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 hogging interupts 2) kernel: Losing some ticks... checking if CPU frequency changed. Version-Release number of selected component (if applicable): 2.6.18.* How reproducible: 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 Actual results: Machine will slow and kick out multiple lost ticks messages. Expected results: Only print lost ticks messages if booted with 'report_lost_ticks'. Additional info: 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] enforce report_lost_ticks
Created attachment 270051 [details] RHEL5 fix for this issue Updated patch.
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 release.
in 2.6.18-61.el5 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. http://rhn.redhat.com/errata/RHBA-2008-0314.html