topic Re: Bios showing two cpu in Operating System - Linux

Bios showing two cpu

K.C. Chan — Wed, 22 May 2002 14:15:59 GMT

All,
I've compiled my kernel with smp supports, but only one cpu is showing up in top, there's suppose to be according to the BIOS during boot. What gives? Shouldn't the kernel detected that there are 2 cpu on the system? Thanks.

Re: Bios showing two cpu

Stuart Browne — Wed, 22 May 2002 22:29:11 GMT

I don't suppose you'd care to tell us what hardware you're using?

Whilst he BIOS will state that there are two CPU's, it will also state whether a board is capable of having 2 CPU's.. Are you sure you arn't mis-interpreting what the bootup is saying?

Re: Bios showing two cpu

Jeffrey Wong — Wed, 22 May 2002 23:19:23 GMT

When you say that top shows only one processor, I assume you are referring top having a line labeled as CPU states. On some distributions, this line is a summary of what percentage of total cpu time was spent in each state, not a per cpu summary. To see if your system is using multiple processors, try 'cat /proc/stat'. If the kernel is using multiple processors, there should be a line in that file for each one.

Re: Bios showing two cpu

I_M — Thu, 23 May 2002 00:35:48 GMT

Hi

1) confirm you are using SMP kernel.
# dmesg

2) see your kernel recognize how many cpus.
# cat /proc/cpuinfo

If you see 2 cpus in cpuinfo,
find out which version of top you are using.
In your question, you didn't mention about your distribution.
If you are using Red Hat, top is in procps RPM.

# rpm -q procps

procps-2.0.6 show you only one line cpu usage. procps-2.0.7 support individual cpu usage.

Regards,

Re: Bios showing two cpu

K.C. Chan — Fri, 24 May 2002 14:02:27 GMT

All, attached is the output of cat /proc/stat and cat /proc/cpuinfo. From the output, the kernel does not seem to detect all the cpu.

Does it matter if I used i386 instead of i686 for the kernel, I am wondering about this because according to uname I have an i686.

For those who wish to know the type of HardWare and Flavor of Linux; I runing RH7.1 with 2.4.18 kernel (i386) with smp support. The box is a Compact Proliant.

Does any one have any idea why my kernel is only detecting 1 cpu whereas the BIOS tells me that there's 2 cpu? Thanks.

Re: Bios showing two cpu

Fabi — Fri, 24 May 2002 20:17:10 GMT

Is it possible to see the BIOS/POST messages?

Are you enabling CPU ID in the BIOS for both CPU's or only for one of them?

may i see your SMP options for your .config kernel file?

cheers!

Re: Bios showing two cpu

K.C. Chan — Tue, 28 May 2002 12:44:40 GMT

I can't post the Bios Message at the moment since I will have to reboot the box to get it. But here's the .config for the kernel.

Re: Bios showing two cpu

W. Michael King — Fri, 31 May 2002 18:55:12 GMT

Since we don't know the motherboard, here's something to consider.

From the SMP HowTO
http://www.tldp.org/HOWTO/SMP-HOWTO-3.html

...
A note from Richard Jelinek says also that activating the Enhanced RTC is necessary to get the second CPU working (identified) on some original Intel Mainboards.
...

Here's the steps:
make config # or menuconfig or xconfig
make dep
make clean
make bzImage # or whatever you want
# copy the kernel image manually then RUN LILO
# or make lilo
make modules
make modules_install

Good Luck!