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flutter / third_party / perfetto / 21160e8c41471a982b5567089a8ab57e3bcb5fa7
commit21160e8c41471a982b5567089a8ab57e3bcb5fa7[log] [tgz]
authorLalit Maganti <lalitm@google.com>Tue Oct 16 09:40:29 2018 +0100
committerLalit Maganti <lalitm@google.com>Tue Oct 16 09:40:29 2018 +0100
tree9edd3b0bc999a7677d8e1fd16c2bf1c18fcfd6de
parent44bf361719b3c1c7c36e4f708097f847cea6ab9c [diff]
trace_processor: add diff testing for trace processor

Trace processor is notoriously hard to test using unit or integration
tests because of the intermediate steps being closely tied to the code
and being implementation dependent.

Fundamentally, all we really care about is that for a certain set of
traces and queries, we maintain correctness and performance.

This can be done using diff testing where we take a trace and a query
and run the whole end-to-end trace processor over it, comparing the
output to the expected (i.e. correct) output and complaining if that is
not correct.

This CL only addresses the correctness portion. The performance portion
will be tackled in a follow-up.

Bug: 117596113
Change-Id: Idbfe1fc732bea9b3b7a926ef2d99d3c2ac90dc16
5 files changed
tree: 9edd3b0bc999a7677d8e1fd16c2bf1c18fcfd6de
  1. build_overrides/
  2. buildtools/
  3. debian/
  4. docs/
  5. gn/
  6. include/
  7. infra/
  8. protos/
  9. src/
  10. test/
  11. tools/
  12. ui/
  13. .clang-format
  14. .gitignore
  15. .gn
  16. .travis.yml
  17. Android.bp
  18. Android.bp.extras
  19. BUILD.gn
  20. codereview.settings
  21. MODULE_LICENSE_APACHE2
  22. NOTICE
  23. OWNERS
  24. perfetto.rc
  25. PRESUBMIT.py
  26. README.chromium
  27. 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

Bugs

  • For bugs affecting Android or the tracing internals use the internal bug tracker (go/perfetto-bugs).
  • For bugs affecting Chrome use http://crbug.com, Component:Speed>Tracing label:Perfetto.