Perfetto

The $dir_pw_third_party/perfetto/ module provides the perfetto protos. Only the protos are provided, and not the entire distribution, as there is no need for it.

Code synchronization

Unlike other third party libraries used by Pigweed, some perfetto source code is included in tree. A few factors drove this decision:

• Core Pigweed tracing depend on these perfetto protos. Including the protos in-tree avoids having Pigweed require an external repository.

• The perfetto repository is too large to require downstream projects to clone.

• It provides a consistent approach between between bazel and GN builds.

• Perfetto is used as part of the default build. pw package doesn’t currently have a good way to automatically install a required package.

Files are synced from perfetto repository to the third_party/perfetto/repo directory in Pigweed. The files maintain their original paths under that directory.

Process

Code is synchronized between the perfetto repository and the Pigweed repository using the third_party/perfetto/copy.bara.sky Copybara script.

To synchronize with the pigweed repository, run the copybara tool with the script:

copybara third_party/perfetto/copy.bara.sky

That creates a Gerrit change with updates from the perfetto repo, if any.

If the copybara command fails, the Copybara script may need to be updated. Try the following:

• Ensure that the source files in copy.bara.sky are up-to-date. Fix the list if any files were renamed in Fuchsia.