUBMIT.py
  25. README.chromium
  26. README.md
README.md

Perfetto - Performance instrumentation and tracing

Perfetto is an open-source project for performance instrumentation and tracing of Linux/Android/Chrome platforms and user-space apps.
It consists of:

A portable, high efficiency, user-space tracing library
designed for tracing of multi-process systems, based on zero-alloc zero-copy zero-syscall (on fast-paths) writing of protobufs over shared memory.

OS-wide Linux/Android probes for platform debugging

  • Kernel tracing: a daemon that converts Kernel Ftrace events into API-stable protobufs, on device, with low overhead.
  • I/O tracing
  • Many new probes coming soon: heap profiling, perf sampling, syscall tracing.

Web-based frontend
A UI for inspection and analysis of traces (coming soon).

Batch processing of traces
A python / C++ (TBD) library for trace-based metrics (coming soon).

Perfetto Stack

Goals

Perfetto is building the next-gen unified tracing ecosystem for:

  • Android platform tracing (Systrace)
  • Chrome platform tracing (chrome://tracing)
  • App-defined user-space tracing (including support for non-Android apps).

The goal is to create an open, portable and developer friendly tracing ecosystem for app and platform performance debugging.

Key features

Designed for production
Perfetto's tracing library and daemons are designed for use in production. Privilege isolation is a key design goal:

  • The interface for writing trace events are decoupled from the interface for read-back and control and can be subjected to different ACLs.
  • Despite being based on shared memory, Perfetto is designed to prevent cross-talk between data sources, even in case of arbitrary code execution (memory is shared point-to-point, memory is never shared between processes).
  • Perfetto daemons are designed following to the principle of least privilege, in order to allow strong sandboxing (via SELinux on Android).

See docs/security-model.md for more details.

Long traces
Pefetto aims at supporting hours-long / O(100GB) traces, both in terms of recording backend and UI frontend.

Interoperability
Perfetto traces (output) and configuration (input) consists of protobuf messages, in order to allow interoperability with several languages.

See docs/trace-format.md for more details.

Composability
As Perfetto is designed both for OS-level tracing and app-level tracing, its design allows to compose several instances of the Perfetto tracing library, allowing to nest multiple layers of tracing and drive then with the same frontend. This allows powerful blending of app-specific and OS-wide trace events. See docs/multi-layer-tracing.md for more details.

Portability
The only dependencies of Perfetto's tracing libraries are C++11 and Protobuf lite (plus google-test, google-benchmark, libprotobuf-full for testing).

Extensibility
Perfetto allows third parties to defined their own protobufs for:

Allowing apps to define their own strongly-typed input and output schema. See docs/trace-format.md for more details.

Docs