Bug 968923 allows use counters for properties and methods. It would be good to have a way to track arbitrary things in the same way, by using Telemetry::Accumulate or equivalent. For instance, in bug 1295588, I wanted to track how many users hit pages that use particular inputs to methods, like document.createEvent("event"). A regular telemetry flag probe does work here, I think, but it doesn't get calculated the same way (percentage of page views).

Nathan, what do you think of this? Is this something we need or can this already be done with just adding new histograms?

(In reply to Nathan Froyd [:froydnj] from bug 1295588 comment #11) > (In reply to :Aryeh Gregor (working until September 2) from bug 1295588 comment #10) > > Nathan, is there any way to get "percentage of page views that hit this > > line" for things like this? Bug 968923 seems to have only intended to add > > statistics for access to a property or method, but I don't see whether > > there's a way to get the same data for something like this (percentage of > > page views that call a method with a given parameter). If there's no way to > > do it now, I'll file a bug. > > We don't have a way to do that.

I think we should do this with new histograms; wanting "arbitrary requirements" sounds like something better done at the C++ level and not in a structured thing like use counters. The extra histograms that you'd need to do something like this without use counters are histograms (e.g. a count of toplevel pages/total documents/chrome documents/etc.) we've been talking about adding to rework how use counters are done anyway...

(In reply to Nathan Froyd [:froydnj] from comment #3) > The extra histograms that you'd need > to do something like this without use counters are histograms (e.g. a count > of toplevel pages/total documents/chrome documents/etc.) we've been talking > about adding to rework how use counters are done anyway... Should we morph this to be about adding these foundational histograms and move this to some more appropriate component?

(In reply to Georg Fritzsche [:gfritzsche] from comment #4) > (In reply to Nathan Froyd [:froydnj] from comment #3) > > The extra histograms that you'd need > > to do something like this without use counters are histograms (e.g. a count > > of toplevel pages/total documents/chrome documents/etc.) we've been talking > > about adding to rework how use counters are done anyway... > > Should we morph this to be about adding these foundational histograms and > move this to some more appropriate component? That would be fine with me.