Performance Timeline Level 2 (original) (raw)

Abstract

This specification extends the High Resolution Time specification [HR-TIME-2] by providing methods to store and retrieve high resolution performance metric data.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

Performance Timeline Level 2 replaces the first version of [PERFORMANCE-TIMELINE] and includes:

• Extends the base definition of the Performance interface defined by [HR-TIME-2];
• Exposes PerformanceEntry in Web Workers [WORKERS];
• Adds support for performance observers.

The Working Group expects to demonstrate 2 implementations of the features listed in this specification by the end of the Candidate Recommendation phase.

No changes were done since the previous publication.

This document was published by the Web Performance Working Group as a Candidate Recommendation. This document is intended to become a W3C Recommendation. If you wish to make comments regarding this document, please send them topublic-web-perf@w3.org (subscribe,archives) with [Performance Timeline] at the start of your email's subject.W3C publishes a Candidate Recommendation to indicate that the document is believed to be stable and to encourage implementation by the developer community. This Candidate Recommendation is expected to advance to Proposed Recommendation no earlier than 10 January 2017. All comments are welcome.

Please see the Working Group's implementation report.

Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the5 February 2004 W3C Patent Policy.W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes containsEssential Claim(s) must disclose the information in accordance withsection 6 of the W3C Patent Policy.

This document is governed by the 1 September 2015 W3C Process Document.

Table of Contents

1. 1. Introduction
2. 2. Conformance
3. 3. Performance Timeline
   1. 3.1 The PerformanceEntry interface
   2. 3.2 Extensions to the Performance interface
   3. 3.3 The PerformanceObserver interface
4. 4. Processing
   1. 4.1 Filter performance entry buffer by name and type
5. 5. Privacy and Security
6. A. Acknowledgments
7. B. References
   1. B.1 Normative references
   2. B.2 Informative references

1. Introduction

This section is non-normative.

Accurately measuring performance characteristics of web applications is an important aspect of making web applications faster. This specification defines the necessary Performance Timeline primitives that enable web developers to access, instrument, and retrieve various performance metrics from the full lifecycle of a web application.

[NAVIGATION-TIMING-2], [RESOURCE-TIMING], and [USER-TIMING] are examples of specifications that define timing information related to the navigation of the document, resources on the page, and developer scripts, respectively. Together these and other performance interfaces define performance metrics that describe the Performance Timeline of a web application. For example, the following script shows how a developer can access the Performance Timeline to obtain performance metrics related to the navigation of the document, resources on the page, and developer scripts:

Example 1

Alternatively, the developer can observe the Performance Timeline and be notified of new performance metrics via thePerformanceObserver interface:

Example 2