smp kernel

[Chakravarthi]

Hi,

I have a Machine with Dual CPU, and the kernel which is built on the machine is smp kernel, using the same kernel i want to boot the machine with single cpu support, how this can be accomplished..

thanks
chakri

[Steven E. Protter]

The smp kernel works just fine on single cpu machines. I've tested this myself.

The grub interface has a kernel selection feature at boot time. Just pick it on the list after install.

The config file is called grub.conf and you can set the default numericly.

I have always done my kernel installs from up2date, thats how i get them.

SEP

[Mark Grant]

As usual, SEP is correct.

I just thought I'd clarify that you don't actually have to do anything at all. Not even change your boot loader config. Just remove the CPU and it will still work. Like SEP, I have done this myself.

[Stuart Browne]

If you want to physically remove a CPU, that's all fine.

However, I am unaware of a 'logical' way to remove a processor (i.e. to tell an SMP kernel to use only one of the two physical processors).

[Chakravarthi]

hi,

append="console=tty0 console=ttyS1,19200n8 maxcpus=1"

by adding above line in lilo.conf, i could boot with one cpu

[Chakravarthi]

Is there any way to debug the cpu errors,

i'm runnig REDHAT AD, on a PIII server with two processors, machine boots fine,, but when we give load to the machine , machine hangs,,, but with single cpu machine works fine..

[Martin P.J. Zinser]

Hello Chakri,

ok, now you tell us what the problem is ;-)

Can you give us the Redhat version and kernel
(uname -a) you are using. SMP is by no means trivial and things can go wrong. It might be that a kernel upgrade will proof helpful.

Greetings, Martin

[Mark Grant]

I used to get that on an old smp PIII. I never really pinned it down to anything in particular except it only ever seemed to happen when I had X running. As I had X running most of the time anyway, it wasn't a brilliantly useful deduction.

However, after a few kernel releases, download, compile, install, rinse & repeat the problem just went away. So I'd see if you can upgrade your kernel. Maybe upgrade X too

[Stuart Browne]

mm.. maxcpus=.. kewl.. will remember that one..

But yes, as Martin says, more details please!

[Chakravarthi]

Hi,

I'm using a PIII machine with Dual CPU, running Redhat Advanced Server

Red Hat Linux Advanced Server release 2.1AS (Pensacola)

kernel : kernel-2.4.9-e.3

the kernel was compiled for single CPU, so we enabled dual CPU option and recompiled the kernel,

the machine works fine as long as we dont run any processes, once the cpu loads goes up the machine hangs without giving any error, i have to had boot the machine, this can happen anytime, even i'm not able to get the messages on the monitor,


dont know where to start the debug process....
thanks
chakri