1
HolyJit: A New Hope
tl;dr: We believe there is a safer and easier way of writing a Jit. Current State Today, all browsers’ Jits share a similar design. This ...
Mozilla Blog
Perspectives on the internet from Mozilla
- Popular posts
- 317
- Total points
- 104,554
- HN comments
- 52,848
- Rank
- #4 company
Visit blog.mozilla.org → RSS feedOn Hacker News Apr 2012 – Sep 2026
Web & Frontend 172Security & Privacy 103Tech Industry & Business 70Software Engineering 66Society, Policy & Culture 47Systems & Performance 28
2
Update on Multi-Process Firefox
About four months ago, we launched multi-process Firefox to a small group of Firefox 48 users. Shortly after the carefully measured roll-out, we increased to approximately 50% of our user ...
3
AdBlock Plus’s effect on Firefox’s memory usage
[Update: Wladimir Palant has posted a response on the AdBlock Plus blog. Also, a Chrome developer using the handle “Klathmon” has posted numerous good comments in the Reddit discussion of this post , explaining why ad-blockers are inherently CPU- and memory-intensive, and why integrating ad-blocking into a browser…
4
Firefox fixes save gigabytes of memory on image-heavy pages
Lots of important MemShrink stuff has happened in the last 27 days: 22 bugs were fixed , and some of them were very important indeed.
5
What’s Next for Multi-Process Firefox
By Asa Dotzler and Brad Lassey Electrolysis is the project name for Mozilla's efforts to split Firefox into multiple processes to improve responsiveness, stability, and security. The first phase of ...
6
Firefox Keeps Getting Faster
Web browsing is a pervasive part of modern life, and the quality of the experience directly affects the quality of your day. When your tasks are disrupted
7
64-bit Firefox is the new default on 64-bit Windows
Users on 64-bit Windows who download Firefox can get our 64-bit version by default. That means you get a more secure version of Firefox, one that also crashes a whole lot less . How much less? In our tests so far, 64-bit Firefox reduced crashes by 39% on machines with 4GB of RAM or more.
8
Firefox 41 will use less memory when running AdBlock Plus
Last year I wrote about AdBlock Plus’s effect on Firefox’s memory usage . The most important part was the following.
9
Update on Metro
Earlier this week, I asked our engineering leads and release managers to take the Windows Metro version of Firefox off the trains. The team is solid and did good work, ...
10
What Flips Your Bit: Cosmic Ray Errors at Mozilla
(“This Week in Glean'' is a series of blog posts that the Glean Team at Mozilla is using to try to communicate better about our work. They could be release ...
11
Please grow your buffers exponentially
If you record every heap allocation and re-allocation done by Firefox you find some interesting things. In particular, you find some sub-optimal buffer growth strategies that cause a lot of heap churn.
12
Firefox finally plugs the leak
Leaky add-ons are a big problem, but there’s been lots of action relating to them recently. What follows is a summary of the situation and a request for help from currently Nightly testers who use add-ons.
13
On mutex performance and WTF::Lock
One of the things I’ve been doing this quarter is removing Gecko’s dependence on NSPR locks . Gecko’s (non-recursive) mutexes and condition variables now use platform-specific constructs, rather than indirecting through NSPR. This change makes things smaller, especially on POSIX platforms, and uses no dynamic memory…
14
Generational GC has landed in Firefox
Big news: late last week, generational garbage collection landed. It was backed out at first due to some test failures, but then re-landed and appears to have stuck.
15
Slimmer and faster JavaScript strings in Firefox
Since Brendan Eich wrote the first SpiderMonkey version in 1995, there have been many, many changes to its internal string representation. New string types like ...
16
Firefox 15 plugs the add-on leaks
Firefox 15 prevents most memory leaks caused by add-ons, including Firebug. For many users with add-ons installed this will significantly reduce Firefox’s memory consumption, without requiring upgrades to those add-ons.
17
Staring at the Sun: Dalvik vs. Asm.js vs. Native
As many of you are probably already aware, Mozilla has recently gotten into the mobile OS space with Firefox OS. Firefox OS is built using ...
18
An even slimmer pdf.js
TL;DR: Firefox’s built-in PDF viewer is on track to benefit from additional large reductions in memory consumption when Firefox 33 is released in mid-October.
19
Asm.js AOT compilation and startup performance
With the recent announcement of a commercial game shipping using Emscripten and asm.js , I thought it’d be a good time to explain how asm.js is executed in Firefox and some of the load-time optimizations we’ve made since the initial landing of OdinMonkey in March. (OdinMonkey is an optimization module inside Mozilla’s…
20
Firefox, Heal Thyself
This week's release of Firefox includes the beginning of a pretty cool feature. The Firefox Health Report is a new system we've built to log basic health information about your ...
21
I rewrote Firefox's BMP decoder
Recently I’ve been deliberately working on some areas of Firefox I’m unfamiliar with, particular relating to graphics. This led me to rewriting Firefox’s BMP decoder and learn a number of interesting things along the way.
22
A big step towards Firefox generational and compacting GC
People frequently ask me for status updates on generational GC, and I usually say I’ll tell them when something notable happens. Well, something notable just happened: exact rooting landed .
23
What Does the OS X Activity Monitor’s “Energy Impact” Actually Measure?
[ Update : this post has been updated with significant new information. Look to the end.]
24
Firefox Beta for Windows 10 on Qualcomm Snapdragon Now Available
Today, we’re excited to report the availability of our ARM64-native build of Firefox for Snapdragon-powered Windows 10 Always Connected PCs in our beta release channel, a channel aimed at developers or early tech adopters to test upcoming features before they’re released to consumers.
25
Fix your damned data races
Nathan Froyd recently wrote about how he has been using ThreadSanitizer to find data races in Firefox, and how a number of Firefox developers — particular in the networking and JS GC teams — have been fixing these.
26
Porting rr to x86-64
(TL;DR: rr from git can record and replay 64-bit programs. Try it for yourself !)
27
Firefox 32-bit Linux Support to End in 2026
For many years, Mozilla has continued to provide Firefox for 32-bit Linux systems long after most other browsers and operating systems ended support. We made this choice because we care ...
28
Firefox OS Update Adds New Features, Performance Improvements
Just weeks after the first Firefox OS phones hit the market, an update is being made available adding new features, support for a number of new languages and significant performance ...