Web Performance APIs Rapidly Become W3C Recommendations

In this IE Blog post article, I discuss how the W3C Web Performance APIS are rapidly becoming W3C Recommendations with interoperable support for all major web browsers.

The W3C Web Performance Working Group recently published three specifications as W3C Recommendations with full implementations from all major browser vendors, advancing developers’ ability to accurately measure the performance of Web applications and make the Web faster. Over the last three years, companies including Microsoft, Google, Mozilla, Intel, Facebook, and others have been working towards standardizing the Navigation Timing, High Resolution Time, and Page Visibility interfaces in the Working Group. Rapid adoption of these recommendations demonstrates what’s possible when the industry and community come together through the W3C.

To make the Web faster, developers need the ability to accurately measure the performance characteristics of Web applications and the ability to effectively use the underlying hardware to improve the performance of their applications. To solve these problems, the Web Performance Working Group worked on 15 different specifications that address those issues. The table below shows the maturity level of all the specifications currently edited by the Working Group.

Web Performance Spec Status 5_22_2013

The Navigation Timing, Resource Timing, User Timing, and Performance Timeline specifications help developers accurately measure the timing of the navigation of the document, fetching of resources on the page, and developer script execution. Prior to these APIs, this data wasn’t easily obtainable. Navigation Timing was published as a W3C Recommendation, and all major browser vendors support it. The other three interfaces are currently at the Candidate Recommendation stage awaiting two full implementations from browser vendors. IE10 is currently the only browser that implements all of these interfaces, however, other vendors are working on implementations.

To ensure these performance metrics are measured in the most accurate way possible, the High Resolution Time specification allows developers to measure operations with sub-millisecond accuracy. This interface not only benefits accurate measurements of performance metrics, but also allows better frame rate calculations and synchronization of animations or audio cues. This interface has been published as a W3C Recommendation, with all major browser vendors implementing the performance.now() method defined in the specification.

The Page Visibility API allows for programmatically determining the current visibility state of the page. Developers can use this data to make better CPU- and power-efficiency decisions, e.g., throttling down activity when the page is in the background tab. This specification has also been published as a W3C Recommendation, with all major browser vendors implementing it.

The Timing Control for Script-Based Animations, and Efficient Script Yielding specifications help developers write more CPU- and power-efficient Web applications. The requestAnimationFrame API, from the Timing Control for Script-Based Animations specification, allows for creating more efficient JavaScript animations. All browser vendors fully support this interface, with the Working Group actively working on publishing this specification as a Candidate Recommendation. The setImmediate API, from the Efficient Script Yielding specification, allows developers to efficiently yield control flow to the user agent and receive an immediate callback, efficiently leveraging the CPU. IE10 is the first browser to implement this interface.

This year the Working Group also started to look at new ideas, with editor’s drafts of those ideas currently being discussed in the Working Group. The Beacon API is intended to help scripts asynchronously transfer data to a Web server without blocking the unload event, which can negatively impact the perceived performance of the next navigation. The Resource Priorities API defines a means for Web developers to give the browser hints on the download priority of resources to help improve the page load time. As a corollary to the Timing specs, the Navigation Error Logging and Resource Error Loggingspecifications help developers understand the errors and availability of their applications. The Navigation Timing Level L2 specification adds High Resolution Time and Performance Timeline support to Navigation Timing, and High Resolution Time L2 specification adds Web Worker support. These are just some of the drafts the Working Group is currently defining, with more specification drafts on Prerender and other diagnostics areas forthcoming.

The W3C Web Performance Working Group is a great example of how quickly new ideas can become interoperable standards that developers can depend on in modern HTML5-enabled browsers. Together with industry and community leaders who participate in the Working Group, we hope to continue to make rapid progress on interoperable standards that will help developers make the Web faster.

Thanks,
Jatinder Mann
Internet Explorer Program Manager

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W3C Web Performance: Continuing Performance Investments

I discuss the W3C Workshop on Performance in this IE Blog post article.

