Mobile Firefox: Measuring how a browser feels(blog.mozilla.org)
blog.mozilla.org
Mobile Firefox: Measuring how a browser feels
http://blog.mozilla.org/futurereleases/2012/06/26/mobile-firefox-measuring-how-a-browser-feels/
4 comments
[deleted]
This is a really good step forward, but it's disappointing to see the author using FPS to measure UI responsiveness (I've harped on this before: http://news.ycombinator.com/item?id=3777058).
While FPS is a decent measure of performance in constant-load applications such as the fishbowl, it's really, really bad for sporadic-load applications such as most UIs.
For measuring UI responsiveness, you should really use frame delay, which is the greatest elapsed time between any two concurrent frames during a UI event. If your swipe gesture has a frame delay above ~33ms, it will look bad, even if your measured framerate is ~30fps.
While FPS is a decent measure of performance in constant-load applications such as the fishbowl, it's really, really bad for sporadic-load applications such as most UIs.
For measuring UI responsiveness, you should really use frame delay, which is the greatest elapsed time between any two concurrent frames during a UI event. If your swipe gesture has a frame delay above ~33ms, it will look bad, even if your measured framerate is ~30fps.
One of the big problems with frame delay is it tends to round up. On a 60FPS device 30.1FPS generally means you miss one out of every 2 refreshes. But a 35ms frame delay and you missed 2 refreshes and can even lose 3 which is ~100ms and rather noticeable.
True, but having 30.1FPS doesn't protect you from that phenomenon either. If you maintain 30.1FPS over a long period of time, it means that, yes, you generally get one out of every 2 refreshes.
The problem is that UI interaction events can take place over very short stretches -- say ~200ms. That's only a handful of frames, which reduces the quality of any metric that relies of averages (such as FPS). I don't really care if I get 1 out of every 2 refreshes as measured over 2 or 3 minutes, I care about the first 5 frames after I swipe the screen.
The problem is that UI interaction events can take place over very short stretches -- say ~200ms. That's only a handful of frames, which reduces the quality of any metric that relies of averages (such as FPS). I don't really care if I get 1 out of every 2 refreshes as measured over 2 or 3 minutes, I care about the first 5 frames after I swipe the screen.
I don't know if it's a good place to ask this question but what happend to Firefox for Android tablets? I hasn't been updated for some time. Can developers share any details about that?
According to http://arstechnica.com/gadgets/2012/06/hands-on-firefox-for-... it's still in active development but isn't yet feature-complete.
Right.
We currently don't support tablets in this release as development did not finish in time for this '1.0' style release. Fortunately, you can test out Nightly (our developer oriented release channel) which has some tablet-optimized changes available for download at http://nightly.mozilla.org [I'm a Mozilla QA Engineer]
We currently don't support tablets in this release as development did not finish in time for this '1.0' style release. Fortunately, you can test out Nightly (our developer oriented release channel) which has some tablet-optimized changes available for download at http://nightly.mozilla.org [I'm a Mozilla QA Engineer]
Let's hope they will do the same thing on Mac. Maybe they can get some tips from Camino team.
[1] https://air.mozilla.org/product-design-at-mozilla/