kern/84957: fire_saver.ko causes high CPU usage by swi5
Nick Johnson
freebsd at spatula.net
Mon Aug 15 16:00:31 GMT 2005
>Number: 84957
>Category: kern
>Synopsis: fire_saver.ko causes high CPU usage by swi5
>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: Mon Aug 15 16:00:28 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator: Nick Johnson
>Release: FreeBSD 5.4-STABLE i386
>Organization:
morons.org
>Environment:
System: FreeBSD turing.morons.org 5.4-STABLE FreeBSD 5.4-STABLE #2: Mon Aug 15 08:31:15 PDT 2005 root at turing.morons.org:/usr/src/sys/i386/compile/TURING i386
>Description:
I noticed, surprisingly high user CPU usage (circa 35%) when the machine was completely idle. top -S showed
that all of that 35% was going to swi5: clock sio. This was also driving the system load at idle up to 0.40
After mucking about with various kernel configuration options I noticed that after rebooting the usage of swi5
was reasonable for several minutes and then jumped up to 35%. It was then that I thought of checking to see if
I had configured a screen saver to load, and sure enough, I had fire_saver.ko loaded.
Unloading fire_saver.ko sent the usage of swi5 back down to 0%. I suspect somewhere in fire_saver.ko one might
find ugliness.
>How-To-Repeat:
Load fire_saver.ko. Wait for it to start. top -S
>Fix:
kldunload fire_saver.ko
>Release-Note:
>Audit-Trail:
>Unformatted:
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