Created attachment 8782284 [details] Throbber shown instead of website Having e10s enabled, an unresponsive page in one tab breaks the display of all other tabs. Steps to reproduce: 1. Create a new Firefox profile 2. Go to https://www.mozilla.org/en-US/ 3. Open a new tab and go to https://ello.co/ddailey/post/hwqd8hmolnwx7-vp4zocfq  4. Switch back to the first tab => A throbber is shown instead of the website. I've tested this using 64-bit versions of Nightly 51.0a1 (2016-08-17) and Developer Edition 50.0a2 (2016-08-17) on Windows 7 SP1 64-bit. (With e10s disabled the website hangs the whole browser.) Sebastian  Got that link from https://lists.w3.org/Archives/Public/www-svg/2016Aug/0033.html
Note that the freeze is caused by an SVG image located at http://cs.sru.edu/~ddailey/svg/modifier3RBlendSnapMode.svg. While the freezing should be fixed in bug 1167471, freezing of a single tab should not have any influence on other tabs' contents. So I guess that will be solved with bug 1207306, right? Sebastian
I think this is basically just "no e10s-multi yet" in bug form, but I'll let mconley decide and dupe/close.
Yeah, in this case, the shared content process between all tabs is likely being bogged down with that SVG parse / render. e10s-multi will likely fix this. For cases where a website is doing something JS-heavy, we actually have a workaround for that in bug 1279086, where we'll interrupt the JS engine to prioritize painting, but I don't think that'll affect this particular case.