JSMeter: Measuring JavaScript Web Applications

Established: March 2, 2010

JSMeter_logo_smThe goal of JSMeter is to measure the runtime behavior of JavaScript programs. Our ultimate goal is to improve the quality of JavaScript engine implementations.

Can you tell the JavaScript benchmark from the Real Web App?  


JavaScript is widely used in web-based applications and is increasing popular with developers. So-called ”browser wars” in recent years have focused on JavaScript performance, specifically claiming comparative results based on benchmark suites such as SunSpider and V8. In this paper we evaluate the behavior of JavaScript web applications from commercial websites and compare this behavior with the benchmarks.

We measure three specific areas of JavaScript runtime behavior: 1) functions and code; 2) heap-allocated objects and data; 3) events and handlers. We find that the benchmarks are not representative of many real websites and that conclusions reached from measuring the benchmarks may be misleading.

Specific examples of such misleading conclusions include the following: that web applications have many loops, that non-string objects in web applications are extremely short-lived, and that web applications handle few events.

We hope our results will convince the JavaScript community to develop and adopt benchmarks that are more representative of real web applications.

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Portrait of Ben Zorn

Ben Zorn

Partner Researcher