1 or 2 processors? Depends upon which CD I boot

[BillS]

I am working on a Dell box with Knoppix 3.3 9/03 installed on the harddisk. 'cat /proc/cpuinfo' shows a single Intel P4 2.40 GHz. The same is true for the remastered CDs.
When I boot up (on the same box) the recent LocalAreaSecurity.com Knoppix based live CD, I get two Tuxs, and it finds 2 P4 2.40 GHZ processors.

Why? Is it in the SysLinux version? Any way to get to that other cpu?

This remastering can use all the cycles possible. Having the second processor might cut down in the making of the compressed ISO.

BillS

[EmDee]

'cat /proc/cpuinfo' shows a single Intel P4 2.40 GHz.true, P4s are not capable of multi processing, so there can only be one physical processor on your mobo.


When I boot up (on the same box) the recent LocalAreaSecurity.com Knoppix based live CD, I get two Tuxs, and it finds 2 P4 2.40 GHZ processors.Oops, how did you fit a second P4 in your machine?? Just kidding, to me it seems that you've got one of those P4s that have "hyperthreading"; that means that one physical processor behaves like two logical processors, see http://www-106.ibm.com/developerworks/linux/library/l-htl/!



Why? Is it in the SysLinux version? Any way to get to that other cpu? I don't think it has anything to with syslinux. LAS prolly has a smp (a.k.a. multiprocessing) enabled kernel, thats why! With knoppix you could try the "smp" boot option!

[windos_no_thanks]

LAS prolly has a smp (a.k.a. multiprocessing) enabled kernel, thats why! With knoppix you could try the "smp" boot option!
Knoppix should do smp by default, in fact on a double xeon machine at work I get four Tux when I boot up Knoppix without any cheat codes. :-)

[EmDee]

LAS prolly has a smp (a.k.a. multiprocessing) enabled kernel, thats why! With knoppix you could try the "smp" boot option!
Knoppix should do smp by default, in fact on a double xeon machine at work I get four Tux when I boot up Knoppix without any cheat codes. :-)Cool! So if you have some huge-ass server with, say, 24 CPUs, what'd ya see then? 24 tux??? <- I'd like too see a screenshot of that;-)

[BillS]

Just posting research results....
I think this is done in vmlinuz at the initial boot loader.

During the boot, it starts with
1) Syslinux banner line flashes on top of screen momentarily
2) Boot graphic and prompt (inside boot.img) are presented
3) options selected or not then <cr>
4) vmlinuz.........
5) miniroot.gz.........
6) screen clears
7) 1 or more Tuxs apear at top of screen
8) (that was an '8' paren) Some welcome string:
knoppix = Welcome to (multicolored) KNOPPIX Live-CD
L.A.S = Now booting Local Area Security 0.4.1
9) Found xxxx memory

At Step #8 we are at the first (almost) executable line of the 'linuxrc" script. This script is the only executable thing in the miniroot.gz, inside the boot.img.

The next action for linuxrc is to 'mount /dev/proc /proc". This is where the commandline and cpu information are taken from. The number of processors is already known, the comptessed file system with the kernel are not even looped and mounted yet.

The tailend of vmlinuz must be what loaded that '/dev/proc' structure just before clearing the screen and putting up the Tux and starting the linuxrc after opening miniroot.gz.

Also, the knoppix kernel is labeled as 2.4.22-xfs, and the L.A.S kernel is 2.4.20-xfs. The options configuration for Knoppix does set the only occurance of "xxx-SMP = y".

BillS