The W3C Web Performance working group recently held the W3C Workshop on Performance on Thursday, November 8, 2012. The goal was to hear current challenges and proposals for new performance ideas for the working group to consider. There were 45 attendees from 21 organizations, including most browser manufactures (Microsoft, Google, and Mozilla), hardware organizations (Intel, Qualcomm, Nokia, Motorola), network organizations (Cisco, Akamai, F5), and top Web properties (GMail, Google Search, Bing, NetFlix, LinkedIn, Zynga, and more). Details on the presentations and discussions from the workshop can be found in this report.

Providing the ability to accurately measure the performance characteristics of Web applications and create power- and CPU-efficient applications is critical to Web performance. The W3C Web Performance working group worked on achieving those goals in its recently completed second chartered period. In under two years, the working group rapidly standardized and modern HTML5-enabled Web browsers implemented these eight interfaces: Navigation Timing, Resource Timing, User Timing, Performance Timeline, Page Visibility, Timing control for script-based animations, High Resolution Timeand Efficient Script Yielding. Internet Explorer 10 is the first browser to support all eight of these new APIs.

The working group has since been focused on gathering data to understand which areas to focus on in its third chartered period. In addition to the Workshop on Performance, the working group has invited performance experts to its weekly conference calls and has broadly surveyed the performance community on ideas.

Based on all the data gathered these past few months, the Web Performance working group has decided to focus on the following areas in the third chartered period:

  • Timing Metrics The working group will continue to improve the Timing interfaces, Navigation Timing, Resource Timing, User Timing and Performance Timeline. For example, we will consider providing Web workers support in the Timing interfaces and including information on video byte ranges in Resource Timing.
  • Efficient Script Yielding The working group will continue to improve on power- and CPU-efficient APIs, like the setImmediate API defined in the Efficient Script Yielding specification.
  • Prerender The working group will standardized the prerender feature which allows navigations to appear almost “instantly” in cases where the browser has high confidence that a user will visit an URL. The way this feature would work is that the browser will proactively navigate to a Web page in a hidden tab, when it sees the “prerender” link type or has high confidence that user will visit that link. When the user does visit that link, the browser will make the hidden tab visible, giving the perception of instant navigation.
  • Resource Priorities Today, browsers download resources in the priority order that they believe are most efficient in helping the page load occur quickly. However, developers may want to prioritize some resources over others. For example, downloading images above the fold may be of higher priority than those below the fold. Though, developers can give some hints to the browser on download priority, like using the “defer” and “async” attributes in markup, these concepts do not include most resources. To help the browser prioritize downloading resources, the working group is expanding the charter to include interoperable means for developers to give the browser hints on the download priority of resources.
  • Diagnostics Interfaces Developers are interested in learning how to make their Web applications faster and less error prone. The working group is expanding the charter to include interoperable means for developers to get browser diagnostics information on their Web applications. For example, using these interfaces a developer could understand where memory is leaking or what errors users are encountering on their Web applications.
  • Beacon Today, analytics scripts will block the current page from unloading by running in a loop in order to confirm that analytics data has been sent to a Web server. This behavior will delay the navigation to the next page, resulting in user perception of poor performance. To help developers avoid that pattern, the working group is expanding the charter to include an interoperable means for developers to asynchronously transfer data from the browser to a Web server, with a guarantee from the browser that the data will eventually be sent.
  • Display Performance Developers are interested in understanding the performance of their games and animations.

    The working group is expanding the charter to include interoperable means for developers to get frame rate and throughput of the display type of information.

This working group is a great example of how quickly new ideas can become interoperable standards that developers can depend on in modern HTML5-enabled browsers. Together with industry and community leaders who participate in the working group, we hope to continue to make rapid progress on interoperable standards that will benefit developers and everyone who uses the Web.

Jatinder Mann, Internet Explorer, Program Manager