[dundee] Linux on the desktop

[Jonathan Barber]

On Tue, Jan 13, 2004 at 04:09:18PM +0000, Andrew Clayton wrote:
> On Tue, 2004-01-13 at 15:09, Jonathan Barber wrote:
> [snip]
> 
> > > Bigger binaries and can have slower performance.
> > 
> > WRT performance, are you refering to running binaries compiled for 32bit
> > x86 platforms on 64bit platforms, or is this something else.
> > 
> 
> No. You can't easily take a 32bit ELF Linux/x86 binary and run it on a 
> Linux/Sparc64 for example...

I thought you might be talking about running 32 bit x86 apps under
emulation on Opteron/Itanium.

> What I'm meaning is, using, Linux/Sparc64 for example. The kernel is
> 64bit, userland is 32bit. If you compile stuff as 64bit then the
> binaries will be bigger and will likely run slower than their 32bit
> brothers. 
> 
> Basically, IMHO, if you (anyone in general) think going to 64bits is
> suddenly going to make everything faster, then you are going to be
> dissapointed. Generally the main reason for using 64bit's is for
> accessing large amounts of memory (where large may be >4GB). Or when
> doing BIG science and using 64bit values is a help.

I do big science, and the 4Gb limit is a PITA. As I understood it, the
unique selling point that AMD and Intel are putting forward for home
users is that you can have much more realistic graphics in games...

> For the average home user, they aren't going to see much benefit.
>  
> Hmm. A quick check on a Solaris 7/SPARC64 system shows that the general
> userland is only 32bit.

I googled on this, Solaris 8 does, but the userland programs are by
default 32bit. To get 64 bit use the -m64 flag with gcc.

jon at hornet:~$ cat test.c
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char **argv) {
    printf("hello world\n");
    return EXIT_SUCCESS;
}
jon at hornet:~$ gcc -m64 test.c
jon at hornet:~$ file ~/a.out
/homes/jon/a.out:       ELF 64-bit MSB executable SPARCV9 Version 1,
dynamically linked, not stripped 

> (pts/1) [andrew at rts:~]$ file /bin/ls
> /bin/ls:        ELF 32-bit MSB executable SPARC Version 1, dynamically
> linked, stripped
> (pts/1) [andrew at rts:~]$
> 
> 
> If you have a 64bit system and can run 32bit binaries, then your
> probably better off doing so. If not I wouldn't loose any sleep over
> it.. ;)
> 
> > Do you have any links handy?
> > 
> 
> Sorry no handy links... just what I've read and learnt in posts from the
> likes of Ben Collins (Debian SPARC maintainer) and Dave Miller (SPARC
> and Networking maintainer, Linux Kernel).
-- 
Jon