Apple looking to further boost Safari JavaScript performance with upgrades to Nitro engine


Apple is working on boosting JavaScript performance in Safari across Mac and iOS, as revealed in recent builds of WebKit, the open source rendering engine Safari is built upon.

The WebKit wiki shows an update to the Nitro JavaScript engine codenamed “FTL JIT” that make Safari’s JavaScript performance much faster than Chrome, and comparable to Firefox. Info World reports:

FTLJIT is still considered experimental, so although it’s being made available in the OS X port of WebKit by default, it’s not actually turned on yet — it has to be enabled through command-line flags.

So far, the speed boosts afforded by FTLJIT vary but are intriguing. AreWeFastYet, the JavaScript testing site founded by Mozilla’s JavaScript team, ran its own benchmarks on 64-bit OS X and found the LLVM-powered build of WebKit to be markedly faster than Chrome on some benchmarks. That said, Firefox running asm.js versions of the same benchmarks still consistently beat WebKit.

While speeding up JavaScript is a technical detail, it has a direct impact on the user experience, as most modern websites today make heavy use of JavaScript for features like dynamic loading of content without page refresh, animating elements on the webpage, etc.

The Nitro JavaScript engine, introduced in 2011 in iOS, improved JavaScript performance by a factor of two, and a combination of the improvements in the engine as well as processor advancement will further contribute to faster performance.

Apple however hasn’t made the Nitro engine available to third-party browsers and in-app web views in apps like Twitter, Facebook etc., so it’s uncertain whether the FTL JIT updates would benefit these browsers or not.

We hope that Apple is working to bring these JavaScript improvements to iPhone and iPad as part of iOS 8.

[via MacRumors]