Bug 107683
| Summary: | cpu idle counter in /proc/stat can be unstable | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Chris Bertin <chris.bertin> |
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> |
| Status: | CLOSED ERRATA | QA Contact: | Brian Brock <bbrock> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 8.0 | CC: | riel |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i686 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2003-10-22 07:47:53 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: | |||
your kernel is very very old and has been obsoleted by like a dozen errata releases.... |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; HP-UX 9000/800; en-US; rv:1.2.1) Gecko/20030409 Description of problem: All CPU counters in /proc/stat should be ever increasing (until they wrap, at least) but, on some systems with the kernel version above, the idle counter can go up and down by one: # while : ; do grep cpu0 /proc/stat; sleep 5; done cpu0 899789 34080527 878200 275371855 cpu0 899794 34081013 878210 275371855 cpu0 899801 34081500 878217 275371855 cpu0 899807 34081986 878226 275371854 cpu0 899815 34082473 878232 275371855 cpu0 899823 34082959 878238 275371855 cpu0 899830 34083445 878247 275371855 This happens when the CPU is 100% busy. To force this condition, a simple loop will do: # while : ; do : ; done This can also happen on MP systems. It confuses performance tools. Version-Release number of selected component (if applicable): kernel-2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 How reproducible: Sometimes Steps to Reproduce: 1. while : ; do : ; done & 2. while : ; do grep cpu0 /proc/stat; sleep 5; done 3. Actual Results: Idle counter goes up and down by one. Expected Results: Idle counter or any other counter should never go down. Additional info: