[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Finalize install questions



On Sun, 2004-12-05 at 14:37 +0100, Jan-Benedict Glaw wrote:
> On Sat, 2004-12-04 23:29:48 -0700, Robert LeBlanc <robert@leblancnet.us>
> wrote in message <[🔎] 8C7BA7940746324BA6DFF77AAC3A4D6077A7@q.LeBlancNet.us>:
> > First, a program needs to be specifically written for 64 bits? Or by
> > just recompiling using 64-bit libs usually good enough?
> 
> A program needs to be *cleanly* written to compile on a 64 bit system.
> However, that's not usually the case, especially if the program was
> never ever tested on anything but i386.
> 
> Also, not all programs run faster because of being compiled to 64 bit
> programs; to be honest, I expect that most programs would better stay in
> 32 bit because of memory size.

We'll never know, I guess, since x86-64 isn't *just* AthlonXP extended
by 32 bits.

> If you *really* want to take advantage of the 64 bit Opteron, you should
> have an eye on the code GCC generates. At some time, it may be better to
> code core routines (for mathematical computing) in assembler or to use
> existing libraries that do exactly this...

Currently, apps like mplayer and OpenSSL run much faster on x86-32
because such core routines are in hand-coded assembler.

For most other things, though, GCC 3.4 uses the extra 8 registers
to good effect.

> > Second, to install a 64-bit kernel, you have to be running a 64-bit
> > kernel using deb packages?
> 
> No. 64 bit userspace needs a 64 bit kernel, but all other combinations
> have no further dependancies.
> 
> MfG, JBG
> 

-- 
-----------------------------------------------------------------
Ron Johnson, Jr.
Jefferson, LA USA
PGP Key ID 8834C06B I prefer encrypted mail.

"He that would live in peace and at ease must not speak all he
knows or all he sees."
Benjamin Franklin

Attachment: signature.asc
Description: This is a digitally signed message part


Reply to: