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 inline strings (more on this below) and ropes were added to save memory and improve performance, but the character representation never changed: string characters were always stored as a sequence of UTF-16 code units. The past two months I
The Baseline Compiler Has Landed
This wednesday we landed the baseline compiler on Firefox nightly. After six months of work from start to finish, we are finally able to merge the fruits of our toils into the main release stream. What Is The Baseline Compiler? Baseline (no, there is no *Monkey codename for this one) is IonMonkey’s new warm-up compiler. It brings performance improvements in the short term, and opportunities for ne
Parallel JS lands · baby steps
This blog is where I post up various half-baked ideas that I have. All PostsCategoriesGitHubTwitterRSS/Atom feedsSelected posts: The borrow checker withinEmpathy in open source: be gentle with each other The first version of our work on ParallelJS has just been promoted to mozilla-central and thus will soon be appearing in a Nightly Firefox build near you. I find this pretty exciting. In honor of
Firefox Nightly (22) に ES6のArrow Function来たる - fragmentary
そもそもES6に入ってるのも知らなかったので、2日前にmozilla-inboundにチェックインされててだいぶ驚いた。 で、Nightlyに入るのを待つこと2日弱、ようやく入ったので試してみた。 おお動く。そしてこのJavaScript書いてない感がすごい。 thisがレキシカルにboundされるようなのでイベントリスナとかで楽そうだー。 追記 (2013-03-21) こんなのよりもっとずっと詳しく丁寧な解説が公開されたのでそちらをどうぞ！ Firefox 22(Nightly) で ArrowFunction が実装されたが、扱いが難しい - hogehoge @teramako
JIT Inspector – Get this Extension for 🦊 Firefox (ja)
The JIT inspector instruments generated JavaScript JIT code to record information about how much code has run and how well it was optimized: - How many times individual operations have been executed. - Whether operations executed entirely in JIT code (fast) or as calls into the underlying virtual machine (slow). - Precision of type information inferred for each operation, as used for optimization.
Mozilla’s New JavaScript Value Representation < Rob Sayre's Mozilla Blog
Here at Mozilla, we have many monkeys. One such effort, JaegerMonkey, is focused on revamping the baseline performance of our JS Engine. That effort is going really well. On the SunSpider benchmark, JaegerMonkey is starting to pull away from the Mozilla trunk’s JS Engine. Both are faster than the engine that ships in Firefox 3.6. JaegerMonkey is not a total rewrite, but it does change some fundame
677272 - (JITHardening) JIT hardening
Chris Rolph and Yan Ivnitskiy from Matasano have been discussing JIT spray mitigations with us. Quoting Blazakis, 2010: "JIT spraying is the process of coercing the JIT engine to write many executable pages with embedded shellcode." There are a number of patches and performance results drafted up that implement the following laundry-list of mitigation techniques, as enumerated in their black hat p
David Mandelin's blog » JS Team Update 11/1
For a while, I was pretty swamped, with not enough time to do a regular team newsletter. And then, I figured I’d have to go back over the past 2 months of activity to sort out everything that happened so I could write a proper giant update. But, I realize that’s way too hard and I’ll never get to it, so instead I’ll just do a brief update as of today: Terrance Cole joined the team to work on GC ef
SpiderMonkey is on a diet – Nicholas Nethercote
One thing I’ve learnt while working for Mozilla is that a web browser can be characterized as a JavaScript execution environment that happens to have some multimedia capabilities. In particular, if you look at Firefox’s about:memory page, the JS engine is very often the component responsible for consuming the most memory. Consider the following snapshot from about:memory of the memory used by a s
Latest topics > JavaScriptでsleepしたい、を実現する方法（require JavaScript 1.7） - outsider reflex
Latest topics > JavaScriptでsleepしたい、を実現する方法（require JavaScript 1.7） 宣伝。日経LinuxにてLinuxの基礎？を紹介する漫画「シス管系女子」を連載させていただいています。 以下の特設サイトにて、単行本まんがでわかるLinux シス管系女子の試し読みが可能！ « 自宅マシンがどうにもならないレベルで逝ってしまったようだ Main 「本当に言いたかった事は」 » JavaScriptでsleepしたい、を実現する方法（require JavaScript 1.7） - Feb 20, 2009 中野さんが、JavaScriptにはsleep（一定時間待ってから次の処理に進むという命令文）が無いせいでテストを書くのに難儀したという話を書かれているけれども。まさにこれをどうにかしたくて、UxUは進化してきたようなものと言える。 知
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Defining JavaScript functions, the ES6 way // by Paul Rouget
How Firefox Makes Your JavaScript Run Fast | by Nathan Froyd @froydnj
Parallel JS (River Trail): soon in Firefox
715419 - consider specializing Array.prototype.sort when given the comparator is "return arg1 - arg2"
789373 - use the new --disable-ion flag for specific b2g-related builds
725909 - Make Maps and Sets iterable
David Mandelin's blog » Mozilla JS Development Newsletter 1/25/2012-2/29/2012
List of Accepted Papers 论文收录 | PLDI 2012
698201 - Remove tracer
Proxy で 固定長配列 - jsdo.it - Share JavaScript, HTML5 and CSS