Bug 113592

Summary: Hyperthreading does not show additional processors on PC-DL motherboard
Product: [Retired] Red Hat Linux Reporter: Giorel <grosario>
Component: kernelAssignee: Dave Jones <davej>
Status: CLOSED WONTFIX QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 9CC: pfrields, riel
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2004-07-12 21:02:26 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
sysreport bzip, should include dmesg entry none

Description Giorel 2004-01-15 17:12:21 UTC 
From Bugzilla Helper:
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Description of problem:
cat /proc/cpuinfo

only shows cpu0 and cpu1 when on smp
only shows cpu0 when not on smp

But this is dual xeon machine, and bootup says hyperthreading is enabled.

Tried noapic parameter...no effect

This is the motherboard:
http://usa.asus.com/products/server/srv-mb/pc-dl/overview.HTM

no noht passed in kernel or /etc/grub.conf, ht just regular flag on
cpuinfo, everything in BIOS shows HT is enabled.

First it was 2.4.20-6smp, but now
2.4.20-24.9smp doesn't show improvement.

Realize errata for 9 will cease in April, but if it isn't too late
really like a possible fix.  Hasn't been tried on Enterprise 3?

Version-Release number of selected component (if applicable):
kernel-2.4.20-24.9smp

How reproducible:
Always

Steps to Reproduce:
1. enable Hyperthreading in BIOS
2. boot up into any linux 9 kernel
3. cat /proc/cpuinfo
    

Actual Results:  In non SMP kernel:  1 processor
In SMP kernel:  2 processors

Expected Results:  In non SMP kernel:  2 processor
In SMP kernel:  4 processors

Additional info:

Customer opened support case number 139877 with ASUS.
Comment 1 Dave Jones 2004-01-15 17:35:11 UTC 
The non-SMP kernel will only ever show 1 processor.
Comment 3 Dave Jones 2004-01-15 17:40:32 UTC 
duh, brain not in gear. I missed the fact that the SMP kernel was
missing the HT pairs. Hmm. Can we get dmesg output of the SMP kernel ?
Comment 4 Giorel 2004-01-16 16:38:03 UTC 
Created attachment 97058 [details]
sysreport bzip, should include dmesg entry

sysreport
Comment 5 Giorel 2004-01-16 16:39:37 UTC 
please right click, file was supposed to be sysreport.bz2
Comment 6 Dave Jones 2004-07-12 21:02:26 UTC 
end-of-life'd product