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diff --git a/docs/performance/reporting_a_performance_problem.md b/docs/performance/reporting_a_performance_problem.md new file mode 100644 index 0000000000..efe4f09f9c --- /dev/null +++ b/docs/performance/reporting_a_performance_problem.md @@ -0,0 +1,94 @@ +# Reporting a Performance Problem + +This article will guide you in reporting a performance problem using the +built-in Gecko Profiler tool. + +## Enabling the Profiler toolbar button + +These steps only work in Firefox 75+. + +1. Visit [https://profiler.firefox.com/](https://profiler.firefox.com/) +2. Click on *Enable Profiler Menu Button* +3. The profiler toolbar button will show up in the top right of the URL + bar as a small stopwatch icon. + + + +4. You can right-click on the button and remove it from the toolbar + when you're done with it. + +## Using the Profiler + +When enabled, the profiler toolbar button is not recording by default. +Recording can be done by clicking on the toolbar icon to open its panel. +Make sure to choose an appropriate setting for the recording (if you're +not sure, choose Firefox Platform), and then choosing **Start +Recording**. The toolbar icon turns blue when it is recording. + +The profiler uses a fixed size buffer to store sample data. When it runs +out of space in its buffer, it discards old entries so you may want to +increase the buffer size if you find you are unable to capture the +profile quickly enough after you notice a performance problem. If you +choose Custom Settings (and then clicking Edit Settings) for the +profiler, you can adjust the size of the buffer (presently defaults to +90 MB) and the time interval between data collection (presently defaults +to 1 ms). Note that increasing the buffer size uses more memory and can +make capturing a profile take longer. + + + +Using the keyboard shortcuts is often more convenient than using the +mouse to interact with the UI: + +* Ctrl+Shift+1 - Start/Stop the profiler +* Ctrl+Shift+2 - Take a profile and launch the viewer to view it + +## Capturing and sharing a profile + +1. While the profiler is recording, reproduce the performance problem. + If possible let the problem manifest itself for 5-10 seconds. +2. Press **Ctrl+Shift+2** or click on the profiler toolbar icon in the + top right and select **Capture**. Try to do this within a few + seconds from reproducing the performance problem as only the last + few seconds are recorded. If the timeline has a large red block + it's a good sign.  +3. The data will open in a new tab. Wait until the \"Symbolicating call + stacks\" notification disappears before sharing the profile. +4. There will be a button in the top right labeled **Upload Local Profile** which + will allow you to upload this profile and once completed will write + out a link. Before uploading, the Upload button asks you what data + you'd like to publish to our servers. +5. Note that while it's possible to strip profiles of potentially + privacy sensitive information, the less information a profile + contains, *the harder it is to analyze and turn into actionable + data.* +6. Once uploaded, copy permalink URL to your clipboard by right + clicking and [add the profile URL to a bug](https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=Performance) + for your performance problem and/or send it to the appropriate + person. Try to give some context about what you were doing when the + performance problem arose such as the URL you were viewing and what + actions were you doing (ex. scrolling on gmail.com). + + + +## Viewing addon performance in GeckoView + +Sometimes an addon or more are slowing down Firefox. These addons might +be using the extension API in ways that were not meant to. You can see +which of these addons are causing problems by adding the +**moz-extension** filter. + + + +Make sure you are selecting the process that is using up the CPU since +all of the processes are shown. You might have a content process using +up the CPU and not the main one. + +Make sure you are doing whatever it is that slows down Firefox while +recording the profile. For example you might have one addon that slows down page load +and another one that slows down tab switch. + +Your first reflex once you find what addon is slowing down the profile +might be to disable it and search for alternatives. Before you do this, +please share the performance profile with the addon authors through a +bug report. Gecko profiler allows you to share a link with the profile. |