Re: Speaking of PAE

[Martin Husemann <martin%duskware.de@localhost>]

On Fri, Jan 29, 2016 at 02:09:17PM -0700, Swift Griggs wrote:
> 
> Can any of the kernel gods comment on if PAE is still considered unstable? 
> It's hard to tell if it's disabled by default because it conflicts with 
> the Xen memory model, or if it's because it causes stability issues.

Not unstable (AFAICT), but it comes with a performance penalty.

In some environments it makes sense (e.g. a i386 xen domU on a 64bit
setup and little virtual memory allocated - I'm running one of those
myself), but in most cases a straight i386 kernel (for max 4GB
installed) or a straight amd64 kernel otherwise are preferable.

But if you go with a amd64 kernel, you still can install i386 userland
and have all the same benefits you get with i386-pae. Modulo bugs in the
compat_netbsd32 emulation the userland side of things should be the same.

There are a few minor issues (e.g. i386 savecore can not deal with a amd64
kernel crash dump). We use this type of setup as default on mips64 and
are trying to minimize the fallout.

Martin