Actually, Chrome does process-per-domain. Almost always several tabs of the same domain will share a process. You can check this by killing one process and seeing lots of tabs go away.

No. We currently mostly do process-per-tab, but it gets complicated depending on how exactly a given window/tab was opened and certain resource heuristics. We're moving to process-per-origin[1], largely for the security improvement. But, that's been a huge, multi-year engineering effort that's only now approaching fruition.

[1] https://www.chromium.org/developers/design-documents/site-is...

I see.

So the reason more than one tab will crash when killing a process is that all those processes were sharing a resource of some sort?

Maybe the trick isn't to do process-per-tab or 1 content process and 1 UI process but to instead do some kind of "intelligent" number of content processes based on CPU and tab count? Like if you had 50 tabs on a quad core processor you could have 1 UI process and say five content processes?

Or another idea, have some kind of upper limit of memory a tab can use before it gets its own process.

That's likely what'll happen eventually. But we're starting with 1 content process because even that is a huge change and is going to cause disruption and will take a while to iron out the wrinkles.