I am trying to understand the performance overhead of iframes in their various forms however the information on this topic is particularly difficult to obtain. I am not sure where to even look in Chrome to find data on this.
In general, a new tab in Chrome is sandboxed from every other tab and as such they represent 1T units of memory.
A same-origin iframe shares the memory of the host page and thus I would assume it consumes little-to-no additional memory - say 0.1T worth of memory.
However cross origin iframes are sandboxed and as such they do not have access to the host page's memory (and they are potentially running in their own thread, though this is unclear). Does that mean a cross origin iframe has the same memory footprint of opening a whole Chrome tab (+1T)?
How does this apply to multiple iframes? Is it a case where the first cross origin iframe is +1T, but subsequent iframes on the same domain are +0.1T?
My speculation is something like this:
T = Memory usage of 1 Chrome Tab
| Memory Usage X | Same Origin | Cross Origin |
|---|---|---|
| One Iframe | +0.1T | +1T |
| Multiple Iframes | First +0.1T, Subsequent +0.1T | First +1T, Subsequent +0.1T |
I don't know how to check this is true. Where can one inspect the granular memory usage details of a page in Chrome?
Does anyone have insight into this?