Bug 665197

Summary: WARNING: APIC timer calibration may be wrong
Product: Red Hat Enterprise Linux 5 Reporter: Subhendu Ghosh <sghosh>
Component: kernelAssignee: Prarit Bhargava <prarit>
Status: CLOSED ERRATA QA Contact: Chao Ye <cye>
Severity: medium Docs Contact:
Priority: high    
Version: 5.4CC: akataria, caiqian, chyang, cye, czhang, dhoward, drjones, garrett, ghelleks, jsavanyo, jwilson, prarit
Target Milestone: rcKeywords: Regression, ZStream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Prior to this update, the following message was displayed when booting a Red Hat Enterprise Linux 5 system on a virtual guest: WARNING calibrate_APIC_clock: the APIC timer calibration may be wrong. This was due to the MAX_DIFFERENCE parameter value (in the APIC calibration loop) of 1000 cycles being too aggressive for virtual guests. APIC (Advanced Programmable Interrupt Controllers) and TSC (Time Stamp Counter) reads normally take longer than 1000 cycles when performed from inside a virtual guest, due to processors being scheduled away from and then back onto the guest. With this update, the MAX_DIFFERENCE parameter value has been increased to 10,000 for virtual guests.
Story Points: ---
Clone Of: 562006 Environment:
Last Closed: 2011-07-21 09:40:25 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 562006    
Bug Blocks: 680350    

Comment 5 Jarod Wilson 2011-03-03 20:33:56 UTC
in kernel-2.6.18-246.el5
You can download this test kernel (or newer) from http://people.redhat.com/jwilson/el5

Detailed testing feedback is always welcomed.

Comment 7 Martin Prpič 2011-04-14 10:17:03 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Prior to this update, the following message was displayed when booting a Red Hat Enterprise Linux 5 system on a virtual guest:

WARNING calibrate_APIC_clock: the APIC timer calibration may be wrong.

This was due to the MAX_DIFFERENCE parameter value (in the APIC calibration loop) of 1000 cycles being too aggressive for virtual guests. APIC (Advanced Programmable Interrupt Controllers) and TSC (Time Stamp Counter) reads normally take longer than 1000 cycles when performed from inside a virtual guest, due to processors being scheduled away from and then back onto the guest. With this update, the MAX_DIFFERENCE parameter value has been increased to 10,000 for virtual guests.

Comment 15 errata-xmlrpc 2011-07-21 09:40:25 UTC
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 therefore 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-2011-1065.html