[GRLUG] 64-bit Linux

[Collin]

>
>
> Any x86-64 processor should have Intel's Paged Address Extensions,
> giving 32-bit operating systems access to up to (IIRC) 64GB of RAM.  I
> know it's possible on Linux, at the very least. See the "64GB high
> memory" option if you configure and compile your own kernel.
>
> I like x86-64 primarily because of the 8 GPRs that the compiler can
> optimize for, instead of 4 GPRs on IA32.  I've done enough performance
> coding to recognize how useful it can be to have that many more places
> to store values and pointers, and avoid needing to call out to cache.
>
>   

That's true. PAE has been available on a lot of intel processors for 
some time now. But, quite frankly, it sucks. The processor can't 
physically access all of that memory in one shot so you end with a lot 
of wrangling in page tables. It slows down the system performance. If 
you are going to slow down the performance anyway then you may as well 
go to 64 bit where sometimes it might actually be faster instead of slower.