We spend several ms at startup constructing exception objects for startupRecorder.js ahen it checks for uninstantiated services. This isn't an issue for release builds, but it does add extra overhead and GC pressure for nightly talos runs, and ordinary nightly users, that we wouldn't see on release. Which means it gives us a bad picture of what's going on for normal users.

Comment on attachment 8896658 [details] Bug 1389848: Make isServiceInstantiated*() return false rather than throw for uninstantiated services. https://reviewboard.mozilla.org/r/167952/#review173466

Pushed by maglione.k@gmail.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/e19453003208 Make isServiceInstantiated*() return false rather than throw for uninstantiated services. r=ehsan

https://hg.mozilla.org/integration/mozilla-inbound/rev/1952f907b15b7e5a508f8b35c3b63089d949de0d Bug 1389848: Follow-up: Bustage fix.

https://hg.mozilla.org/mozilla-central/rev/e19453003208 https://hg.mozilla.org/mozilla-central/rev/1952f907b15b

If we wanted to completely avoid the startupRecorder overhead related to listing services, we should add a native method returning the list of already instantiated services, instead of having JS code iterating through all the registered contract ids. I didn't bother doing it at the time because it was nightly-only code. But thanks for improving it :-)