Performance Triage

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If you have any feedback/suggestions/questions regarding the performance triage process, you can share them in #perf-triage, or reach out to Dave Hunt or Frank Doty.

Nomination

Bugzilla

To (re)nominate a bug for triage, set the Performance Impact flag in Bugzilla to ?

This can be found by clicking Show Advanced Fields followed by Set bug flags when entering a new bug:

Bugzilla performance nomination on new bug form.png

Or by expanding the Tracking section when editing an existing bug:

Screenshot 2022-02-24 at 19.53.54.png

GitHub

To nominate a bug for triage, add the Performance label to an issue. This can be done by filing an new issue with the "Performance issue" template:

Screenshot of file a "Performance issue" template on GitHub

Or by opening an existing issue on GitHub and selecting the label from the right-hand bar:

Screenshot of adding a performance label on GitHub

Currently, only the following GitHub repositories are supported:

Queries

Performance triage

Full Query
ID Summary Status
1363383 Channel switching on Slack is slow NEW
1419502 Specific PDF page takes 10s to render (200% cpu) REOPENED
1436734 pdf with many images uses a lot of memory on scrolling NEW
1445735 Unable to render specific PDF file. NEW
1448783 Firefox launcher is blocked in slow DNS queries for local hostname NEW
1485065 Firefox Pdf single page document loads several minutes while other browsers instantly (attached sample PDF) NEW
1534745 cookies.sqlite is read on the main thread before first paint NEW
1536420 PDF uses lot of memory when decoding UNCONFIRMED
1580638 Startup default browser check causes mainthread IO on Linux NEW
1606631 Inefficient z-ordering of elements in the browser UI, causes large layers with current WebRender heuristics ASSIGNED
1625271 getNewSideloads checks for system add-ons last modified time on the main thread at the end of startup NEW
1627086 Init safe browsing later during startup NEW
1646300 Having YouTube tab open with no video playing shows high energy usage UNCONFIRMED
1651434 Tab loading takes a very long time after a new startup or a restart NEW
1674511 Reduce the amount of work we do for location hash and history push/replaceState changes in XULBrowserWindow's onLocationChange NEW
1695273 [NSFW] Slowness remaining on scrolling nsfw reddit after bug 1694017 is resolved NEW
1731514 Extreme memory surge when opening a certain pdf-file NEW
1785979 Slow rendering and opening of certain PDF types NEW
1789275 Could we startup the skeleton ui earlier? NEW
1805122 React app performance improves dramatically when page is not visible NEW
1844961 linkedin.com will crash the whole computer (El Capitain, Mac OS X 10.11.6) by using up the whole storage. The browser task (FirefoxCP Web Content) grows and grows in the GByte ranges. NEW
1846115 The debugger can cause webpage lagging UNCONFIRMED
1870209 Webpage sometimes no response in Fenix with high CPU usage UNCONFIRMED
1870405 Very slow time to first page load when opening Fenix with hundreds of tabs UNCONFIRMED
1874013 Incorrect and slow rendering of some PDF files NEW
1878133 PDF takes excessively long to render NEW
1880752 YouTube and other web-based video sites sometimes dropping frames NEW
1884394 Frequent inability to use 'back' NEW
1887129 Slow responses on trivia game in Fenix Nightly vs. Chrome on same device & network connection NEW
1888064 Firefox takes a long time to start prior to Load a Website UNCONFIRMED
1888322 Latest update crashes and cause processor loop crash. UNCONFIRMED
1888439 Memory leak on Business Insider UNCONFIRMED
1888525 helpdeskgeek site runs a lot more JS in Firefox than in Chrome (checkerboards during scrolling) NEW
1889461 Ozon.ru eats up RAM UNCONFIRMED
1889648 Fenix restarts itself soon after getting killed by the user NEW
1889722 FirefoxCP Isolated Content Using Almost 10GB RAM UNCONFIRMED
1890537 Firefox nearly froze when I zoomed in in this PDF NEW
1890599 LCP end timestamp doesn't include composition time NEW
1890699 Every time Firefox has an error, it appears to take over my OS, which is Windows 11, as the entire screen temporarily freezes up along with Mozilla, even shutting down File Explorer. UNCONFIRMED
1891411 Very high memory usage(95%) by a single website UNCONFIRMED
1891979 Very High Ram usage UNCONFIRMED
1891990 Update gemmology to match recent xsimd API changes ASSIGNED
1892231 Add flag in page load event to identify whether webdriver is being used NEW
1892367 3%-5% regression on multiple AWFY-SP2 benchmark suites around 17Apr2024 (mostly on todo-mvc-Deleting- XXXX type benchmarks) NEW

44 Total; 44 Open (100%); 0 Resolved (0%); 0 Verified (0%);


Performance triage (pending-needinfo)

Full Query
ID Summary Status
1709763 Menus show a delay of 4-5 seconds on mouse input (Wayland/WebRnender?) UNCONFIRMED
1805255 Firefox has 50% more soft page faults than Chrome running Speedometer 2 NEW
1866145 Delay opening new windows due to long GC slices in the parent process NEW
1870532 Firefox 120.0.1 grabs 100% of cpu resources and freezes UNCONFIRMED
1872368 Since the last update 121.0 Firefox uses insane amount of Ram 99% of my 32GB without any real reason and if it gets closed it buges out for 10 seconds spikes over the ram limit just to slowly close UNCONFIRMED
1872414 Firefox lags after latest update, high memory use (121.0 12-2023) UNCONFIRMED
1875547 Slow (single-threaded) PDF rendering for documents with lots of vector shapes NEW
1876708 firefox using 3.4gb of memory with a few tabs open UNCONFIRMED
1877007 extremely high CPU usage even with one tab open on the splash screen UNCONFIRMED
1879177 3 youtube tabs are using 7GB of RAM UNCONFIRMED
1879905 firefox consuming 2 GB of RAM with 8 tabs open UNCONFIRMED
1882916 Firefox consumes a lot of CPU and makes me Mac M2 hang for a good 15 seconds UNCONFIRMED
1882952 Firefox Browser Freezes when Opening Multiple Tabs UNCONFIRMED
1883246 firefox using large amount of memory UNCONFIRMED
1883475 huge amount of memory storage (constantly) idk why pls help/................................................................................................................................................. UNCONFIRMED
1883507 Memory usage is too high 23GB and up to 60% CPU usage. UNCONFIRMED
1883669 Memory Problem UNCONFIRMED
1884296 Firefox is using lots of memory when only having several tabs open UNCONFIRMED
1885796 Use to many Ram UNCONFIRMED
1891345 Enourmous RAM usage (60Gig) UNCONFIRMED
1891462 Update xsimd to new version 7eb009bca73e5cc51d05dcfcda25dfb74d6e0aaa from 2024-03-28 13:40:05 ASSIGNED

21 Total; 21 Open (100%); 0 Resolved (0%); 0 Verified (0%);


Recently opened bugs with performance keywords in the summary

Full Query
ID Summary Status
1889995 Crash in [@ java.lang.OutOfMemoryError: at java.util.ArrayList.<init>(ArrayList.java)] ASSIGNED
1890097 Perform quota checks for writable file stream in the parent process using dedicated task queues ASSIGNED
1890299 Enable Select Translations for Nightly and Early Beta NEW
1890472 sound delay with Dolby Atmos for Home Theater UNCONFIRMED
1890490 allow resizing the select translations panel NEW
1890504 Restarting or restoring two Firefox windows will no longer show the Translation button on one window if the page is already opened NEW
1890598 Menu opens differently when scrolled too fast NEW
1890622 Poor WMF hardware decoder performance after creating too many video decoders on the compositor device NEW
1890705 Middle clicking on new tab button unexpectedly performs search with clipboard contents NEW
1890763 Translations' first pop-up is not automatically displayed when the page is visited for the first time NEW
1890837 Check Translations Button Size NEW
1890838 Global Settings Entry Point For Translation Global Settings NEW
1890917 JS demo is 1.6x slower in Nightly compared to Chrome NEW
1891163 Lower performance compare with Chromium in https://demo.servo.org/experiments/dogemania/ NEW
1891170 Firefox session storage memory was lost in the old version (116.0.2/117.0) UNCONFIRMED
1891192 [Translations] The transition from reader mode to non-reader mode displays glitches on both icons NEW
1891277 JS GC memory prefs are not applied to workers ASSIGNED
1891316 VS Code release notes use a lot of CPU, even in background tabs NEW
1891335 [fission] Twitter embeds load slowly again (fission) ASSIGNED
1891593 `shader-f16` extension support in WebGPU NEW
1891655 Performance metric of getKeyRange test is not gathered NEW
1891685 Document the performance and hardware requirements for inference NEW
1891782 Eliminate Inline Event Handlers From SelectTranslationsPanel NEW
1891792 Eliminate Inline Event Handlers From FullPageTranslationsPanel NEW
1891821 Check Translations Divider Color and Adjust NEW
1891823 Check Translations Toggle State Colors NEW
1891829 Add variations of performance tests for testing using multiple databases ASSIGNED
1891878 I believe that Mozilla Firefox has memory leak issues. UNCONFIRMED
1891935 Opening a new reader mode page in a new tab from a translatable page, doesn't display the translations icon NEW
1891950 Android idle battery drain due to Firefox UNCONFIRMED
1891986 Loading font files from %windir%\Fonts via broker causes regressions on some cold performance tests. ASSIGNED
1892068 Change language from "Install" to "Download" in Translations Settings NEW
1892079 [wpt-sync] Sync PR 45764 - Don't use fast border radius with mix-blend-mode in different transform space NEW
1892083 Make MemoryNotificationDB a parent class of NotificationDB ASSIGNED
1892149 Remove or update probes expiring in Firefox 128: MEMORY_PHC_SLOTS_* NEW
1892165 Firefox 124 Performance Regression on High Intensity Video Streaming UNCONFIRMED
1892216 CSS Highlights API poor performance compared to Chrome NEW
1892272 Worker postMessage ThrottledEventQueue backpressure should be aware of outstanding structured serialization memory use in order to throttle the worker based on memory usage and not just runnable count NEW
1892359 Fix Translator Exception Handling NEW
1892383 Firefox crashes with out of memory | Crash in [@ OOM | large | webrender::renderer::Renderer::render_impl] UNCONFIRMED
1892391 PerformanceResourceTiming entries have original URLs when upgraded due to mixed content UNCONFIRMED
1892416 The translation icon is displayed on the left side of the shopping icon NEW
1892417 Survey on new tab page steals keyboard focus when user opens a new tab wanting to perform a search NEW
1892420 Translation bottom sheet is not displayed after disabling "Always translate [language]" option NEW

