Firefox and the JSS, high CPU usage

Honored Contributor

I've had an issue that's been rather frustrating in Firefox at least with the current major version 49. I wanted to see if others had seen it. I guess they introduced this new process separation for each tab in Firefox similar to what Chrome and Safari have done for a while and I've noticed that if I’ve got a lot of JSS tabs open, especially tabs where the session has timed out, it really brings the browser to a crawl. Activity monitor has the Firefox Web Content process beyond 100% CPU usage. Everything starts to calm down as soon as I close out the JSS tabs. Is anyone else seeing this in Firefox (or any other browser for that matter)? We are on JSS 9.93 if it makes a different, but the problem persists even with 9.96 which we've got setup in a test environment.


Contributor II

I've been seeing this behavior as well. I do most of my work in Firefox on my PC, where Firefox will slow down and eventually crash entirely, but I've noticed similar behavior when I do work on my mac. We are currently running on 9.96, but have been having these issues for a few versions.


I think it may have to do with the javascript they are using to track session expiration, but I've noticed recently that my FF uses a lot of CPU for no reason and I've seen memory bloat upwards of 5GB...

[about:performance](about:performance) may be helpful.

Contributor II

I left several tabs open, including one JSS tab and about:preformance, when I went to lunch. When I got back to my desk, the only tab that showed any performance hit was the JSS tab.

New Contributor

+1. I'm on JSS 9.96 and Firefox ESR 52 (though it's been happening for a while, so older versions of Firefox ESR can also be included) on Windows 7. If my Firefox is running slowly, I simply need to hunt down the tab which has a JSS tab open and once I close that, Firefox is back to its usual responsive self.

It's gotten worse than usual though, and I just tested and it took 14 seconds to load my policies.html page. Chrome does it in about 2.5 seconds. AdBlock Plus is running on Firefox.