Linux only recognising one cpu

emersony · 01-19-2007, 07:37 PM

Hi,

I have a Debian box with a 2.6 kernel compiled for SMP. Both cpus are being recognised by the bios at startup however /proc/cpuinfo only shows one cpu.

I really don't quite know where to start to figure out what is wrong here and googling is not very helpful.

If anyone can point me in the right direction I'd be eternally grateful. Or something like that.

thanks,

Emersony

osor · 01-19-2007, 09:05 PM

Are you positive the kernel is SMP-enabled (check the output of “uname -v”)?

xjlittle · 01-19-2007, 11:59 PM

Try looking at

Code:

dmesg |less

The top line should tell you if the kernel is smp

Code:

Linux version 2.6.9-42.0.3.ELsmp (brewbuilder@hs20-bc1-7.build.redhat.com) (gcc version 3.4.6 20060404 (Red Hat 3.4.6-3)) #1 SMP Mon Sep 25 17:28:02 EDT 2006

A little further down you should find a line that says

Code:

 Initializing CPU#0

and somewhat further down

Code:

 Initializing CPU#1

Of course you could just

Code:

dmesg |grep -i cpu

but then you wouldn't get to see all of the cool things in dmesg-some of which might tell what is wrong.

emersony · 02-19-2007, 05:28 PM

Thanks for the reply. It turned out that the installed SMP kernel wasn't the default kernel so I had to edit grub.

Unfortunately, neither the 2.6.8-2-686-SMP nor 2.6.8-3-686-SMP will boot.

2.6.8-2-686-SMP chokes on installation and then when booting can't di
as per this thread:
http://www.linuxquestions.org/questi...d.php?t=530490

2.6.8-3-686-SMP installed fine and starts to boot but then hangs up with this inode wierdness I'm still trying to solve:
http://www.linuxquestions.org/questi...d.php?t=530284

Those appear to be the only 2 SMP kernels for Sarge,,, wondering if I should try a more recent kernel from Etch or not.

Thanks again,

Emerson

emersony · 02-19-2007, 05:30 PM

Thanks for the reply. It turned out that the installed SMP kernel wasn't the default kernel so I had to edit grub.

Unfortunately, neither the 2.6.8-2-686-SMP nor 2.6.8-3-686-SMP will boot.

2.6.8-2-686-SMP chokes on installation and then when booting can't mount root fs on unknown block(0,0)
as per this thread:
http://www.linuxquestions.org/questi...d.php?t=530490

2.6.8-3-686-SMP installed fine and starts to boot but then hangs up with this inode wierdness I'm still trying to solve:
http://www.linuxquestions.org/questi...d.php?t=530284

Those appear to be the only two 2.6.8-SMP kernels for Sarge,,, wondering if I should try a more recent kernel from Etch or not.

Thanks again,

Emerson