frequent update_cpu_power messages in the system logs

This document (7015325) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 1 (SLES 11 SP1)
SUSE Linux Enterprise Server 11 Service Pack 2 (SLES 11 SP2)

Situation


Log messages relating to update_cpu_power appear frequently in the system logs:

Jun  6 13:17:12 myhost kernel: [87824625.772466] update_cpu_power: cpu_power = 28614818560; scale_rt = 49748003745
Jun  6 13:17:12 myhost kernel: [51795828.865150] update_cpu_power: cpu_power = 24528796992; scale_rt = 42644292225
Jun  6 13:17:12 myhost kernel: [87824626.024221] update_cpu_power: cpu_power = 21251351804; scale_rt = 36946323002
Jun  6 13:17:12 myhost kernel: [87824626.036207] update_cpu_power: cpu_power = 20892174701; scale_rt = 36321879278
Jun  6 13:17:14 myhost kernel: [87824627.762462] update_cpu_power: cpu_power = 28542184816; scale_rt = 49621727084

These messages may have non-consecutive timestamps.

In the example above, it can be seen that the timestamps from the kernel are not
all consecutive.

Jun  6 13:17:12 myhost kernel: [87824625.772466]
Jun  6 13:17:12 myhost kernel: [51795828.865150]
Jun  6 13:17:12 myhost kernel: [87824626.024221]





Resolution

Update to SLES 11 SP3 or later, which is not effected by this issue.

SLES 11 SP2 is not effected by the issue, however a patch has been provided as a
precautionary measure in kernel-3.0.101-0.7.19.1, which is available to customers with
Long Term Service Pack Support (LTSS).

Customers who have LTSS for SLES 11 SP1 can update to kernel-2.6.32.59-0.13.1 or later.

Cold booting the system at a minimum of every 208 days should avoid the issue.

Cause


Additional Information

Additional checks were put in place to protect scale_rt_power() from clock
aberrations, and also to prevent any anomalous value returned by scale_rt_power()
from being stored in load balancing structures to be encountered at some later time.

As a safety measure was implemented to avoid potential overflows in the clocksource.

Also, changes were made to limit the number of update_cpu_power messages that would
be logged.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7015325
  • Creation Date: 03-Jul-2014
  • Modified Date:12-Oct-2022
    • SUSE Linux Enterprise Server

< Back to Support Search

For questions or concerns with the SUSE Knowledgebase please contact: tidfeedback[at]suse.com

SUSE Support Forums

Get your questions answered by experienced Sys Ops or interact with other SUSE community experts.

Join Our Community

Support Resources

Learn how to get the most from the technical support you receive with your SUSE Subscription, Premium Support, Academic Program, or Partner Program.


SUSE Customer Support Quick Reference Guide SUSE Technical Support Handbook Update Advisories
Support FAQ

Open an Incident

Open an incident with SUSE Technical Support, manage your subscriptions, download patches, or manage user access.

Go to Customer Center