1569412 - Firefox 68 on wife's MacBook Air 2015 macOS 10.14.5 is getting dreadfully slow and no way to find out why

Status: NEW

(Core :: Performance: Responsiveness, enhancement, P3)

Description

[Peter Bengtsson [:peterbe]]

My wife is a Mozillian spouse and really wants Firefox to be her browser but her laptop becomes unbearable after some time, from using Firefox. She's switched to Google Chrome but tries to use Firefox for non-work browsing.

It's an older laptop and she has a fair amount of open tabs but no more than when she uses Chrome. It's not unusual that she gets that "Script is running slowly [Cancel] [Debug Script]" alert but either it happens when I'm not around (to see what "Debug Script" might say) or she's so upset with it that she has to restart the laptop.

Someone on #firefox Slack suggested looking at about:performance. But I have doubts. It just gives various snapshots and nothing's standing out. (See screenshots)
Someone also suggested the Gecko Profiler but I honestly don't know how to use that. I started, a profile, switched around the open tabs and published: https://perfht.ml/2GvH5t6
I suspect that's also just a snapshot of something.

What we need is a cumulative or aggregate of about:performance that can deduce, say of the last 30 days, which URLs or add-ons that are constantly causing excess "Energy Impact". Or, whenever a URL or domain spikes in absurd CPU or memory usage that that tally in some aggregate.

This is an opportunity to really make Firefox Release performant and measurable on older hardware. It's not my laptop but I can help Firefox Performance engineers answer questions.

Comment 1

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2019-07-27 at 10.46.06 AM.png

about:performance snapshot 1

Comment 2

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2019-07-27 at 10.31.14 AM.png

about:performance snapshot 2

Comment 3

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2019-07-27 at 10.28.57 AM.png

about:performance snapshot 3

Comment 4

[Peter Bengtsson [:peterbe]]

I looked in about:crashes. None since January 2019. That's 6 months ago.

Anything else I should look look for in the great forest of about:telemetry?

Comment 5

[Peter Bengtsson [:peterbe]]

For what it's worth, when I restarted her Firefox, the very bottom chrome footer there was a message about "Seems your Firefox is slow... to... start..." (or something like that) and it linked to https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings?redirectlocale=en-US&redirectslug=reset-firefox-easily-fix-most-problems

We could try that but I think we should explore if there are other toolings we can do first to make things more measurable and profiled first.

Comment 6

[Jean Gong :jgong]

Can you provide more specific detail on what effect appears to be slow. It's still unclear what parts are slow for the issue you are encountering.

Comment 7

[Peter Bengtsson [:peterbe]]

(In reply to Jean Gong :jgong from comment #6)

Can you provide more specific detail on what effect appears to be slow. It's still unclear what parts are slow for the issue you are encountering.

I can't. It's not that easy.

What's going on is that there's something that happens sometimes that's slowing it down to a crawl. It's a slow and old laptop which probably helps to highlight the flaws.

What's needed is something like about:performance but over time. Ideally a storage of what extensions or URLs that cause serious spikes. Like New Relic can do for server metrics. New Relic also has a very interesting and inspiring feature which is "Most time consuming" transactions. You select a time interval, e.g. last 12h, and it will show you which functions have the highest frequency x time.

Who knows, it could be the Adblock. Or mail.google.com. Or youtube.com. Or SomeRogueThemeAddon. It might not be slow right here right now this instant but sometimes it might spiking CPU or spiking memory like crazy. Where can I find that out?