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
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