[Webkit-unassigned] [Bug 105513] Add a performance test for Accelerated Compositing.

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=105513


Simon Fraser (smfr) <simon.fraser at apple.com> changed:

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--- Comment #8 from Simon Fraser (smfr) <simon.fraser at apple.com>  2013-01-02 20:52:34 PST ---
(From update of attachment 180313)
View in context: https://bugs.webkit.org/attachment.cgi?id=180313&action=review

> PerformanceTests/Animation/resources/leaves.js:178
> +window.onload = function () {
> +    PerfTestRunner.prepareToMeasureValuesAsync({iterationCount: 10, done: onCompletedRun, unit: 'fps'});
> +    window.webkitRequestAnimationFrame(onAnimationFrame);
> +}

window.addEventListener('load', ...) is better style.

> PerformanceTests/Animation/resources/leaves.js:201
> +function onAnimationFrame() {
> +    if ((iteration++ % FRAMES_PER_TIMER_READING) == 0) {
> +        var currTime = new Date();
> +
> +        // Calculate the framerate based upon the difference between the absolute times of the oldest and newest frames, subdivided by how macany frames were drawn inbetween
> +        var frameRateVal = (FRAMES_PER_TIMER_READING * 1000) / (currTime - lastMeasuredTime);
> +        if (!isNaN(frameRateVal))
> +            PerfTestRunner.measureValueAsync(frameRateVal);
> +
> +        lastMeasuredTime = currTime;
> +    }
> +    if (!measureCompleted) {
> +        window.webkitRequestAnimationFrame(onAnimationFrame);
> +    }
> +}

You're assuming that RAF frequency is related to the frequency with which CSS animations are rendered. This is not true on some platforms, so I don't think this is really a useful way to measure CSS animation performance.

There are other interesting things to measure: how fast this animations runs when driven via RAF, or how expensive it is to do layout on a page with lots of accelerated compositing layers. But I don't think this test useful for all platforms.

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