Google's revamped JavaScript engine cures Chrome's stutters

Doing two things at once? Hey, great idea


Google has begun testing a new version of its V8 JavaScript engine for the Chrome browser that improves application performance by executing and compiling JavaScript code at the same time.

"Concurrent code compilation is another step towards reducing latency in Chrome and is part of various ongoing efforts to deliver more responsive, smoother web applications," Google engineer Yang Guo said in a blog post describing the change.

JavaScript is often thought of as an interpreted language because developers deploy their applications in source code form, rather than as compiled binaries. But modern JavaScript engines actually compile JavaScript to machine code on the fly before executing it.

That compilation step can eat up some processor cycles, though, so to minimize delays, V8 doesn't get too fancy about it – at least, not at first. The code is initially compiled in a very straightforward way, without spending much time on performance optimization.

But V8's compilation infrastructure – dubbed "Crankshaft" – is clever. Code that is executed often is actually compiled a second time after the application is already up and running, this time piling on the optimizations to ensure maximum performance.

This optimization phase can be processor-intensive, however, and earlier versions of V8 would run it on the same processing thread that was executing the running application. That meant that if Crankshaft started optimizing a large chunk of code, JavaScript execution could stutter and even appear to pause.

Graph showing how the new Chrome Beta speeds up JavaScript execution

Gaps in the black bar indicate times when JavaScript execution paused.
With earlier versions of Chrome, the circled portion would have been all pause (click to enlarge)

The new Chrome Beta changes that. Compilation now takes place in a separate thread that runs concurrently with the application thread, allowing the precompiled JavaScript to keep chugging while Crankshaft works on optimizing the key bits.

This doesn't just apply to the desktop browser, either. Ever mobile-minded, Google has baked the same changes into the Chrome Beta browser for Android. The result, Guo said, was a speedup of as much as 27 per cent on some JavaScript benchmarks running on a Nexus 5 handset.

The catch, for now at least, is that the revamped V8 is only available in the Chrome Beta channel. Google doesn't announce hard dates for when it plans to promote Chrome builds from Beta to Stable status, but if all goes well in its testing, we can assume that concurrent compilation will be enabled for all Chrome users within the next few months. ®


Other stories you might like

  • Meet Wizard Spider, the multimillion-dollar gang behind Conti, Ryuk malware
    Russia-linked crime-as-a-service crew is rich, professional – and investing in R&D

    Analysis Wizard Spider, the Russia-linked crew behind high-profile malware Conti, Ryuk and Trickbot, has grown over the past five years into a multimillion-dollar organization that has built a corporate-like operating model, a year-long study has found.

    In a technical report this week, the folks at Prodaft, which has been tracking the cybercrime gang since 2021, outlined its own findings on Wizard Spider, supplemented by info that leaked about the Conti operation in February after the crooks publicly sided with Russia during the illegal invasion of Ukraine.

    What Prodaft found was a gang sitting on assets worth hundreds of millions of dollars funneled from multiple sophisticated malware variants. Wizard Spider, we're told, runs as a business with a complex network of subgroups and teams that target specific types of software, and has associations with other well-known miscreants, including those behind REvil and Qbot (also known as Qakbot or Pinkslipbot).

    Continue reading
  • Supreme Court urged to halt 'unconstitutional' Texas content-no-moderation law
    Everyone's entitled to a viewpoint but what's your viewpoint on what exactly is and isn't a viewpoint?

    A coalition of advocacy groups on Tuesday asked the US Supreme Court to block Texas' social media law HB 20 after the US Fifth Circuit Court of Appeals last week lifted a preliminary injunction that had kept it from taking effect.

    The Lone Star State law, which forbids large social media platforms from moderating content that's "lawful-but-awful," as advocacy group the Center for Democracy and Technology puts it, was approved last September by Governor Greg Abbott (R). It was immediately challenged in court and the judge hearing the case imposed a preliminary injunction, preventing the legislation from being enforced, on the basis that the trade groups opposing it – NetChoice and CCIA – were likely to prevail.

    But that injunction was lifted on appeal. That case continues to be litigated, but thanks to the Fifth Circuit, HB 20 can be enforced even as its constitutionality remains in dispute, hence the coalition's application [PDF] this month to the Supreme Court.

    Continue reading
  • How these crooks backdoor online shops and siphon victims' credit card info
    FBI and co blow lid off latest PHP tampering scam

    The FBI and its friends have warned businesses of crooks scraping people's credit-card details from tampered payment pages on compromised websites.

    It's an age-old problem: someone breaks into your online store and alters the code so that as your customers enter their info, copies of their data is siphoned to fraudsters to exploit. The Feds this week have detailed one such effort that reared its head lately.

    As early as September 2020, we're told, miscreants compromised at least one American company's vulnerable website from three IP addresses: 80[.]249.207.19, 80[.]82.64.211 and 80[.]249.206.197. The intruders modified the web script TempOrders.php in an attempt to inject malicious code into the checkout.php page.

    Continue reading

Biting the hand that feeds IT © 1998–2022