In IE8 and Chrome, Processes Are the New Threads

SenFo writes "To many of the people who downloaded Google Chrome last week, it was a surprise to observe that each opened tab runs in a separate process rather than a separate thread. Scott Hanselman, Lead Program Manager at Microsoft, discusses some of the benefits of running in separate processes as opposed to separate threads. A quote: 'Ah! But they're slow! They're slow to start up, and they are slow to communicate between, right? Well, kind of, not really anymore.'"

Comments

So...

[Anonymous Coward]

...his argument that processes aren't really slower than threads anymore is because your processor is faster?

Deja vu

[overshoot]

I remember the "processes vs. threads" argument, but last time around wasn't it Microsoft arguing that a threaded process model was superior to an isolated task model like Linux had? Weren't the Linux camp blowing the horn for the superior robustness and security of full task isolation?

My head hurts, I'm confused.

Re:Deja vu

[The Raven]

This is a misunderstanding of the application.

Microsoft said 'Threads are better than Processes for a web server', where you're wasting a ton of resources creating a new process for every CGI script that's run. They were right! Now every major web server supports in-process applications that are created once per server (perhaps with a pool of shared app space) rather than once per request.

Microsoft has never said that all the applications on your computer should run in one thread... that's just crazy talk.

This is simply a decision by Microsoft and Google to treat a browser tab as an application, rather than as a document. Now that web pages do a lot more processing (and crashing), this makes more sense than the old way. There's nothing particularly bad about using threads instead... Firefox is just fine with threads, I see no reason for them to undertake a massive change due to misplaced hype.

It really has to do with how much the processes share. If most of the memory per process could be shared, threads are probably more efficient. If not, processes. I'm no browser architect though, so I'll leave it up to Google, Mozilla, and Microsoft to make their own decisions.

Re:Processes

[ergo98]

Running each instance in a seperate process is NOT new technology

Well of course. It isn't even new in the browser world. In fact it's where we started.

The earliest browsers required you to run a new instance for each concurrently opened site. This presented onerous resource demands, so they made it more efficient by having multiple window instances run under one process, and then with tabs that obviously carried over to tabs running under one shared process.

This is so much ado about nothing. I can count on one hand the number of times I've had a problem with Firefox that would have been solved by it being in its own process.

Every bandwagoner, technical lightweight is now stomping their feet that Firefox needs to get on this yesterday, but really this is pretty low on the list of things that make a real improvement in people's lives. In fact I would go so far as to call it a gimmick. Presuming that the sandbox of a browser automatically stops sites from doing stupid stuff (unlike IE that will let a site kill just by going into a perpetual loop in JavaScript), and plug-ins are created by an idiot, this is completely unnecessary.

Chrome's great JavaScript is a real story, one upped by Firefox's ThreadMonkey doing one better. Those are real improvements that really do matter.

Cheap and Dirty Crash Isolation...

[nweaver]

The real reason for processes instead of threads is cheap & dirty crash isolation. Who cares about RPC time, you don't do THAT much of it in a web browser.

But with more and more apps being composed IN the browser, you need isolation to get at least some crash isolation between "apps"