Description of problem:
During high database load testing (Oracle OLT) the kernel issues both of
these lost tick related warning messages:
1) kernel: warning: many lost ticks.
kernel: Your time source seems to be instable or some driver is
2) kernel: Losing some ticks... checking if CPU frequency changed.
Version-Release number of selected component (if applicable):
Under large Oracle OLT load testing, with 1000+ processes, this can
be reproduced 100% of the time.
Steps to Reproduce:
1. Create Oracle DB
2. Load OLT test kit (available at htto://oss.oracle.com/projects/olt)
3. Run large load with 1000+ processes
Machine will slow and kick out multiple lost ticks messages.
Only print lost ticks messages if booted with 'report_lost_ticks'.
Customer noticed this after they switched from SLES9 to RHEL5; in SLES9
there is only one place where lost ticks warnings are printed, and it
includes an if (report_lost_ticks) check before the code block.
Created attachment 266131 [details]
Created attachment 270051 [details]
RHEL5 fix for this issue
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
You can download this test kernel from http://people.redhat.com/dzickus/el5
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.