{"id":3002,"date":"2019-03-08T21:27:48","date_gmt":"2019-03-09T02:27:48","guid":{"rendered":"https:\/\/mikeconley.ca\/blog\/?p=3002"},"modified":"2023-12-20T16:25:09","modified_gmt":"2023-12-20T21:25:09","slug":"firefox-front-end-performance-update-14","status":"publish","type":"post","link":"https:\/\/mikeconley.ca\/blog\/2019\/03\/08\/firefox-front-end-performance-update-14\/","title":{"rendered":"Firefox Front-End Performance Update #14"},"content":{"rendered":"\n

We’re only a few weeks away from Firefox 67 merging from the Nightly channel to Beta, and since my last update<\/a>, a number of things have landed.<\/p>\n\n\n\n

It’s the end of a long week for me, so I apologize for the brevity here. Let’s check it out!<\/p>\n\n\n\n

Document Splitting Foundations for WebRender (In-Progress by Doug Thayer)<\/h2>\n\n\n\n

dthayer is still trucking along here – he’s ironed out a number of glitches, and kats is giving feedback on some APZ-related changes. dthayer is also working on a WebRender API endpoint for generating frames for multiple documents in a single transaction, which should help reduce the window of opportunity for nasty synchronization bugs.<\/p>\n\n\n\n

Warm-up Service (In-Progress by Doug Thayer)<\/h2>\n\n\n\n

dthayer is pressing ahead with this experiment to warm up a number of critical files for Firefox shortly after the OS boots. He is working on a prototype that can be controlled via a pref that we’ll be able to test on users in a lab-setting (and perhaps in the wild as a SHIELD experiment).<\/p>\n\n\n\n

Startup Cache Telemetry (In-Progress by Doug Thayer)<\/h2>\n\n\n\n

dthayer landed this Telemetry early in the week<\/a>, and data has started to trickle in. After a few more days, it should be easier for us to make inferences on how the startup caches are operating out in the wild for our Nightly users.<\/p>\n\n\n\n

Smoother Tab Animations (In-Progress by Felipe Gomes)<\/h2>\n\n\n\n

UX, Product and Engineering are currently hashing out the remainder of the work here. Felipe is also aiming to have the non-responsive tab strip bug fixed soon<\/a>.<\/p>\n\n\n\n

Lazier Hidden Window (Completed by Felipe Gomes)<\/h2>\n\n\n\n

After a few rounds of landings and backouts, this appears to have stuck<\/a>! The hidden window is now created after the main window has finished painting, and this has resulted in a nice ts_paint (startup paint) win on our Talos benchmark!<\/p>\n\n\n\n

\"\"
This is a graph of the ts_paint startup paint Talos benchmark. The highlighted node is the first mozilla-central build with the hidden window work. Lower is better, so this looks like a nice win!<\/figcaption><\/figure>\n\n\n\n

There’s still potential for more improvements on the hidden window, but that’s been split out to a separate project \/ bug.<\/a><\/p>\n\n\n\n

Browser Adjustment Project (In-Progress by Gijs Kruitbosch)<\/h2>\n\n\n\n

This project appears to be reaching its conclusion, but with rather unsatisfying results. Denis Palmeiro from Vicky Chin’s team has done a bunch of testing of both the original set of patches that Gijs landed to lower the global frame rate (painting and compositing) from 60fps to 30fps for low-end machines, as well as the new patches that decrease the frequency of main-thread painting (but not compositing) to 30fps. Unfortunately, this has not yielded the page load wins that we wanted1<\/a><\/sup>. We’re still waiting to see if there’s a least a power-usage win here worth pursuing, but we’re almost ready the pull the plug on this one.<\/p>\n\n\n\n

Better about:newtab Preloading (In-Progress by Gijs Kruitbosch)<\/h2>\n\n\n\n

Gijs has a set of patches that should make this possible<\/a>, which will mean (in theory) that we’ll present a ready-to-roll about:newtab when users request one more often than not.<\/p>\n\n\n\n

Unfortunately, there’s a small snag with a test failure in automation, but Gijs is on the case<\/a>.<\/p>\n\n\n\n

Experiments with the Process Priority Manager (In-Progress by Mike Conley)<\/h2>\n\n\n\n

The Process Priority Manager has been enabled in Nightly for a number of weeks now, and no new bugs have been filed against it. I filed a bug earlier this week<\/a> to run a pref-flip experiment on Beta after the Process Priority Manager patches are uplifted later this month. Our hope is that this has a neutral or positive impact on both page load time and user retention!<\/p>\n\n\n\n

Make the PageStyleChild load lazily (Completed by Mike Conley)<\/h2>\n\n\n\n

There’s an infrequently used feature in Firefox<\/a> that allows users to switch between different CSS stylesheets that a page might offer. I’ve made the component that scans the document for alternative stylesheets much lazier, and also made it skip non web-pages, which means (at the very least) less code running when loading about:home and about:newtab<\/p>\n\n\n\n


<\/p>\n

  1. This was unexpected – we ran an experiment late in 2018 where we noticed that lowering the frame rate manually via the layout.frame_rate pref had a positive impact on page load time… unfortunately, this effect is no longer being observed. This might be due to other refresh driver work<\/a> that has occurred in the meantime. ↩<\/a><\/p><\/li><\/ol>","protected":false},"excerpt":{"rendered":"

    We’re only a few weeks away from Firefox 67 merging from the Nightly channel to Beta, and since my last update, a number of things have landed. It’s the end of a long week for me, so I apologize for the brevity here. Let’s check it out! Document Splitting Foundations for WebRender (In-Progress by Doug […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[874,861],"tags":[],"class_list":["post-3002","post","type-post","status-publish","format-standard","hentry","category-firefox-mozilla-2","category-mozilla-2"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/prmTy-Mq","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/posts\/3002","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/comments?post=3002"}],"version-history":[{"count":1,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/posts\/3002\/revisions"}],"predecessor-version":[{"id":3004,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/posts\/3002\/revisions\/3004"}],"wp:attachment":[{"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/media?parent=3002"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/categories?post=3002"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mikeconley.ca\/blog\/wp-json\/wp\/v2\/tags?post=3002"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}