LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel
User Name
Password
Linux - Kernel This forum is for all discussion relating to the Linux kernel.

Notices


Reply
  Search this Thread
Old 08-14-2010, 05:41 AM   #1
nima0102
Member
 
Registered: Nov 2006
Posts: 209

Rep: Reputation: 30
Kernel not detect all core of cpu's


Hi
We have compiled kernel 2.6.30 from source code.But this kernel can not detect all core of cpu's.
on our system there are 2 cpu's and every cpu has 2 cores.but in /proc/cpuinfo there are 2 cpu's and every cpu has one core!!
I could not solve this problem yet.

Thanks for any help or guidance
 
Old 08-14-2010, 05:51 AM   #2
druuna
LQ Veteran
 
Registered: Sep 2003
Posts: 10,532
Blog Entries: 7

Rep: Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405
Hi,

You might want to set one or both of these options (if you haven't already):

Both to be found in: Processor type and features ->
- Symmetric multi-processing support
- SMT (Hyperthreading) scheduler support

Hope this helps.
 
Old 08-14-2010, 06:45 AM   #3
nima0102
Member
 
Registered: Nov 2006
Posts: 209

Original Poster
Rep: Reputation: 30
Quote:
Originally Posted by druuna View Post
Hi,

You might want to set one or both of these options (if you haven't already):

Both to be found in: Processor type and features ->
- Symmetric multi-processing support
- SMT (Hyperthreading) scheduler support

Hope this helps.
Thanks for your attention
I have checked those parameters,they are set!But my issue is not solved.

Thanks for more help or guidance
 
Old 08-14-2010, 07:12 AM   #4
druuna
LQ Veteran
 
Registered: Sep 2003
Posts: 10,532
Blog Entries: 7

Rep: Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405
Hi,

Other things I can come up with:

- Did you set the correct cpu (Processor family)
- Did you try setting mps tables (Enable MPS table)
- Did you change the Maximum number of CPU default (which is 8)

Maybe you can find a hint in the output of dmesg or /var/log/boot (or alike, if it exists).

And I do assume you rebooted after making the changes, recompiling and placing of the System.map and kernel image.

Hope this helps.
 
Old 08-15-2010, 05:43 AM   #5
nima0102
Member
 
Registered: Nov 2006
Posts: 209

Original Poster
Rep: Reputation: 30
Quote:
Originally Posted by druuna View Post
Hi,

Other things I can come up with:

- Did you set the correct cpu (Processor family)
- Did you try setting mps tables (Enable MPS table)
- Did you change the Maximum number of CPU default (which is 8)

Maybe you can find a hint in the output of dmesg or /var/log/boot (or alike, if it exists).

And I do assume you rebooted after making the changes, recompiling and placing of the System.map and kernel image.

Hope this helps.
Thanks for your reply.
I answer your questions in order you asked:

- CPU is E5502 xeon - Dual Core.
- I did not find such setting on kernel. target kernel is 2.6.30.9 - Official kernel.
- This option is default.

I have tried but without any luck.

Thanks for any help or guidance
 
Old 08-15-2010, 01:24 PM   #6
druuna
LQ Veteran
 
Registered: Sep 2003
Posts: 10,532
Blog Entries: 7

Rep: Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405Reputation: 2405
Hi,

I just downloaded 2.6.30.9 from kernel.org and checked for Enable MPS table: It is available under: Processor type and features -> Enable MPS table.

I do assume, looking at the CPU, that you have a X86_64 setup (BTW: the above setting is available with both x86 and x86_64).

You mention the cpu setting being: E5502 xeon - Dual Core. Do I assume correct that you choose Core 2/newer Xeon?
The E5502/Nehalem is not mentioned in the help part. Maybe you need to switch to Generic-x86-64

You haven't said if linux ran successfully before (with its default kernel). If that is the case, start that linux version and have a look at the output of /proc/cpuinfo to see if everything is ok, or if you still have missing cores.

You didn't say anything about checking the output of dmesg either. A lot of important info can be found there. The output of dmesg from your default linux (the one with the default kernel) can also be of great help, assuming that everything works ok.

Hope this helps.
 
Old 08-16-2010, 06:26 AM   #7
nima0102
Member
 
Registered: Nov 2006
Posts: 209

Original Poster
Rep: Reputation: 30
Thanks a lot for your attention.
After enabling ACPI in kernel, All cpu's correctly are displayed.
Anyhow thanks again.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
[SOLVED] Multiple core CPU's and Linux Josh000 Slackware 10 05-15-2010 07:38 AM
Mixing quad and dual core cpu's in the same machine sniff Linux - Hardware 12 09-26-2008 09:52 AM
Slackware 11 and shiny new dual core CPU's TL_CLD Slackware 8 01-02-2007 01:02 AM
Kernel version for different cpu's vatten Linux - Newbie 1 11-29-2006 02:17 PM
Dual Core CPU's - What Kernel carlosinfl Linux - Hardware 1 08-21-2006 01:55 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel

All times are GMT -5. The time now is 06:12 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration