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Bug 305011 - [RHEL 5.1.z]: Tick divider bugs on x86_64
[RHEL 5.1.z]: Tick divider bugs on x86_64
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
urgent Severity medium
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Assigned To: Chris Lalancette
Martin Jenner
: ZStream
Depends On:
Blocks: 315471
  Show dependency treegraph
Reported: 2007-09-25 09:16 EDT by Chris Lalancette
Modified: 2009-07-20 05:59 EDT (History)
9 users (show)

See Also:
Fixed In Version: RHSA-2007-0993
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-11-29 09:46:55 EST
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Regression: ---
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Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
Patch to fix some of the tick divider problems (3.29 KB, patch)
2007-09-25 09:16 EDT, Chris Lalancette
no flags Details | Diff

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2007:0993 normal SHIPPED_LIVE Important: kernel security update 2007-11-29 09:46:49 EST

  None (edit)
Description Chris Lalancette 2007-09-25 09:16:34 EDT
Description of problem:
On x86_64, the tick divider patch seems to have multiple bugs, which cause
problems on VMware ESX server.  In particular, because not all of the clocks are
being properly divided, it needs many more interrupts than a kernel re-compiled
to 100HZ would, and can cause time drift.  The problems identified so far are:

1)  It does not set the local APIC to the "divided" value; it leaves it at the
undivided value.
2)  It does not properly account for lost ticks when using PM-timer (it thinks
there are more lost ticks than there actually are).
3)  It does not properly account for lost ticks when using TSC.

A preliminary patch (based on input from VMware) is attached.
Comment 1 Chris Lalancette 2007-09-25 09:16:35 EDT
Created attachment 205451 [details]
Patch to fix some of the tick divider problems
Comment 3 Alan Cox 2007-10-02 08:37:28 EDT
Looks sane on a first glance
Comment 4 RHEL Product and Program Management 2007-10-02 15:54:26 EDT
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
Comment 6 Anton Arapov 2007-10-24 16:54:57 EDT
A patch for this issue has been included in build 2.6.18-53.1.2
Comment 8 Mike Gahagan 2007-10-30 17:57:03 EDT
confirmed fix is in the -53.1.2 kernel, looks to have already been verified by
Comment 9 Mike Gahagan 2007-11-01 12:24:19 EDT
setting back to on_qa as this will go out to customers in a later erratum.
Comment 11 errata-xmlrpc 2007-11-29 09:46:55 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.


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