kern/173541: load average 0.60 at 100% idle

[Viktor Štujber]

>Number:         173541
>Category:       kern
>Synopsis:       load average 0.60 at 100% idle
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Nov 10 23:50:00 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Viktor Štujber
>Release:        9.1-RC3
>Organization:
>Environment:
FreeBSD poring 9.1-RC3 FreeBSD 9.1-RC3 #0 r242461: Fri Nov  2 01:17:26 CET 2012     root at poring:/usr/src/sys/PORING  amd64

>Description:
I run FreeBSD on an intel atom D525MWV board. On recent FreeBSD versions, I am observing unusual load averages reported by 'top' even when 100% idle. It happens in a normal system, in single user mode, and on official usb install images. I have not yet confirmed if the load is real or if it's just kernel reporting the values wrong.

Here are kernels that I have tried. Four of them are from the currently available usb memstick installers; the 2011 one is a version I've been successfully using for a year until downgrading recently.

8.3-RELEASE  amd64 2012-04-09           -> load 0.02 after 5 minutes idle
9.0-RELEASE  amd64 2012-01-03           -> load 0.02 after 5 minutes idle
10.0-CURRENT amd64 2011-11-12 (cvs)     -> load 0.02 after 5 minutes idle
9.1-RC3      amd64 2012-10-30 (r242324) -> load 0.60 after 5 minutes idle
10.0-CURRENT amd64 2012-11-02 (r242464) -> load 0.60 after 5 minutes idle

>How-To-Repeat:
1) boot system on affected hardware(?)
2) leave 'top' running for a few minutes
3) observe load averages
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: