Performance

Performance

Mozilla's performance program focuses on improvements to the Gecko platform and the Firefox Desktop, Firefox for Android, and Firefox OS products.

Projects

Active

Incremental Cycle Collection (ICC)

Product impact	[DESKTOP] [MOBILE] [B2G]
Goal	Implement incremental cycle collection to reduce1 cycle collector pauses in the Firefox UI. 1Reduction in cycle collector pauses will be measured with the CYCLE_COLLECTOR_FULL Telemetry probe. The degree of reduction that can be achieved is currently unclear.
Duration	TBD
Team	Andrew McCreight (lead)
Progress reports	TeamStatus: Andrew McCreight
Work	bug 850065
Dependencies
Notes

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Keep JS-accessible APIs from blocking the main thread

Product impact	[DESKTOP] [MOBILE] [B2G]
Goal	Refactor existing and provide new JS APIs to either migrate services, components, and add-ons off the main thread or at least prevent them from blocking the main thread.
Duration	TBD
Team	David Rajchenbach-Teller (lead), Paolo Amadini
Progress reports	TeamStatus: David Rajchenbach-Teller
Work	Bugzilla query
Dependencies
Notes	This project focuses on JS-accessible APIs in the context of Web Workers.

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Profiler Backend for Mobile

Product impact	[MOBILE] [B2G]
Goal	Accurate1, crash-free, deadlock-free, low overhead2 stack unwinding for the SPS profiler for Firefox for Android and Firefox OS. [1]The correct sequence of code return addresses on the stack, ideally without the unwind terminating before it gets back to main(). [2]Average unwind cost of 500 microseconds for a 30-frame backtrace on one core of a 1 GHz Cortex A9
Duration	TBD
Team	Julian Seward (lead), Benoit Girard, Mike Hommey
Progress reports	Julian Seward's blog, TeamStatus: Julian Seward, Benoit Girard, Mike Hommey
Work	bug 863453
Dependencies
Notes	May impact desktop Linux as well.

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Reducing time to first paint - Phase 1

Product impact	[DESKTOP]
Goal	A 10% reduction1 in time between XRE_Main and first paint2 during cold starts3 on Windows 7 with no extensions installed4, on reference slow hardware5, 30 seconds after an OS reboot. [1]Currently, after an OS restart, XRE_Main to firstPaint takes about 4.2 seconds on the reference hardware. A 10% reduction will be ~400ms. [2]XRE_Main as the starting point to exclude the impact of loading Firefox binaries as they grow bigger with every release. First paint to exclude the impact of Yoric's session store refactor work. [3]Cold start because a lot of the work will be focused on reducing the amount of I/O done during startup. [4]No extensions to exclude the impact of Irving's Add-on Manager work. [5]The reference hardware is a recent, slow Win7 laptop with an AMD C-50 dual-core @ 1 GHz, magnetic HDD, and 2GB shared RAM. A slow Windows laptop is used because it is consistently slow and can be easily debugged.
Duration	TBD
Team	Vladan Djeric (lead)
Progress reports	Vladan Djeric's blog, TeamStatus: Vladan Djeric
Work	bug 810156
Dependencies	Replace Add-on Manager SQLITE with JSON file project
Notes	Will measure with about:telemetry on reference hardware as aggregate Telemetry includes both warm and cold starts and a variety of hardware confirgurations.

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Replace Add-on Manager SQLITE with JSON file

Product impact	[DESKTOP] [MOBILE]
Goal	Goal: Reduce Add-on Manager impact on start-up time1 and runtime pauses2 by removing SQLITE database from XPI Provider and Add-on Repository and replacing with JSON3. 1Start-up time reduction by reducing the amount of I/O required before first paint. 2Runtime pause reduction by reducing I/O required during add-on up-to-date checks and updates, and making sure as much as possible is off main thread. 3New implementation will do no blocking I/O except minimal loading of required data during start-up.
Duration	6 weeks (approx week of May 27, 2013)
Team	Irving Reid (lead), Felipe Gomes
Progress reports	Irving Reid's blog, TeamStatus: Irving Reid, Felipe Gomes
Work	bug 853388, bug 853389
Dependencies
Notes

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Smooth Tab Animation

Product impact	[DESKTOP]
Goal	Reasonably1 smooth tabstrip animation on modern low-end AMD/Intel CPUs. The specific focus will be on use cases 1-8 defined below. New tab open of about:blank where other tabs are unaffected. (not common, this is our raw baseline) Tab close where other tabs are unaffected, and where the newly focused tab is empty. (also raw baseline) New tab open - with thumbnails preview - where other tabs are unaffected. Tab close where other tabs are unaffected, where the newly focused tab is heavy (e.g. GMail). 5-8. Same as the above, when other tabs are affected (shrunk/expanded) - up to 10 changing tabs. 1The last 70% of the animation is not lower than 50fps.
Duration	TBD
Team	Avi Halachmi (lead), Tim Taubert
Progress reports	Avi Halachmi's blog, TeamStatus: Avi Halachmi
Work	bug 815354
Dependencies	OMTC
Notes

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Network Cache Rewrite

Product impact	[DESKTOP] [MOBILE] [B2G]
Goal	A cache that causes no main thread I/O jank (directly or indirectly via locks)1, and that avoids losing the entire cache during crashes or unclean shutdown.2 [1]Currently the cache causes jank (sometimes in excess of 1 second) via main thread waiting while cache thread holds lock and does I/O. [2]Cache is currently thrown away unless clean shutdown. Cache loss rates per startup are 9% on windows desktop, 11% OSX, 22% Linux desktop, 25% metro. New design will keep all cache entries and detect corruption on a per-entry basis.
Duration	Goal is to have new code in production by end of Q4 2013
Team	Honza Bambas (lead), Michal Novotny, Jason Duell (manager)
Progress reports
Work	bug 877301
Dependencies
Notes	Cache rewrite project wiki page

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Downloads API Rewrite

Product impact	[DESKTOP]
Goal	To improve responsiveness when downloads are started, by removing the main-thread I/O caused by access to "downloads.sqlite". The concrete goal is to ensure that SQL statements involving moz_downloads no longer appear in the "slow SQL" Telemetry dashboard.
Duration	Late July / early August for reaching the initial goal in Nightly. Probably another month or two (with lower bandwidth) for follow-ups.
Team	Paolo Amadini (lead), Raymond Lee, Felipe Gomes
Progress reports	firefox-dev mailing list, weekly updates tool.
Work	bug 825588
Dependencies
Notes	The project should include a follow-up time frame to accommodate any changes identified after Firefox for Desktop has migrated to the new API, as well as handle requests to facilitate other Mozilla products and add-ons to migrate to the new API.

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On Hold

Shutdown

Product impact	[DESKTOP]
Goal	Ensure 95% of Firefox desktop instances shutdown in 3 seconds or less.
Duration	TBD
Team	Benoit Girard (lead)
Progress reports	Benoit Girard's blog, TeamStatus: Benoit Girard
Work	bug 819063
Dependencies
Notes

Hold reason	Resource availability

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Proposals

Project proposals should be listed on the perf etherpad.

Archive

Completed/terminated projects are listed in the project archive.

Tools

• Telemetry
• jydoop: Efficient and Testable hadoop map-reduce in Python (Introduction from Benjamin Smedberg)
• SPS Profiler
• Buildbot/Talos

Communication

Communication Type	Mechanism	Audience
Announcements	dev-platform list	all
Meetings	First Thursday of each month, 1pm PT Dial-in: Audio-only conference# 99355 People with Mozilla phones or softphones please dial x4000 Conf# 99355 US/Toll-free: +1 800 707 2533, (pin 4000) Conf# 99355 US/California/Mountain View: +1 650 903 0800, x4000 Conf# 99355 US/California/San Francisco: +1 415 762 5700, x4000 Conf# 99355 US/Oregon/Portland: +1 971 544 8000, x4000 Conf# 99355 CA/British Columbia/Vancouver: +1 778 785 1540, x4000 Conf# 99355 CA/Ontario/Toronto: +1 416 848 3114, x4000 Conf# 99355 UK/London: +44 (0)207 855 3000, x4000 Conf# 99355 FR/Paris: +33 1 84 88 37 37, x4000 Conf# 99355 Gmail Chat (requires Flash and the Google Talk plugin): paste +1 650 903 0800 into the Gmail Chat box that doesn't look like it accepts phone numbers SkypeOut is free if you use the 800 number Vidyo: Performance IRC: #perf Agenda: https://etherpad.mozilla.org/perf	all
Meeting summaries	this wiki	all
Micro status	TeamStatus	devs
Weekly status	Mozilla Status Board	devs

Progress Reports

2013
June 2013 May 2013

People

list required competencies for people and, once defined, the people working on project. note that not all of these competencies will be required for every project

Project Champion
Program Management	Lawrence Mandel
Product
Engineering	Taras Glek, Vladan Djeric

References

Related Projects

• MemShrink

Archive

Old Projects

• Mobile Startup Shrink
• Startup Performance
• Front-end Performance (i.e., responsiveness)
• Add-on Performance
• Snappy
• Mobile Performance Info

Tools

• Codesighs - a tool which analyzes code and data size.
• Performance:Tools. For measuring performance. Tip o' the propeller-cap to Daniel Roberts (zuperdee@penguinpowered.com) for the pointers.
• Performance:Probes. Project to integrate a system of performance probes into Gecko.

Documentation and Presentations

• Code Footprint Performance:Footprint_Reduction_Techniques explains common bad patterns and how to correct them.
• Performance:Profiling_JuJu. Things you should know about doing profiling. Tips and tricks for some of the tools, and lots of other Good Things To Know.
• Profiling and leak analysis on the Mac.
• Performance:Footprint_Tools. Presentation on footprint tools
• Performance:Startup slides Presentation on general performance tools
• Performance:Leak_Tools. Presentation on memory leaks detection tools
• Mac Performance Tools Presentation on performance tools that work on Mac