Bug 137344 - Cannot disable hyperthreading on x86_64 platform
Cannot disable hyperthreading on x86_64 platform
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: kernel (Show other bugs)
3.0
x86_64 Linux
medium Severity medium
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Assigned To: Jim Paradis
Brian Brock
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Depends On:
Blocks: 168424
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Reported: 2004-10-27 13:27 EDT by David Lehman
Modified: 2013-08-05 21:09 EDT (History)
5 users (show)

See Also:
Fixed In Version: RHSA-2006-0144
Doc Type: Bug Fix
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Last Closed: 2006-03-15 10:44:25 EST
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RHEL 7.3 requirements from Atomic Host:
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Description David Lehman 2004-10-27 13:27:56 EDT
Description of problem:
x86_64 doesn't support disabling hyperthreading via the 'noht' kernel
option. This means that the only way to disable hyperthreading via
kernel arguments is with "acpi=off", which is known to break/disable
quite a few things and thus is not a viable alternative

Version-Release number of selected component (if applicable):
kernel-2.4.21-20.EL

How reproducible:
Always

Steps to Reproduce:
1. Boot x86_64 kernel with "noht" parameter
2. 
3.
  
Actual results:
Hyperthreading is still enabled

Expected results:
Hyperthreading is disabled

Additional info:
Comment 1 Jim Paradis 2004-10-29 01:17:49 EDT
*** Bug 137101 has been marked as a duplicate of this bug. ***
Comment 3 Jim Paradis 2004-12-03 12:26:57 EST
It should be pretty straightforward to duplicate what we do on the x86
side, modulo some differences in ACPI handling.  I see this as
perfectly doable in the U5 timeframe.
Comment 6 Eric Hagberg 2005-04-27 17:23:07 EDT
So it should be getting fixed in U5?
Comment 7 Jim Paradis 2005-04-27 17:52:22 EDT
No, this didn't make U5.  I'm testing the patch now that should be slated for U6.
Comment 16 Ernie Petrides 2005-10-20 01:42:12 EDT
A fix for this problem has just been committed to the RHEL3 U7
patch pool this evening (in kernel version 2.4.21-37.6.EL).
Comment 21 Red Hat Bugzilla 2006-03-15 10:44:25 EST
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2006-0144.html

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