Multiprocess isn't some magical panacea, its use is essentially to contain buggy code which shouldn't exist in the first place (this is true for its use as introducing extra security context for page content as well as its improvements to robustness against hangs). In both instances, a safer implementation language, or moving rendering and JS interpretation off the UI thread could be said to be far more elegant solutions. Mozilla is about a decade ahead of the curve here, with Rust and Servo providing both.
This. I am a SW tester and regularly use all the major browsers. I frankly do not see any lack in the current non-multiprocess FF in terms of the majority of browsing scenarios. If you really want the browser to be the operating system multi-processing is important, but for those not as interested in Google's agenda it isn't nearly as pertinent.
(I'm a program manager on Mozilla's video team, so I'm definitely interested in your YouTube problems. :) YouTube playback is common user complaint, but it can be very configuration dependent.)
When you say the browser freezes, is it permanently deadlocked or does the video eventually start playing? Firefox 38 on Linux does not support MSE (Media Source Extensions), so YouTube's HTML5 video player can't use adaptive streaming. YouTube is blocked on Firefox's download and rate estimation of the video. It sounds like the YouTube player or Firefox might be stuck in a busy loop downloading the video.
To test whether the video download is causing the problem, you could try flipping the "media.mediasource.enabled" to about:config pref to true and "media.mediasource.whitelist" about:config pref to false (and restarting Firefox) to see if MSE helps. Alternately, MSE is enabled on Linux in Firefox Nightly (41) and Dev Edition (40) so you could just try them.
Does Flash play without freezing, if you have Flash installed? Flash on Linux supports H.264, but Firefox only supports VP8, VP9, and WebM unless you have gstreamer's H.264 decoder installed (but it has its own problems).
Nope, it starts playing after a bit. I'm afraid I won't be at my desktop, where this is more egregious, for about a week, but I'll investigate and reply again when I'm back. It does sound like the problem is what you describe, although I think I'm running Aurora on the desktop.
Buggy code shouldn't exist. Buggy code exists. When the buggy code in question isn't written by the browser then it's up to the browser to properly deal with that buggy code. Firefox doesn't. Other browsers do, but Firefox doesn't. Thus as a user I can either use Firefox and have a bad time or not use Firefox and have a good time. The choice is easy.
Maybe Mozilla is planning for the future better than all others. Perhaps in another 10 years Firefox won't be a shitty user experience. I will gladly switch if that becomes the case. I'm not holding my breath.
It's not that it's a full decade behind the curve, it's a decade behind where your perceived curve. There are advantages and disadvantages to both monolithic kernel and microkernel operating systems^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H browsers.
