User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0 Build ID: 20170623152303 Steps to reproduce: Closed a tab (Twitter on a hashtag). Actual results: Firefox suddenly took 100% CPU time (the fan started to make a lot of noise, and htop said that this was due to the firefox process). Expected results: Firefox should have still kept almost no CPU time. The about:performance page said that everything was performing well, with at most 1% CPU for each. So the permanent 100% CPU cannot be explained. Quitting and restarting Firefox solved the issue.
FYI: https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting_a_Performance_Problem This issue is reproducible?
No, the issue is not reproducible.
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0 Build ID: 20170809100326 I have tested your issue on latest Firefox release (54.0.1) and latest Nightly (Build ID: 20170809100326) and could not reproduce it. I have opened multiple Twitter tabs with # groups and close them one by one. Is this still reproducible on your end ? If yes, can you please retest this using latest Firefox release and latest Nightly build (https://nightly.mozilla.org/) and report back the results ? When doing this, please use a new clean Firefox profile, maybe even safe mode, to eliminate custom settings as a possible cause (https://goo.gl/AR5o9d).
(In reply to Vlad Bacia-Mociran [:VladB], Desktop Engineering QA from comment #3) > Is this still reproducible on your end ? No, I couldn't reproduce it yet.