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Firefox To Get Multi-Process Browsing
An anonymous reader writes with news that multi-process browsing will be coming to Firefox. The project is called Electrolysis, and the developers "have already assembled a prototype that renders a page in a separate process from the interface shell in which it is displayed." Mozilla's Benjamin Smedberg says they're currently "[sprinting] as fast as possible to get basic code working, running simple testcase plugins and content tabs in a separate process," after which they'll fix everything that breaks in the process. Further details of their plan are available on the Mozilla wiki, and a summary is up at TechFragments.
What took so long?
Yeah! All they had to do was change their entire codebase from around 5+ years of Firefox (and probably more of Mozilla/Netscape) to update it! That's, what, half an hour's work? And don't give me this "legacy code" bullshit; if they bothered to anticipate our fifty bajillion core processors back then like any NORMAL person should today, they wouldn't be in this mess!
Lazy bastards. I mean, how hard is it to change what is apparently that one really trivial-to-find call in their code to useProcessSeparationOhAndIAlsoWantAPony(true)? Took them long enough...
Actually, they're talking about multiple processes, not multithreading. Threads all belong to a single process, which, if it crashes, will bring down all of its threads. Running the shell in one process, then each tab/window in its own process means that, much like Chrome, a single page can't bring down the myriad of tabs/windows you might have open, if you browse the web like I do.
-Matthew Riley "TofuMatt" MacPherson
I have a website
According to the Ars coverage:
It was probably too large a project to consider doing without a pressing need. Chrome and IE8 supplied that pressure.
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Really. And all this wouldn't even be a problem if they just wrote it in Java to begin with.
This is why we can't have nice things.
They had to chance a code base from around 5+ years only because they didn't things right 5+ years ago. Remember, back then they were doing a complete code rewrite anyway.
And no, the true reason to do this is not multicore. That it also gets faster on multicore is just a nice side effect. The true reason to do it is stability. If one page makes problems, you don't lose all the others. This was indeed even more important back when browser and mail was the same program, because it meant that a page crashing your browser could destroy your almost-completed email, too (yes, this has happened to me, although I'm not sure if it was still old Netscape or already new Mozilla). Of course, today it's quite possible that your browser is your mail client again because you're using webmail.
Note that if it were just a performance thing, they could have gone multithreaded instead. This would probably get even better performance.
The Tao of math: The numbers you can count are not the real numbers.
It was probably too large a project to consider doing without a pressing need.
Cuz yeah, Flash locking up the entire browser wasn't a pressing need until IE8 and Chrome. Riiiight.
LOTS of us have been asking about this for a VERY long time (years). Leaving it this late is called 'lack of vision'. This should've been in the very first version. Now there IS a ton of code to make this work with. I imagine that's why they call this Electrolysis...it's a hairy problem now that it's been ignored for so long.
Threading for Javascript? Not possible! Stop asking for something that can't be done! The Firefox devs cried!
Opposition to threading by Firefox devs came from, among others, Brendan Eich, the inventor of Javascript. You can read his well supported arguments on Bugzilla.
That doesn't excuse Firefox devs from not supporting a parallel architecture earlier, from which users would significantly benefit. But the conversation on that link is an oculus into the reasoning behind not having a parallel architecture earlier.
One way to implementing multi-process Firefox is first allow XPCOM to work across process. i.e. allow objects to be via XPCOM that are actually spawned in another process, one explicitly created for the task. In COM it had a thing called a running object table (ROT). When you create a process hosted object it looks to see if one is running already, and if not it uses the registry info to spawn one. Then it waits for it to start and then it tells the process to create the object, sets up all the marshaling etc. XPCOM could do something similar, though it would have to do so in a cross-platform manner. I assume that Firefox would have to determine when creating a browser object first if it was chrome or content, and if it was content to spawn a host process and then set up the interfaces. Once set up and assuming the interfaces were efficient, the effect would be largely transparent.
The biggest performance hit would probably be on anything which tried to call or iterate over the DOM boundary between chrome and content. For example chrome which introspected content would suffer because all the calls would have to be serialized / deserialized.
Personally I think its feasible but it would hit performance. An alternative would be to just host plugins in another process. Windowless plugins might be a pain to implement but at least you could kill the other process if a plugin goes nuts which seems to happen all too frequently for me.
Yes, they were. TraceMonkey was started in earnest in early summer 2008. Chrome was (accidentally) announced 1 September 2008.
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