Bug 690133

Summary: Time runs too fast in a VM on processors with > 4GHZ freq [rhel-5.4.z]
Product: Red Hat Enterprise Linux 5 Reporter: RHEL Program Management <pm-rhel>
Component: kernelAssignee: Zachary Amsden <zamsden>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: high Docs Contact:
Priority: urgent    
Version: 5.7CC: akataria, dhecht, dhoward, garrett, jpirko, jsavanyo, knoel, kzhang, mjenner, pbenas, plougher, plyons, pm-eus, prarit, qcai, sghosh, tburke, zamsden
Target Milestone: rcKeywords: ZStream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel-2.6.18-164.35.1.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: 2011-05-05 14:38:09 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: 673242    
Bug Blocks:    

Description RHEL Program Management 2011-03-23 12:13:52 UTC
This bug has been copied from bug #673242 and has been proposed
to be backported to 5.4 z-stream (EUS).

Comment 3 Phillip Lougher 2011-03-31 13:21:44 UTC
in kernel-2.6.18-164.35.1.el5

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

Comment 5 Zhang Kexin 2011-04-27 08:26:50 UTC
Hi Alok,
Would you like to test this bug for 5.4.z kernel please? If yes, we'll post the kernel to you. Thanks!

Comment 7 Eva Kopalova 2011-05-05 13:02:00 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.

Comment 8 errata-xmlrpc 2011-05-05 14:38:09 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/RHBA-2011-0489.html