In the latest Chrome Beta release, Google has enabled concurrent compilation, which offloads an important part of the compilation process to a background thread to deliver better performance for web apps.
Where does the performance boost come from?
The initial "compilation phase is fast but doesn't focus on optimising the code, just on getting it done quickly", Guo wrote.
The switch to concurrent compilation tackles this issue, he said.
To demonstrate the performance increase concurrent compilation makes possible Google produced two graphs showing V8 performance when running Mandreel, part of the Octane 2.0 benchmark suite, on the Nexus 5 phone.
The first graph shows V8 running without concurrent compilation. V8 is fully occupied with optimising a large piece of code, causing an execution pause of more than 600ms.
Enabling concurrent compilation, allows the optimisation to take place in a background thread without pausing the application's execution, as seen below.
Concurrent compilation improved the Mandreel score of Octane 2.0 by 27 percent on a Nexus 5, Guo wrote, and made graphic-intensive applications such as the Epic Citadel Demo run even smoother in Chrome.
The concurrent compilation feature available in the Chrome Beta release will be added to the stable release of the browser at a later date.
Firefox will also move the entire just-in-time compilation process off the main thread in the forthcoming Firefox 29 release, currently available to test through its Aurora release channel.