Bug 690134

Summary:	Time runs too fast in a VM on processors with > 4GHZ freq [rhel-5.6.z]
Product:	Red Hat Enterprise Linux 5	Reporter:	RHEL Program Management <pm-rhel>
Component:	kernel	Assignee:	Zachary Amsden <zamsden>
Status:	CLOSED ERRATA	QA Contact:	Red Hat Kernel QE team <kernel-qe>
Severity:	high	Docs Contact:
Priority:	urgent
Version:	5.7	CC:	akataria, dhecht, dhoward, garrett, jpirko, jsavanyo, knoel, mjenner, plougher, plyons, pm-eus, prarit, qcai, sghosh, tburke, yugzhang, zamsden
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.18-238.10.1.el5	Doc Type:	Bug Fix
Doc Text:	Previously, on VMware, the time ran too fast on virtual machines with more than 4GHz TSC (Time Step Counter) processor frequency if they were using PIT/TSC based timekeeping. This was due to a calculation bug in the get_hypervisor_cycles_per_sec function. This update fixes the calculation, and timekeeping works correctly for such virtual machines	Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-05-31 14:08:52 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	673242
Bug Blocks:

Description RHEL Program Management 2011-03-23 12:14:26 UTC

This bug has been copied from bug #673242 and has been proposed
to be backported to 5.6 z-stream (EUS).

Comment 3 Phillip Lougher 2011-04-15 15:05:09 UTC

in kernel-2.6.18-238.10.1.el5

linux-2.6-virt-hypervisor-overflow-fix-for-clocks-4ghz.patch

Comment 6 errata-xmlrpc 2011-05-31 14:08:52 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-2011-0833.html

Comment 7 Martin Prpič 2011-06-02 13:28:15 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:
Previously, on VMware, the time ran too fast on virtual machines with more than 4GHz TSC (Time Step Counter) processor frequency if they were using PIT/TSC based timekeeping. This was due to a calculation bug in the get_hypervisor_cycles_per_sec function. This update fixes the calculation, and timekeeping works correctly for such virtual machines