Say hello to frof

Inspired by the work I’d been doing with Benoit Girard to integrate the Firefox Profiler with Eideticker, I decided to create an easy-to-use python script to help with gathering profiles on Fennec, which I call frof.

Frof pretty considerably reduces the amount of busywork you need to do to gather a profile. Instead of a rather complicated multi-step process to initialize fennec with the right parameters for profiling, downloading profiles, etc., you can just run the frof script like so:

frof org.mozilla.fennec

Assuming that frof was bootstrapped correctly (and your phone is connected to your computer in debugging mode), this should start up fennec automatically with that URL loaded. Now, just perform whatever action you want to profile on your phone, then press enter in the terminal when you’re done. Voila, instant profile trace which you can examine, post to bugs, etc. All the other details are automated.

Backstory: the inspiration for frof came from a personal itch of mine, the fact that leaflet.js maps seem to be causing out-of-memory errors on Fennec when zooming is enabled (bug 784580). I wanted to be able to capture some profiles to see what was going on, but the current instructions on MDN seem a bit unwieldly. I figured I’d get lots of mileage out of a tool to make this easier (especially if I was going to get into a profile, edit, debug cycle), so I spent a few hours dilligently copying the logic we put into eideticker to gather profiles into a standalone script.

A profile I generated of a leaflet map with frof

Unfortunately in my case, the gecko profile didn’t tell me much, aside from the fact that Gecko didn’t seem to be the culprit (remember that on Android we also have lots of Java-based frontend code to contend with, which the profiler doesn’t measure). I’m going to stare more at the Java code and dig into the various high-level tools that Android provides for profiling performance and memory usage. My current hypothesis is that the problem is the screenshot code and the CSS transitions that leaflet generates when zooming. In the mean time, the only thing I have to show for my foray away from writing tools for Mozilla is … yet another tool.

Oh well, it could be worse. My fervent hope is that frof will be helpful for both Fennec developers and QA. Let me know if you wind up using it!

More Eideticker happenings: Profiling and startup testing

[ For more information on the Eideticker software I'm referring to, see this entry ]

Just wanted to give some updates on a few new Eideticker features which have landed in the past week.

Profiling support

While Eideticker is a great tool for observing the external behaviour of the mobile browser, it hasn’t been able to tell us much about what’s going on inside. If something’s slow, why is it slow? If it’s slower than it was the day before, what’s the cause? If it’s faster? What explains the deviations in test results from one run to the other?

Thanks to Benoit Girard (+ a little bit of integration work from me), we can now start providing answers to these questions. Eideticker now has a mode that allows us to capture a sampling profile of the application while the video capture is ongoing. From the dashboard, you can now get access said profile, just by clicking on a link.

Note that the profile is not yet synchronized precisely to the videocapture (the profile works over the entire run of the browser), but Benoit is busily making that happen. That should hopefully land soon, in the mean time we still have some pretty useful data.

To say I’m excited about this would be an understatement. I think it has the potential to open up a whole new world of understanding of why our mobile (and desktop, someday) browser performs the way it does.

Startup / pageload testing

Eideticker has had support for measuring startup and page load time for a few months now, but I hadn’t yet hooked it up to the dashboard. As of today, it now is. There’s a bunch of different angles that are interesting to measure here (new vs. old profiles, whether the browser has been launched since boot, launching web applications, loading about:home or loading a web page, …) which I’ll get to in due course. For now, we at least have a baseline of how long it takes to see the Firefox homescreen on a Galaxy Nexus:

Of course, this is hooked up to the profiling support previously mentioned. Here’s an example profile.

I’ve already filed one bug based on the data gathered so far. :)

Oh hai, I upergaded yer Eideticker

[ For more information on the Eideticker software I'm referring to, see this entry ]

More on this to come, but just a quick note that the client-side URL schema for the Eideticker dashboard has been changed, as we now gather benchmarks for more than one device (Samsung Galaxy Nexus benchmarks FTW). To get the new and improved dashboard, please just go to the root:

Old style URLs like will no longer work. Sorry for any broken links, this is the price of progress. ;)

Note that some benchmarks for the Galaxy Nexus are still missing. This is a known problem and will be fixed soon.