User Agent: Mozilla/5.0 (Windows NT 6.3; rv:42.0) Gecko/20100101 Firefox/42.0 Build ID: 20150728030209 Steps to reproduce: On windows 7 Nightly 42.0a1 User Agent Mozilla/5.0 (Windows NT 6.1; rv:42.0) Gecko/20100101 Firefox/42.0 Build ID 20150728030209 1. Go to about:addons 2. Search for Lightbeam 3. Install Lightbeam (official add-on from mozilla) 4. Wait for a while Actual results: There was an error form nightly saying "Lightbeam might be making nightly run slowly" (see attachment) Expected results: There should be no error showing up as lightbeam is an official add-on from mozilla

Apparently it can be white-listed like in bug 1146380 comment 1.

I suspect that Lightbeam is using CPOW. Could someone point out to the line containing Lightbeam in about:performance?

Jank level, user, system and cross-process all of them have a value of 0 for lightbeam, but the activation field varies to different values. Tried on todays build, Still had no error what I had yesterday, anyway, there was a field saying "Slow add-ons alerts" which also had a value of 0, which indicates there is no error for slow add ons.

Ok, so that sounds good, I guess. "Activations" just shows how many time the add-on has executed any code, that doesn't trigger any alert.

I think this has been somehow fixed, but it showed this error each time I started nightly. Let me see for a few days, I will mark WFM then

It comes and goes, could not find any spesific reason of this message Dunno what happens at the back-end

I can reproduce the issue. This looks like the same issue as bug 1186379, so a mis-interaction between perf monitoring and jetpack.

This bug was filed to make a whitelist of mozilla's official add-ons like described in bug 1146380

My bad.

I thought lightbeam is an add-on that lets the user understand a lot about web privacy and the matter of sharing cookies between websites, which is pretty enough important. But the error message may discourage many users to use lightbeam, at least an official add-on does not deserve that like the Valence add-on is a necessary one for webIDE. So, I thought it is better to make a whitelist of mozilla's official add-ons and nightly to not show any erros, thus users will install official add-ons at least. Thanks for re-opening :) Let us know if that is possible for official add-ons

It should be possible. On the other hand, I prefer fixing the underlying issues, for the moment. Can you tell me whether the issue can still be reproduced?

Yes, but I am afraid it happens. in a random order, its hard to find exactly why and when it happens. Still let me know if there is any way to find. thanks

I also experience now this bug.

to_du: With which version of Nightly? As far as I can tell, all false alerts are now fixed, so this probably means that Lightbeam has performance issues. I may, of course, be wrong.

I use latest Firefox Nightly on Windows 10 x64. Bug: "Lightbeam might be making Nightly run slowly"

It;s Nightly x64.

Today this information has appeared again.

about:performance is being redesigned; mass closing the bugs related to parts of the current about:performance page that we are not keeping. Our goals with the redesign are to reduce the overhead caused by having the page opened, increase the reliability of the displayed information, and make the offered information actionable for most users. The back-end work is being tracked in bug 1419681.