Tab closing became very slow in today's nightly

[past]

I've been using containers for quite some time, but I noticed after today's update that my nightly was very slow to close a tab when containers was enabled. This happened on my main profile in both windows and macOS.

Here is a profile: https://perfht.ml/2rzd7Pf

mconley and florian suggested that sending telemetry is what is causing this. sendTelemetryPayload from resource://testpilot-containers/index.js may be triggering bug 1369594.

Could be related to mozilla/testpilot#2422.

[mikeconley]

Filed by a separate user here: https://bugzilla.mozilla.org/show_bug.cgi?id=1373822

[jonathanKingston]

Hey @groovecoder the sendTelemetryPayload method goes straight to sending the call right? I wonder if using a message queue style setup to send the events on shutdown and when the browser is idle?

Should shared workers be investigated for preventing telemetry blocking the main code?

[kjozwiak]

Here's another profile that was added in bug#1373822 which demonstrates the performance regression.

[grahamperrin]

Please: with release 56.0 of Firefox, is this still an issue?

If it helps: Mozilla bug 1373822 - Lag when closing tabs is RESOLVED INVALID.

[past]

Well that bug was closed as invalid, because this issue was the place where we would track the problem. That being said, I haven't experienced this issue again in the last few months.

[groovecoder]

Closing unless/until we can reproduce.