44 Total; 44 Open (100%); 0 Resolved (0%); 0 Verified (0%);


Triage process

Introduction

The goal of performance triage is to identify the extent to which bugs impact the performance of our products, and to move these bugs towards an actionable state. The goal is not to diagnose or fix bugs during triage. We triage bugs that have been nominated for triage and bugs in the Core::Performance component that do not have the performance impact project flag set.

During triage we may do any/all of the following:

  • Request further information from the reporter (such as a profile)
  • Set the performance impact project flag
  • Add performance keywords
  • Move the bug to a more appropriate component

Who is responsible for triage?

Everyone is welcome to take part in triage. By default, everyone on the performance team is enrolled in triage rotation, but we also have participants from outside the team.

How do I schedule a triage meeting?

If you are on triage duty, you will receive an invitation as a reminder to schedule the triage meeting on the shared performance calendar with the nominated sheriffs invited at a time that works for them. The responsibility of scheduling the meeting falls to the lead sheriff. Once a triage meeting has been scheduled, it’s a good idea to remove the reminder event from the calendar to avoid confusion. It’s a good idea to use the shared calendar, as this increases the visibility of the performance triage and allows other members of the team to contribute or observe the process.

What if a sheriff is unavailable?

The rotation script is not perfect, and doesn’t know when people are on PTO or otherwise unavailable. If the lead sheriff is available, it is their responsibility to either schedule the triage with the remaining available sheriff or to identify a suitable substitute for the unavailable sheriff(s). If the lead sheriff is unavailable, this responsibility passes onto the remaining available sheriffs.

How do I run a triage meeting?

The following describes the triage process to follow during the meeting:

  1. Ask if others would prefer you to share your screen. This can be especially helpful for those new to triage.
  2. Open the first triage query to show bugs nominated for triage or in the Core::Performance component without the performance impact project flag set. The bugs are sorted from oldest to newest. For each bug in the list, follow these steps:
    • Bugs that look like tasks that were filed by members of the Performance team will generally need to be moved to the Core::Performance Engineering component.
    • For defects: Determine if the bug is reproducible and actionable. If not, add a needinfo for the reporter asking for more information, set the performance impact project flag to pending-needinfo, and then move onto the next bug. We have a template that you can modify as needed.
    • For all bugs (including enhancements):
  3. Open the second triage query to show bugs that are waiting further information to determine the performance impact. The bugs are sorted from oldest to newest. For each bug in the list, follow these steps:
    • If the performance impact project flag was set to pending-needinfo less than 2 weeks ago, move onto the next bug.
    • If the performance impact project flag was set to pending-needinfo more than 2 weeks ago but less than 2 months ago, consider adding a needinfo for either: another reporter of the issue, someone with access to the appropriate platform(s) to attempt to reproduce the issue, or a relevant subject matter expert.
    • If the performance impact project flag was set to pending-needinfo more than 2 months ago, close the bug as inactive. You can modify the inactive bug template as needed.
  4. If time permits, open the third triage query to show recently opened bugs with performance related keywords in the summary. If any of these look like performance bugs, they can either be triaged the same way as bugs in the initial query or they can be nominated for triage in a subsequent meeting.

