Firefox 89 delivers higher speeds – Firefox 90 today added SmartBlock 2.0

The red panda of the Internet continues to improve.
Enlarge it / The red panda of the Internet continues to improve.

Today, Mozilla launched Firefox 90. The latest version of Mozilla’s increasingly privacy-focused browser adds improved print-to-PDF functionality, individual exceptions to HTTPS-only mode, about: third-party pages to help identify compatibility issues introduced by party apps, and a new SmartBlock feature that increases protection from cross -site tracking while ensuring website logins remain functional.

There’s also a new background update for Windows, which allows small background apps to check for, download, and install Firefox updates when the browser isn’t running.

SmartBlock 2.0

The latest version of Mozilla’s built -in SmartBlock privacy feature makes it easier for users to maintain their tracking protection settings without changing individual websites. The updated version appears to target Facebook entry, which is increasingly being used on the web as a third -party authentication and login tool.

Firefox blocks Facebook scripts by default, because Mozilla Disconnect partner (correctly) identifies Facebook domains in a list of known third -party trackers. Unfortunately, blocking Facebook scripts also means breaking third -party Facebook logins – for example, the Facebook login feature found on

With SmartBlock 2.0, Facebook scripts are disabled on third -party websites, as before – but when users click the “Continue with Facebook” option, specific and intentional user interactions with Facebook scripts cause SmartBlock 2.0 to release them. The lifting of the block happened just in time to allow for a successful Facebook authentication login – without users having to lower their tracking protection settings.

Firefox is faster

Mozilla’s internal metrics show a significant increase in speed in 2021-Firefox 89 last month was 10-30 percent faster than previous versions, according to Mozilla’s own testing. Specifically, the Mozilla team mentioned improvements in the following areas:

  • Type in the URL bar or in a document editor (for example, Google Docs, Office 365)
  • Open a webpage menu (like the file menu in Google Docs)
  • Keyboard controls in browser -based video games

To discuss performance and profitability goals more concretely, Mozilla defines three levels of browser response: instantaneous, perceptible lag, day jank, with maximum latency limits of 50 ms and 1,000 ms for the first two. Mozilla continues to say so jank meaning not only longer delays, but the entire website – and in the worst case, the browser UI itself – becoming unusable for more than a second at a time.

Impressively, Firefox 89 manages a instantaneous response to events more than 40 percent of the time – up from just 30 percent in Firefox 86.

Just a second

For instantaneous response, the calculations performed by the browser itself aren’t the only problem – no matter how fast the browser generates new data, the user can’t actually see it until the monitor displays it. With a special 60Hz monitor refresh rate, that means new frames are displayed approximately every 17 ms-giving the browser just three frames to reach the 50 ms goal for this response level.

In previous versions of Firefox, user input would occur at frame 0, and the “paint” process in which the browser drew new content would then occur at frame 1 – leaving the composition (when new painted content is actually submitted to the operating system and displayed on the user’s monitor) occurs no earlier than frame 2. Those are the three frames we can load within the 50 ms time limit set by Mozilla for instantaneous respond!

Starting with Firefox 89, the Firefox pipeline update proposed by Markus Strange could significantly improve the situation – now, painting can occur in the same framework as user input occurs, make compositing maybe an earlier framework. This makes the maximum responsive interaction about 17 ms faster than before-a strong third of the self-charged instantaneous the window.

A small but visible delay

A large number of perceived browser delays are due to time spent in JavaScript code – often, because JavaScript engine developers spend more time synthetic benchmarking games than optimizing real -world web applications and frameworks.

Targeting commonly used websites directly allows Mozilla to better investigate performance issues in SpiderMonkey, Firefox’s JavaScript engine. Experimenting to improve performance on real -world websites instead of benchmarks resulted in an increase in array iterators, which improved performance starting in Firefox 89.

Mozilla’s forecast continues SpiderMonkey’s significant improvement throughout 2021, noting an improved object structure architecture and faster loops as two examples. Ted Campbell, Iain Ireland, Steve Fink, Jan de Mooij, and Denis Palmeiro received Mozilla’s many thanks for their many contributions to SpiderMonkey’s performance.


Mozilla’s worst but funniest performance category, jank, got its own set of improvements – most notably, the new Background Hang Reporter. Thanks in part to the hard work of Florian Quèze and Doug Thayer, Mozilla now gets special telemetry information when it tanks the browser performance – including traces of key thread strings often seen in Firefox’s master process.

The new tools already provide insights and performance improvements – for example, Mozilla has found that accessibility features are unnecessarily activated for most Windows users with touch screens. Accessibility features are very important for users who need them, but they show significant extra work for the browser when active.

Thanks in part to help from James Tea, the number of users with unnecessary accessibility features is significantly reduced – and the number of hang reports is declining along with it.


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