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gerrit-public.fairphone.software / platform / external / perfetto / 674076d06d114f969b8d87a9acf7d7e61a5dc4e3
commit674076d06d114f969b8d87a9acf7d7e61a5dc4e3[log] [tgz]
authorPrimiano Tucci <primiano@google.com>Mon Oct 01 10:41:09 2018 +0100
committerPrimiano Tucci <primiano@google.com>Mon Oct 01 10:41:09 2018 +0100
tree5172c02b7957c07ef22971eab1ce5b03e4dbd44b
parent5cfa93810a407da48fe72b9e11df6e2bb7f17d9b [diff]
Introduce support for deferred start (fast triggering)

This CL introduces new Setup methods to both the
producer and consumer API. The API changes are designed
to be backwards compatible with the prior versions of
Android.

From the producer viewpoint: each data source now sees a
SetupDataSource() method before the StartDataSource() method.
The data source instance id and config is identical. This
gives the data source a chance to setup itself before actually
starting.

From the consumer viewpoint:
A new "deferred_start" field is added to the TraceConfig.
When deferred_start is true, the EnableTracing method
brings up all the tracing harness and calls the
SetupDataSource() methods on the producers, but doesn't
start them. Data sources are started only when calling
StartDataSource().

Note that in this CL, the ftrace data source doesn't
deal yet with the split Setup/Start phases and starts
directly upon creation. This will be fixed in a separate
CL.

Bug: 116547201
Change-Id: I2ab22c7f8ee2388f8158df733dddeef9dc9c0143
39 files changed
tree: 5172c02b7957c07ef22971eab1ce5b03e4dbd44b
  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.