What if things don't go as expected?

Don't panic! The triage process is not expected to be perfect, and can improve with your feedback. Maybe the result of the triage calculator doesn't feel right, or you find a scenario that's not covered in these guidelines. In this case we recommend that you bring it up in #perf-triage, or consider scheduling a short meeting with some triage leads (you can see some recent leads in the triage rotation). If in doubt, leave a comment on the bug with your thoughts and move on. There's a chance someone will respond, but if not the next performance triage sheriffs may have some other ideas.

How do I determine the performance impact project flag?

The performance impact project flag is used to indicate a bug’s relationship to the performance of our products. It can be applied to all bugs, and not only defects. The triage calculator should be used to help determine the most appropriate value for this flag. In addition to setting the performance impact project flag, make sure to use the “Copy Bugzilla Comment” button and paste this as a comment on the bug.

If you do not have enough information to set the performance impact project flag, open a needinfo request against an appropriate individual (such as a reporter), and set the performance impact project flag to pending-needinfo.

For more information about what this flag, and it's settings mean see this blog post.

How do I determine the performance keywords?

There are several performance related keywords, which can be helpful to understand how our performance issues are distributed, or whenever there’s a concerted effort to improve a particular aspect of our products. The triage calculator may recommend keywords to set, and by typing “perf:” in the keywords field in Bugzilla, you will see the available options. Select all that apply to the bug.

How do I determine the correct Bugzilla component?

Ideally we would only have bugs in the Core::Performance component that are the responsibility of the engineers in the performance team. For performance bugs to have the best chance of being fixed, it's important to assign them to the correct component. In some cases the correct component will be obvious from the bug summary, description, or steps to reproduce. In other cases, you may need to do a bit more work to identify the component. For example, if there's a profile associated with the bug, you could see where the majority of time is being spent using the category annotations.

How do I read a performance profile?

It's useful to be able to understand a profile generated by the Firefox Profiler, and hopefully someone in the triage meeting will be able to help. If you find an interesting profile, or just want to understand how to use them to analyse a performance problem, we encourage you to post a link to the profile (or bug) in #joy-of-profiling where someone will be happy to help. The profile may even be analysed during one of the regular "Joy of Profiling" open sessions that can be found on the Performance Office Hours calendar.

Triage calculator

The Performance Impact Calculator was developed to assist in identifying and applying the performance impact project flag and performance keywords consistently. If you have feedback or would like to suggest changes to this tool, please share these in the #perf-triage Matrix channel.

Triage rotation

The sheriffs are allocated on a weekly basis, which is published here. The rotation is generated by this script.

Templates

New bug

This template is included in the description for new bugs opened in the Core::Performance component. If a bug is opened in another component and then moved to Core::Performance, this template can be used as needed to request additional information from the reporter.

### Basic information

Steps to Reproduce:


Expected Results:


Actual Results:


---

### Performance recording (profile)

Profile URL:
(If this report is about slow performance or high CPU usage, please capture a performance profile by following the instructions at https://profiler.firefox.com/. Then upload the profile and insert the link here.)

#### System configuration:

OS version:
GPU model:
Number of cores: 
Amount of memory (RAM): 

### More information

Please consider attaching the following information after filing this bug, if relevant:

 - Screenshot / screen recording
 - Anonymized about:memory dump, for issues with memory usage
 - Troubleshooting information: Go to about:support, click "Copy text to clipboard", paste it to a file, save it, and attach the file here.

---

Thanks so much for your help.

Moved to Core::Performance

This bug was moved into the Performance component. Reporter, could you make sure the following information is on this bug?

 - For slowness or high CPU usage, capture a profile with http://profiler.firefox.com/ , upload it and share the link here.
 - For memory usage issues, capture a memory dump from about:memory and attach it to this bug.
 - Troubleshooting information: Go to about:support, click "Copy raw data to clipboard", paste it into a file, save it, and attach the file here.

Thank you.

No longer able to reproduce

This bug doesn’t seem to happen anymore in current versions of Firefox. Please reopen or file a new bug if you see it again.

No response from reporter

With no answer from the reporter, we don’t have enough data to reproduce and/or fix this issue. Please reopen or file a new bug with more information if you see it again.

Expected behaviour

This is expected behavior. Please reopen or file a new bug if you think otherwise.

Website issue

According to the investigation, this is a website issue. Please reopen or file a new bug if you think otherwise.