On Monday 13 March 2006 12:31, Jim <[EMAIL PROTECTED]> wrote about 'Re: [gentoo-user] Mobo/proc combination': > Did you do AMD64 for gentoo or just x86? I just finished getting > everything compiled and setup where I like it. I won't mind doing it > again if running gentoo in 64-bit on an AMD64 would be a noticeable > difference from running 32-bit on an AMD64.
My recommendations are: <1G RAM : 32-bit kernel and userland <4G RAM : 64-bit kernel and 32-bit userland else : 64-bit kernel and 64-bit (multilib) userland Rationale: With less than 1G of ram you can still access all of it from any userland process without using the BIGMEM or HUGEMEM options [1]. You could gain a few extra registers from going 64-bit, but that probably doesn't make up for using twice the space for pointers and some other kernel structures. At /exactly/ 1G (or even really close, ~ >768M) you have to go BIGMEM or HUGEMEM to actually get use of all of that memory (in a 32-bit kernel), so I'd go with the 2nd option. With more than 1G but less than 4G you go 64-bit kernel to avoid the BIGMEM or HUGEMEM options, are let your 64-bit hardware to that work. 32-bit userland limits each process to only 4G addressable memory and denies userspace access to the 64-bit only registers, but you don't have 4G anyway and going 64-bit doubles the size of pointers in userspace. At /exactly/ 4G either the 2nd or 3rd option is tenable, but I'd go with the 3rd option is RAM is cheap and you'll probably add more later. Recompiling your entire userland is much more drastic that recompiling your kernel. Above 4G, you also really have a choice between option 2 and 3. I go with 3 because I believe that one process should be able to take all my physical memory if it needs it (and I don't ulimit it), particularly in the form of buffers and cache. I simply can't recommend going no-multilib right now. Perhaps in the future that will no longer be the case, but there's just too many things out there that you may want to install as 32-bit right now. -- "If there's one thing we've established over the years, it's that the vast majority of our users don't have the slightest clue what's best for them in terms of package stability." -- Gentoo Developer Ciaran McCreesh -- gentoo-user@gentoo.org mailing list
