32bit efficiency under 64bit gentoo kernel?

[humbletech99]

Is it efficient to run 32-bit code under the 64-bit gentoo kernel?

I would think that there must be a level of emulation and therefore it is not as quick to run 32-bit under a 64-bit kernel as it would be to run it under a 32-bit kernel. But that's just my guess...

Somebody know their facts on this?
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[drwook]

I read the whitepapers out of AMD before deciding to go 64 bit, but that was a while ago now so the details have been pushed out of my neural FIFO buffer

Effectively, the performance isn't 100% of what you'd get in true native 32 bit mode, but it isn't far off (as in maybe 99%). It's hardware level rather than software emulation, and it's pretty much still native execution (some kind of switching delays IIRC, but they're negligible - it might or might not be emulation depending on your perspective, I think people have argued both sides).

Only negative is that in 64 bit mode the processor can't run 16 bit code like this (which it does in 32 bit mode, and probably every other 32 bit processor that evolved from a 16 bit one does that I know of - certainly anything x86). That said this is unlikely to affect many people - If it's going to, you probably know already

[humbletech99]

Ok, keeping my Gentoo64 it is! I will see how it goes...
_________________
The Human Equation:

value(geeks) > value(mundanes)