1634507 - Record telemetry of WindowGlobalParents per Origin

Status: RESOLVED WONTFIX

(Core :: Performance: General, enhancement)

Description

[Beth Rennie [:beth] (she/her)]

We would like telemetry for how many BrowsingContextGroups exist within a process, which tells us in Fission how many different documents have loaded a single origin.

Comment 1

[Chris Peterson [:cpeterson]]

Barret, what decisions will we make using this telemetry?

IIUC, Nika says counting BrowsingContextGroups is a pretty indirect way of measuring the number of documents for a single origin and this probe would only be reported by the couple hundred users with Fission enabled.

Comment 2

[Beth Rennie [:beth] (she/her)]

We discussed this in #fission:mozilla.org and the metrics meeting last week. AIUI, we want this probe because it can give us insight into if users will be running a large amount of documents with the same origin, which could lead to slow downs for those origins since they will all be running in a single process in the fission case (versus being spread over multiple processes in the non-fission case).

Comment 3

[Beth Rennie [:beth] (she/her)]

Clarifying what exactly this is supposed to be measuring.

We were going to measure BCGs per process to get an idea of the number of tabs that had a document with a specific origin, but there are a few issues with that, namely that BCGs never go away once a process has been made aware of them.

Instead what we are going to do is measure the number of WindowGlobalParents per origin, which does not measure how many tabs have a specific origin loaded, but how many documents and subdocuments have a specific origin loaded.

Comment 4

[Chris Peterson [:cpeterson]]

Tracking for Fission Nightly milestone (M6a) because, IIUC, Barret will be working on this soon.

Comment 5

[Beth Rennie [:beth] (she/her)]

After discussing this offline, we're not sure how to proceed with collecting this telemetry. If someone really wants this, please re-open with a plan for how to collect it.