acpi_task_0 consuming cpu resource

[Robert Noland]

On Fri, 2009-08-07 at 18:27 +0800, C. C. Tang wrote:
> > Not sure then... I've got that board swapped out for a VIA board right
> > now.  It tends to be noisy enough in my office with all the other fans
> > running that I really can't hear that one.  I did have the smart fan
> > control enabled on both the case fan and cpu fan.  It also periodically
> > rebuilds lots of ports or kernels with -j 5, so if it was going to heat
> > up, that should do it...  If I can dig up a spare case and power, I'll
> > hook it back up and see if I can break it.  Otherwise it will have to
> > wait until I get done with the VIA driver...  I haven't really had any
> > issues that I can think of with that board, other than it is a bit slow
> > for compiling.  It runs amd64 just fine.
> 
> Really thanks for your reply.
> I will keeping watching it to see what situation in which the problem 
> will happen.
> I am running on i386 version and I think the compile speed is OK for me. 
>     Anyway it is not a very fast CPU :)
> 
> > Just remembering an issue that I had with some old p4 boxes though.  On
> > those boxes, when they got hot, they would trigger an acpi message that
> > was picked up by devd.  There was no way to throttle the messages, so it
> > would work the cpu as hard as it could, processing the messages.  The
> > only solution at that point was to power it off for a few minutes while
> > it cooled off and not work it too hard.  That sounds like what you are
> > seeing.  Are you seeing messages in syslog?
> 
> I have just done a
> # stress --cpu 1 --io 1 --vm 1 -d 1
> for several hours on the machine.
> Although it is not quite stressful, I think it is enough for it to reach 
> 100% load.
> But I didn't notice any such warning in the system log and the 
> acpi_task_0 problem didn't appear...
> 
> By the way I cannot read any temperature from acpi or smbus except 
> coretemp. (may be I loaded wrong driver?)
> So I am not sure how hot did the system got.

Yeah, IIRC coretemp is all I have gotten as well, but that is the
important one.

robert.

> Thanks,
> C.C.
> 
-- 
Robert Noland <rnoland at FreeBSD.org>
FreeBSD