All Aboard the Release Train!

I’m working on a dashboard (a word which here means a website that has plots on it) to show Firefox crashes per channel over time. The idea is to create a resource for Release Management to figure out if there’s something wrong with a given version of Firefox with enough lead time to then do something about it.

It’s entering its final form (awaiting further feedback from relman and others to polish it) and while poking around (let’s call it “testing”) I noticed a pattern:auroramcscrashes

Each one of those spikes happens on a “merge day” when the Aurora channel (the channel powering Firefox Developer Edition) updates to the latest code from the Nightly channel (the channel powering Firefox Nightly). From then on, only stabilizing changes are merged so that when the next merge day comes, we have a nice, stable build to promote from Aurora to the Beta channel (the channel powering Firefox Beta). Beta undergoes further stabilization on a slower schedule (a new build every week or two instead of daily) to become a candidate for the Release channel (which powers Firefox).

For what it’s worth, this is called the Train Model. It allows us to ship stable and secure code with the latest features every six-to-eight weeks to hundreds of millions of users. It’s pretty neat.

And what that picture up there shows is that it works. The improvement is especially noticeable on the Aurora branch where we go from crashing 9-10 times for every thousand hours of use to 3-4 times for every thousand hours.

Now, the number and diversity of users on the Aurora branch is limited, so when the code rides the trains to Beta, the crash rate goes up. Suddenly code that seemed stable across the Aurora userbase is exposed to previously-unseen usage patterns and configurations of hardware and software and addons. This is one of the reasons why our pre-release users are so precious to us: they provide us with the early warnings we need to stabilize our code for the wild diversity of our users as well as the wild diversity of the Web.

If you’d like to poke around at the dashboard yourself, it’s over here. Eventually it’ll get merged into when it’s been reviewed and formalized.

If you have any brilliant ideas of how to improve it, or find any mistakes or bugs, please comment on the tracking bug where the discussion is currently ongoing.

If you’d like to help in an different way, consider installing Firefox Beta. It should look and act almost exactly like your current Firefox, but with some pre-release goodies that you get to use before anyone else (like how Firefox Beta 50 lets you use Reader Mode when you want to print a web page to skip all the unnecessary sidebars and ads). By doing this you are helping us ship the best Firefox we can.



One thought on “All Aboard the Release Train!

  1. Pingback: Data Science is Hard – Case Study: Latency of Firefox Crash Rates – chuttenblog

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