Categories
Mozilla

Startup Time in the Wild

Over the weekend I spent some serious time with my computer running a bunch of tests with standalone talos in 11 different situations. First, a disclaimer: these tests were only designed to give some insight on the areas we should focus on for the goal. Each of these tests was reproduced at least once before I moved onto the next one in order to make sure the numbers were stable.

The Tests

  • Clean profile. This is just the standard profile that we normally run Ts with on tinderbox. This is basically used a baseline for best possible performance.
  • Dirty profile. This is actually my daily profile, with eight tabs that will open through session restore during startup. Because of how talos works, these tabs don’t all have to load for the number to be generated. Even so, you’ll notice a substantial slowdown. Sadly, I fear I modified the profile I was using in a bad way because I can no longer reproduce the numbers I got (but the numbers recorded were reproduced four times before I moved on to the rest of the tests initially).
  • Bookmarks toolbar disabled. This is a variation on the dirty profile test that just disables the bookmarks toolbar.
  • No places. This is a variation on the dirty profile test that removes places files from the profile.
  • No sessionstore.js. This is a variation on the dirty profile test that removes sessionstore.js from the profile. This has the side effect of also not making the eight tabs load at startup.
  • No urlclassifier. This is a variation on the dirty profile test that removes the urlclassifier related files from the profile.
  • No cookies.sqlite. This is a variation on the dirty profile test that removes cookies.sqlite from the profile.
  • No extensions. This is a variation on the dirty profile test that removes all add-on manager bits in the profile.
  • No formhistory.sqlite. This is a variation on the dirty profile test that removes formhistory.sqlite from the profile.
  • No downloads.sqlite. This is a variation on the dirty profile test that removes downloads.sqlite from the profile.
  • No content-prefs.sqlite. This is a variation on the ditry profile test that removes content-prefs.sqlite from the profile.

Results

I’m going to let some graphs do the talking here. The first shows the raw test run data (which isn’t terribly interesting). The second compares the reported startup time for each test. You will probably want to click to zoom in.

Data of the startup time runs

Startup time of the various tests

Conclusions

It looks like the best wins that we can get are related to fixing session restore to not scale linearly with the number of tabs it is restoring, and reduce the startup time costs of loading places files and cookies.sqlite. It should be noted that this test was not measuring the load time for each tab, so something like BarTab would not help in this case. The other good news is that we already have work underway to make cookies.sqlite load time not hurt us so much during startup.

Categories
Mozilla

Better SQLite Memory Reporting Coming to a Nightly Near You

I just landed bug 575667 into mozilla-central which adds more detailed reporting about the memory used by SQLite. Some people have been complaining to me that SQLite is using an awful lot of memory lately. My hunch was that most of this was the page cache (so you don’t have to hit the disk for every read), but with the next nightly those people can see for themselves. Now, instead of just indicating how much memory is being used, about:memory states how much is being used by the page cache and how much other memory is being used by SQLite. We are also planning to split this up more, but are waiting for the SQLite team to provide some APIs first.

Categories
Mozilla

New DOM Inspector Peers

Today, I’ve officially made Neil Rashbrook and Colby Russel peers for DOM Inspector code. If you have a patch you’d like to get reviewed for it, you can now ask either one of them to review it in addition to me now.

Happy patching!

Categories
Mozilla

Bugzilla Helper 0.4.1 Released

You can get it over at AMO. This version includes the integration of Thunzilla, an add-on originally created by Justin Dolske. I also made some minor improvements on the detection algorithm for what e-mails you can reply to.

Categories
Mozilla

Did you know we have a style guide?

I’ve been surprised at the number of people who were unaware that Mozilla has a coding style guide. It contains the rules for new files for both JavaScript and C++. You can save your reviewer a whole bunch of time by making sure your code conforms to this before asking for review.