Gecko Profiler

This add-on lets you collect profiles from Firefox, and open those profiles in perf-html.

Installation

The easiest way to install it is to go to https://perf-html.io/ and click the link on there.

Doing so will install the file gecko_profiler.xpi from this repository.

Usage

The add-on adds a toolbar button to your main toolbar. The button's icon is blue if the profiler is running and gray if the profiler is stopped. To start the profiler, click the toolbar button, and in the panel that opens, click "Start" in the top right corner.

Profile data is stored in a circular buffer. As soon as the buffer fills up for the first time, old data is discarded as new data is added. That means that you can leave the profiler running, and collect a snapshot of the most recent couple of seconds at any time.

You can control the profiler with two keyboard shortcuts:

• Ctrl+Shift+1: Stop / Restart profiling
• Ctrl+Shift+2: Capture the profile. This captures the current contents of the profiler buffer, opens a tab with perf-html at https://perf-html.io/, and sends the profile to it.

If you want to run your own perf-html instance or want profiles to be sent to a different site that you're developing, you can change the “Reporter URL” preference of this add-on on about:addons.

Development

Make sure you have somewhat recent versions of node and npm installed. Then:

$ git clone https://github.com/devtools-html/Gecko-Profiler-Addon/
$ cd Gecko-Profiler-Addon/
$ npm install
$ npm start

The npm start command runs Firefox Nightly by default. To run other releases of Firefox use the following npm start commands.

Beta Firefox

npm start --geckoprofiler:firefox=beta

Release Firefox

npm start --geckoprofiler:firefox=firefox

Release config

Or you can set the local config to keep the default for the life of your local repository and no longer need to pass the config on the command line.

npm config set geckoprofiler:firefox beta
npm start

Packaging a new version

If you want to package a new version of the add-on, you need to be registered as an author of the add-on on addons.mozilla.org. Otherwise you can ignore this section and ask @mstange or @gregtatum to do the packaging for you.

If you are registered as an author of the add-on on addons.mozilla.org, you should use your API key and API secret.

Packaging a new version works like this:

1. Commit your other changes first, so that the update can be its own changeset.
2. Go to manifest.json and increment the version.
3. Go to updates.json and do the same (the two need to match).
4. Set your environment variables $AMO_JWT_ISSUER and $AMO_JWT_SECRET to the API key an API secret respectively.
5. Run `npm run sign-extension'
6. Commit the changes to manifest.json, updates.json and gecko_profiler.xpi with the commit message Release <new version number>..
7. Create a PR and merge.

Landing these changes in the https://github.com/devtools-html/Gecko-Profiler-Addon/ repository will automatically cause existing installations of the add-on to update to the new version. This works because we specify the following URL as the update_url in manifest.json: https://raw.githubusercontent.com/devtools-html/Gecko-Profiler-Addon/master/updates.json. And that file contains the following "update link" URL: https://raw.githubusercontent.com/devtools-html/Gecko-Profiler-Addon/master/gecko_profiler.xpi This URL always points at the most recent gecko_profiler.xpi in the repository.

Known issues

• Does not support getting profiles from Firefox for Android.