Thursday, July 21, 2016

V8 at the BlinkOn 6 conference

BlinkOn is a biannual meeting of Blink, V8, and Chromium contributors. BlinkOn 6 was held in Munich on June 16 and June 17. The V8 team gave a number of presentations on architecture, design, performance initiatives, and language implementation.

The V8 BlinkOn talks are embedded below.

Real-world JavaScript Performance

Length: 31:41

Outlines the history of how V8 measures JavaScript performance, the different eras of benchmarking, and a new technique to measure page loads across real-world, popular websites with detailed breakdowns of time per V8 component.

Ignition: an interpreter for V8

Length: 36:39

Introduces V8’s new Ignition Interpreter, explaining the architecture of the engine as a whole, and how Ignition affects memory usage and startup performance.

How we measure and optimize for RAIL in V8’s GC

Length: 27:11

Explains how V8 uses the Response, Animation, Idle, Loading (RAIL) metrics to target low-latency garbage collection and the recent optimizations we’ve made to reduce jank on mobile.

ECMAScript 2015 and Beyond

Length: 28:52

Provides an update on the implementation of new language features in V8, how those features integrate with the web platform, and the standards process which continues to evolve the ECMAScript language.

Tracing Wrappers from V8 to Blink (Lightning Talk)

Length: 2:31

Highlights tracing wrappers between V8 and Blink objects and how they help prevent memory leaks and reduce latency.

Monday, July 18, 2016

V8 Release 5.3

Roughly every six weeks, we create a new branch of V8 as part of our release process. Each version is branched from V8’s git master immediately before Chrome branches for a Chrome Beta milestone. Today we’re pleased to announce our newest branch, V8 version 5.3, which will be in beta until it is released in coordination with Chrome 53 Stable. V8 5.3 is filled with all sorts of developer-facing goodies, so we’d like to give you a preview of some of the highlights in anticipation of the release in several weeks.


New Ignition Interpreter

Ignition, V8's new interpreter, is feature complete and will be enabled in Chrome 53 for low-memory Android devices. The interpreter brings immediate memory savings for JIT'ed code and will allow V8 to make future optimizations for faster startup during code execution. Ignition works in tandem with V8's existing optimizing compilers (TurboFan and Crankshaft) to ensure that “hot” code is still optimized for peak performance. We are continuing to improve interpreter performance and hope to enable Ignition soon on all platforms, mobile and desktop. Look for an upcoming blog post for more information about Ignition’s design, architecture, and performance gains. Embedded versions of V8 can turn on the Ignition interpreter with the flag --ignition.

Reduced jank

V8 version 5.3 includes various changes to reduce application jank and garbage collection times. These changes include:
  • Optimizing weak global handles to reduce the time spent handling external memory
  • Unifying the heap for full garbage collections to reduce evacuation jank
  • Optimizing V8’s black allocation additions to the garbage collection marking phase
Together, these improvements reduce full garbage collection pause times by about 25%, measured while browsing a corpus of popular webpages. For more detail on recent garbage collection optimizations to reduce jank, see the “Jank Busters” blog posts Part 1 & Part 2.


Improving page startup time

The V8 team recently began tracking performance improvements against a corpus of 25 real-world website page loads (including popular sites such as Facebook, Reddit, Wikipedia, and Instagram). Between V8 5.1 (measured in Chrome 51 from April) and V8 5.3 (measured in a recent Chrome Canary 53) we improved startup time in aggregate across the measured websites by ~7%. These improvements loading real websites mirrored similar gains on the Speedometer benchmark, which ran 14% faster in V8 5.3. For more details about our new testing harness, runtime improvements, and breakdown analysis of where V8 spends time during page loads, see our upcoming blog post on startup performance.

ES6 Promise performance

V8's performance on the Bluebird ES6 Promise benchmark suite improved by 20-40% in V8 version 5.3, varying by architecture and benchmark.

V8 Promise performance over time on a Nexus 5x


Please check out our summary of API changes. This document gets regularly updated a few weeks after each major release.

Developers with an active V8 checkout can use 'git checkout -b 5.3 -t branch-heads/5.3' to experiment with the new features in V8 5.3. Alternatively you can subscribe to Chrome's Beta channel and try the new features out yourself soon.

Posted by the V8 team